Saturday, March 31, 2012

Statistik Umum Perolehan QSO YB8Y


http://topbanddxdiindonesia.blogspot.com/2012/03/statistik-umum-perolehan-qso-yb8y.html

Statistik Umum Perolehan QSO YB8Y


Ini bukan artikel untuk bertepuk dada!

Sehubungan dengan terlampauinya sasaran 10.000 buah QSO oleh YB8Y (merupakan rekor baru dan skor tertinggi dalam sejarah kegiatan DXpedition + kontes CQWW WPX oleh tim Orari hingga pesan ini ditulis), di bawah ini saya sertakan statistik umum berisi data QSO YB8Y dari dari Club Log dalam bands, modes dan prosentasenya.

Titik berat saya berikan kepada LOW bands yang menjadi assignmentutama untuk saya dan kawan-kawan.

Pemuatannya tidak dimaksudkan untuk mengecilkan arti dan fungsi-fungsi segenap anggota tim yang bertugas pada band-band lain sesuai jadwal kerjanya melainkan hanya untuk menggambarkan perolehan secara obyektif dan rinci (lihat gambar bawah).


Sumber: http://yb8y.com/online-logs/

Prosentase perolehan mode CW yang rendah (di bawah 50% dari total QSO per band) hanya terjadi pada bands 20m dan 15m. Seingat saya memang telah terjadi kondisi propagasi buruk yang lama pada keduaband tersebut.


Gbr.1. OM Tatang YB1MH Spesialis band 6m.

Yang menyenangkan adalah melihat perolehan QSO lebih dari 50% padaband 6m yang dikawal oleh OM Tatang YB1MH (Gbr. 1.).

Saya sendiri luput menyaksikannya beraksi karena saat komunikasi dua-arah terjadi pada magic band tersebut, saya sedang tugas (atau sedang tidur, ya? Lupa saya).


Gbr.2. Ria, YB0KVM di samping Ito yang sedang merokok Jisamsu

Jumlah QSO dalam modeRTTY juga cukup mengesankan, menurut saya. Salah satu operator tangguhya adalah Ito-sanJA1PBY/WK1S. Satu-satunya warga negara asing dalam tim kami.



Gbr.3. Balun DX Engineering, 10KW pada feedpoint antena tx 160m

Adalah bukti bahwamother nature amat tajirdan senang memberi.
Di batang pohon kelapa setinggi 20m inilah kami menempatkan kerekan(pulley) untuk feedpoint + balun 1:1 bagi antena TXfull-sized dipole.

http://topbanddxdiindonesia.blogspot.com/2012/03/statistik-umum-perolehan-qso-yb8y.html

Foto-foto YB8Y OC-221 di Pulau Ohoiew, Kei Kecil, Maluku Tenggara


http://topbanddxdiindonesia.blogspot.com/2012/03/foto-foto-yb8y-oc-221-di-pulau-ohoiew.html

Foto-foto YB8Y OC-221 di Pulau Ohoiew, Kei Kecil, Maluku Tenggara



Saya berharap, foto-foto dan sekelumit teks penjelasannya dapat memberi gambaran tentang kondisi YB8Y, Maret 2011.
Gbr.1. (kiri) Awak ATR-72 sarapan dan safety first di Ambon.



Gbr.2. Siang hari, saya tiba di Langgur, lapangan terbang di Tual yang juga merupakan landasan pesawat terbang TNI-AU di Maluku Tenggara.



Gbr.3. Jalan darat dari Langgur ke desa Ngilngof yang terletak di ujung pulau untuk menyeberang ke pulau Ohoiewyang tak berpenghuni.



Gbr. 4. Kediaman OM John, YB8YZ di desa Ngilngof, Tual.
Dermaga - kalau pun bisa disebut demikian- ada tak jauh dari pintu halaman rumahnya



Gbr. 5. Barang-barang untuk YB8Y yang dikirim dengan kapal PT Pelni dari Jakarta sepuluh hari sebelumnya sudah tiba di Ngilngof.
Berat keseluruhan lebih dari 1 ton. Semuanya diasuransi all-risk pergi-pulang.



Gbr. 6. Sebagian anggota tim teknis yang tiba dua hari lebih dulu dari pada kedatangan saya sedang bekerja di hutan Ohoiew.



Gbr 7. Gambar di kiri merekam kegiatan mendirikan antena tx untukband 160m dengan bambu. Perhatikan rangka atas untuk Gubuk #1 yang belum diberi atap rumbia, di sisi kanan gambar



Gbr.8. Ini yang namanya rayuan pulau kelapa dan nyiur melambai,kaleee.
Di pagi yang cerah, awan berarak dan langit lazuardi membuat pesona di Ohoiew yang tiada tara.



 Gbr. 9. Rizal, YD1ORZ sedang merakit antena Yagi, homebrew, untuk 28 MHz. Di latar belakang tampak gubuk operasi di pinggir hutan bersemak lebat



Gbr. 10. Saya di samping OM Sur YB0JS menyeberang dari Ngilngof ke pulau Ohoiew..
Untuk keamanan, kami mengenakan pelampung



Gbr. 11. Bintang laut di laut Ohoiew dapat dilihat dengan mata telanjang. Airnya jernih dan Anda tidak perlu nyilem



Gbr.12. Gubuk #1 yang sudah jadi. Di sini, seluruh operasi pada high bands (all modes)dilaksanakan.
Menurut saya, gubuk ini jauh lebih nyaman dari pada yang pernah dimiliki Robinson Crusoe saat dia terdampar dalam dongeng kesohor. Cintaku jauh di pulau. tapi, alm. Benyamin S memplesetkannya menjadicintaku berat di ongkos... Pilih mana?



 Gbr. 13. Sur YB0JS (berdiri), Gjellani YB1GJS dan Wisnu YB0AZ sedang 'siaran langsung'



Gbr. 14. Dalam dua hari terakhir di pulau, ruang siaran untuk hi-bands dipindah ke lantai dasar bungalow. Saat itu, YB8Y berpartisipasi dalam kontes WPX SSB, 2012. Tampak OM Eko, YB0VKI (berdiri) mengawasi para "siswa".



Gbr. 15. Gubuk #2 di mana operasi pada LOW bands dilakukan.
Letak Gubuk #1 dan Gubuk #2 hanya berjarak sekitar 10 s/d 15 meter dari bibir pantai



Gbr. 16. Terry YC1KAF (bertopi) dan Joz YD1JZ, sedang bertugas mengoperasikan stasiun-stasiun 80m dan 40m CW



Gbr. 17. Pakai kacamata hitam untuk menutupi mata merah karena mengantuk.


Gbr. 18. Di Ohoiew, Anda bisa tidur amat lena walaubarefoot abiisss...



Gbr. 19. Saya tidur pulas di siang hari dengan bantal dan mimpi'the American dreams'. Sebuah kemewahan yang istimewa



T A M A T
Jangan lupa memeriksa barang-barang Anda supaya tidak ketinggalan :-)
Foto-foto dibuat oleh semua anggota tim YB8Y

http://topbanddxdiindonesia.blogspot.com/2012/03/foto-foto-yb8y-oc-221-di-pulau-ohoiew.html

SPRING LITES QSO PARTY (SL)

http://arlhs.com/SL-2012-guidelines.html


 The ARLHS Presents Its Annual 

SPRING LITES QSO PARTY (SL)





  • P urposes:



  • To promote public awareness of ham radio and lighthouses; to contribute to the recognition that lighthouses, lightships, and their keepers deserve; to foster camaraderie within the ham fraternity; and to provide fellowship amongst the members of the Amateur Radio Lighthouse Society



  • Dates & Times:



  • 0001 hrs UTC on March 31, 2012, through 2359 hrs UTC on April 08, 2012.



  • Suggested Modes / Calling Frequencies:



  • Any and all modes : SSB, CW, RTTY, PSK, FM, SSTV, etc.



  • Suggested SSB freqs: 1950-1990, 3950-3990, 7250-7290, 14.250-14.290, 21.350-21.390, 28.350-28.390
    (Calling on the centered 0.70 kHz on each band — Example: 14.270.)



  • Suggested CW center freqs: 1830, 3530, 7030, 14.030, 21.030, 28.030
    Note that these are center calling frequencies. Work 20 kHz each side of center.



  • NO CREDIT will be given for contacts made on WARC bands.



  • To alleviate QRM, spread out and work SSB from 50 kHz to 90 kHz and on CW work from 10 kHz to 50 kHz (i.e., +/- 20 kHz of center.)



  • Scoring:



  • IMPORTANT: Answers to some common scoring questions can be found on the Scoring FAQ page at http://arlhs.com/scoring.html



  • Each contact (member or nonmember) = 1 pt.



  • Add 2 points more if contact is an ARLHS member



  • Add 3 points more if contact is at a lighthouse or lightship



  • NO CREDIT and no points will be given for contacts made on WARC bands.



  • BONUS for activating a light: As an incentive for participants to activate a light beacon, we are instituting a multiplier. If you activate a lighthouse or lightship under the rules of the ARLHS, you qualify for an additional 2x multiplier of your total score (as determined above). If for example your base score is 600 points and these were all accumulated by your operation at one of the recognized ARLHS lights (see the ARLHS World List), multiply your 600 points x 2 = 1200 points final score. This will be indicated on the final scoring cover sheet, which MUST be attached for log to qualify — see section below under "Log Submissions."



  • sample log sheet in Microsoft Excel (XLS) format can be found HERE, but you can use whatever format is most comfortable for you. You do NOT have to use this log sheet, provided that all the usual, pertinent information is obvious. Whatever log format you use, you MUST always attach as a top sheet a Scoring Summary Cover Sheet (see http://arlhs.com/score-coversheet.html for a sample) as the cover sheet foreach log. See "Log Submissions" below for more logging details.



  • Example:



  • You work ARLHS member #155 who is at lighthouse ARLHS USA-701.



  • Your score for this contact is 1 pt for the contact, plus 2 points



  • for working a member, plus 3 points for working a lighthouse.



  • Total score for this QSO = 6 points.



  • Answers to some other common scoring questions can be found on the Scoring FAQ page at http://arlhs.com/scoring.html 



  • Exchanges:



  • ARLHS members send call sign, member number, name, state/province/country



  • Non-members send call, sequential contact number, name, state/province/country



  • Lighthouse/Lightship Stations send call, ARLHS lighthouse number, name, state/province/country



  • NOTE: A numbered list of ARLHS lighthouses is available from page 10 of the Society's web page at http://arlhs.com




    • CERTIFICATES & PRIZES
      For NON-MEMBER Participants: Non-ARLHS members are eligible for the following certificates and prizes:
      • First Prize: The non-member entrant achieving the highest total number of points will receive a one-year full Active membership in the ARLHS.
      • Second Prize: The non-member entrant receiving the second highest total number of points will receive a one-year Inactive membership in the ARLHS.
      • Third Prize: The non-member entrant receiving the third highest total number of points will receive a certificate of recognition.
      • A certificate is available with endorsements for those who work at least 50 lighthouses or at least 100 members of the ARLHS. Another certificate is available for those who work the club station, W7QF, during this event. The shipping fee for each certificate is $2.00 + an enclosed SASE with sufficient postage (see Log Submissions below). SASE is required for all certificates.
      • The ARLHS offers several Awards for contacting light beacons (WAS-LH, WACA-LH, DX-LH, etc.). See the Society's Award Program on web page 9 for details and application forms.
      MEMBERS ONLY Prizes and Awards: The following prizes and awards are available ONLY TO ACTIVE MEMBERS of the Amateur Radio Lighthouse Society (ARLHS). "Active" means that dues are current and paid thru the beginning date of the event. Be sure that your membership has been renewed!
      • First Prize: The member entrant receiving the highest total number of log points will receive a choice of any two prizes from the ARLHS store..
      • Second Prize: The member entrant receiving the second highest total number of points will receive his/her choice of a prize from the ARLHS store..
      • Third Prize: The member entrant receiving the third highest total number of points will receive a coffee mug from the ARLHS store..
      • A certificate is available with endorsements for those who work at least 50 lighthouses or at least 100 members of the ARLHS. Another certificate is available for those who work the club station, W7QF, during this event. The mailing fee for each certificate is $2.00 + a SASE with sufficient postage (see Log Submissions below). SASE is required for all certificates.
      • MINIATURE COLLECTIBLE LIGHTS: We are once again able to offer a miniature collectible lighthouse to all ARLHS member participants. Each ARLHS member entrant who submits a valid log showing contact with at least ten other active ARLHS members or five lighthouses during this event is eligible to receive a miniature lighthouse collectible. (See sample HERE. This is a sample only. Yours will be of a different light. Selection is random, based on available stock.)
        (Sorry, there is no choice of lighthouse at this time — selection is random.)
        Due to increases in postage costs, we must ask the applicant to pay shipping and handling charges of US $5.00. Payment should be in USA funds by USA check, cash, or money order (no IRC's). All checks should be made payable to "Weidner Publishing." Sorry, there is a limit of only ONE light per entrant.
      • In addition, the usual series of ARLHS awards is also available, and these are described on the Society's Award Program page 9.


      LOG SUBMISSIONS


      [1] Put your call & member number on EVERY PAGE of your log and on ALL other material submitted, including envelopes and checks.

      [2] sample log sheet in Microsoft Excel (XLS) format can be found HERE, but you can use whatever format is most comfortable for you. You do NOT have to use this log sheet, provided that all the usual, pertinent information is obvious. Whatever log format you use, you MUST always attach as a top sheet a Scoring Summary Cover Sheet (see http://arlhs.com/score-coversheet.html for a sample) as the cover sheet foreach log. If you choose to use your own version of a cover sheet, then it must at least include all items and elements on the ARLHS version: It should show the total points for all contacts; total points for member contacts; total pts for lighthouse contacts; grand total of points for that log a detailed list of all certificates, endorsements, and prizes applied for; and a listing of all amounts and totals of checks or money submitted.
      Versions of the cover sheet from previous ARLHS contests and events are not valid.
      Logs without the Summary Cover Sheet showing all required proper information will NOT be counted and no refunds will be made. 

      [3] All logs MUST specify the entrant's call on EACH page of the log and clearly indicate the entrant's name, address, and member number (if applicable) on the first page, as well as on the summary score sheet. 

      [4] All checks should be in US funds made payable to "Weidner Publishing." NOTE: IRC's are no longer accepted. 

      [5] NEW! Each operation from a different QTH (home, mobile, lighthouse) using the same call but with a /P, /MM, or /M designation requires a separate log and separate score sheet. The scores from each log will then added together on the Summary Score Sheet to determine the final event score. 

      [6] Send log data to the Contest Manager:
      Dave Ruch, NFØJ 
      P.O. Box 20696
      Bloomington, MN 55420-0696 

      [7] Include a self-addressed 9 x 12-inch envelope with return postage (97 cents for USA -- IRCs are NOT accepted anymore), along with $2.00 (US) for each certificate requested. Entries received without an SASE will not be acknowledged or returned. 

      [8] Deadline for submissions is APRIL 30, 2012. All logs must be postmarked by this date. Late entries can not be accepted. No exceptions!

      [9] NO refunds will be made for logs and/or applications submitted improperly or without Summary Score Sheet and in proper form. Once submitted there are *NO* refunds! 
      [10] Although a sample log sheet is shown on the web site, any format of log sheet can be used, according to your preference, but be sure your log shows all appropriate information; e.g., Date, time (UTC preferred), station worked, op's name, member or sequential number, state or province, band, mode — whatever the event calls for.

      [11] Rules, guidelines, criteria, prizes, etc, as cited herein, are subject to change at any time without notice and are at the sole discretion of the Amateur Radio Lighthouse Society.
      • NOTE: Failure to observe all rules for log submissions (see above) will result in disqualification. In such cases there will be NO refunds of any fees. Decision of the judges is final.
      • These guidelines apply to this event only. They do not apply to other ARLHS-sponsored events, which have their own set of guidelines. See the ARLHS Awards Program page for fees and details on applying for ARLHS awards. 
      • Further Information :
      • E-mail to Jim: weidner [at] waterw.com
      • SASE to ARLHS- Weidner Publishing, 114 Woodbine Ave, Merchantville, NJ 08109
      • SASE to Contest Manager, Dave Ruch, NFØJ, P.O. Box 20696, Bloomington, MN 55420-0696
      • Telephone to NJ: (856) 486-1755

      Friday, March 30, 2012

      CW ACADEMY





      INTRODUCING: CW ACADEMY
      Take a CWops CW Quick Quiz
      Learn how you can benefit from the CWops CW Academy

      For the beginner
      1. Want to communicate with fellow hams around the world using even a modest rig and antenna?
      2. Want to stay in touch when on vacation to some remote area where you don't have access to a repeater or cell phone service?
      3. Want to meet a whole new community of amateurs that share a common bond?
      4. Want to expand your operating capabilities with little or no cost?

      If you answer "Yes" to any of the questions, then becoming skilled in CW is the answer.

      CWops CW Academy advisors are ready and willing to teach you a new skill that will open a world of fun and opportunity
      For those having experience with CW who want to improve or regain proficiency

      1. I am getting bored with voice and digital modes
      2. My CW skills are not what they used to be
      3. I'm too rusty or embarrassed to get back on CW
      4. I want to be able to copy in my head

      If you know the code but are rusty, can't copy or send as proficiently as you once could, then CWops CW Academy is right for you
      For those that want something new but are not confident to take the plunge

      1. I love chasing DX and I want to try something new
      2. I like contesting and would like to be better at CW radiosport
      3. I've tried CW learning aids but nothing seems to work for me
      4. CW intrigues me but I'm worried about the challenge

      If this sounds like you, then CWops CW Academy is absolutely right for you and is available to anyone, anywhere --- membership in CWops is not required.

      Sign up now to talk with one of our CWops CW Advisors and learn what CW Academy can do for you.

      STUDENTS AND
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       http://www.cwops.org/cwacademy.html

      Thursday, March 29, 2012

      Ham Station Desk Radio Equipment Ground



      Ham Station Desk Radio Equipment Ground


      RF in the Ham Shack

      It is commonly assumed "RF in the shack", interference to consumer devices like telephones or stereos, or even RF feedback or RF burns are tied to operating position grounding problems. There is also a belief that our equipment needs to be grounded to a good RF ground, and the lack of an RF ground will cause poor reception, a weaker transmitted signal, and a host of other maladies. Another popular belief is that each piece of desktop equipment needs to have separate leads to a ground point so RF doesn't move from the chassis of one piece of gear to another. Sometimes we read that beads or isolators are recommended on coaxial cables running between pieces of equipment.
      The beliefs above are actually not true except in very specific (and uncommon) installations! I also strongly believed in RF grounds on my desk. Eventually I learned they, very often, didn't do anything but hide the real problems.

      What Causes RF Problems in Equipment?
       In a perfectly engineered world RF would not bother anything except devices intentionally tuned to the frequency of the RF. Blame for RFI ultimately lies with the device that is not supposed to be affected or controlled by RF being affected by RF. Other than correcting the operation of the device wrongly being affected, there are two reasons to have troublesome RF levels in the house or at the operating position:
          1.) The antenna system has a design, engineering, or installation flaw.
          2.) The antenna is too close to the house or operating position.
          3.) The problem is not RF at all, but is a DC power supply ground loop back into the audio system

      Why or when is a ham station ground necessary?
      Sometimes we set ourselves up for problems without knowing it.
      • Antennas with high levels of a phenomena called "common-mode current" can bring a great deal of RF back into the shack via the feedline
      • Certain types of equipment with improper enclosure design or improper interconnection design creates problems. Examples are poor ground terminal path planning
      • Some equipment is not designed properly on input or output ports, and the poor port electrical design creates or aggravates problems. Example are excessively low voltage threshold on control lines
      • At times our antennas are too close to the operating position, causing every wire in the house to become a receiving antenna and a potential source of unwanted strong RF
      Note: We should not assume distorted or bad audio is always RF feedback or RF related problems. Sometimes it can be direct current ground loops in station audio that allow power supply current load variations to modulate the transmitter. Audio lines that route from one piece of gear to another should always be grounded through a chassis ground path only at one end of the cable. For example a microphone input has a ground inside the radio. If an external device is connected to the mic jack, and that external device grounds the mic shield back to the station ground or power mains safety ground, it will introduce hum into the audio. If the 12V power supply is similarly grounded (as it should be) to the mains safety ground, audio-rate modulation of the 12V supply can be coupled back into the mic input shield and modulate the transmitter. This distortion sounds very much like "RF feedback", but it is an audio shield ground loop issue. In the professional audio world this is called a "pin 1 problem".This is more than an audio line problem. Manufacturers can also put a "pin 1 problem" into power supply and control lead connections. THE ONLY PLACE FOR A SHIELD GROUND OR 12 volt POWER SUPPLY NEGATIVE LEAD GROUND IS DIRECTLY TO THE CHASSIS.


      What causes equipment cabinets to be hot with RF, a change in noise, a change in RFI, or a change in SWR when a ground is connected or removed from equipment?
      If connecting or disconnecting a operating position ground causes a change in noise level, SWR, reception, transmission, RFI, or TVI.....your equipment has significant RF flowing over the wiring or cabinets. This type of unwanted current is called common-mode current . Common-mode current is not flowing inside a cable shield or as the proper balanced-current in a parallel wire feedline. Common-mode current is like currents that cause antenna radiation, and it flows on the outside of shields and as an imbalance in phase and/or level in parallel line conductor currents.  Common-mode current explanation. 
      This is worth repeating...we should not assume distorted or bad audio, or other anomalies during transmission, are always an RF feedback or RF related problem. The problem might be direct current ground loops in station audio wiring, or in control wiring, allowing power supply current load variations to modulate the transmitter audio or control lines. Audio lines that route from one piece of gear to another should always be grounded through a chassis ground path only at one end of the cable. For example a microphone input has a ground inside the radio. If an external device is connected to the mic jack, and that external device grounds the mic shield back to the station ground or power mains safety ground, it will introduce hum into the audio. If the 12V power supply is similarly grounded (as it should be) to the mains safety ground, audio-rate modulation of the 12V supply can be coupled back into the mic input shield and modulate the transmitter. This distortion sounds very much like "RF feedback", but it is an audio shield ground loop issue.
      A second problem is poor design of some devices, in particular external audio interface devices. Not only should external systems isolate shield paths with suitable audio isolation transformers, if they contain semiconductors they should employ properly designed RF bypassing. Many devices do their intended audio frequency job very well, but are inadequately designed for use in high RF fields.

      What causes common-mode current?
      Current flows when there is an electrical potential (voltage) difference between two parts of a system, and a conductor between those point to carry current. There are also special currents, without actual electron movement, called displacement currents. Displacement currents flow through capacitor dielectrics, between a vertical or single wire fed antenna and the "ground" for that antenna, or even between a mobile antenna and a car body. Any two things that have capacitance between them can have displacement currents flowing through that capacitance.
      Displacement currents commonly complete the current path in open-ended antennas, although all antennas have displacement currents. Displacement currents are the reason an open-ended antenna like a dipole, longwire, or vertical is able to have current flowing out to the antenna end, even though the insulated end just hangs in the air!  They are also one of the reasons current tapers in an antenna, instead of being equal through the entire length of the antenna. This displacement current has to somehow get back to the feedpoint, and is a major cause of common-mode currents. There are several other causes, but they involve more easily understood circuit paths.
      The amount of current is dependent on path common mode impedance and the source and termination characteristics. This is why some people claim ferrite beads work wonders, and why other people claim the same very beads won't work. Band-aide patches, like peppering a flawed installation with beads to correct a problem caused somewhere else in the system, are very system dependent.

      The Feedline

      If you are not familiar with how coaxial cables work, you might want to look at a simple  explanation on this site or one of the ARRL Handbooks.
      In order for a conductor (like the outside of the shield) to not have current flow at radio frequencies, it must have the same electrical potential and phase all along the length. If it has a high series impedance (common mode impedance) or if the potential difference along the conductor is low, very little current will flow. As seen in coaxial cable operational descriptions, any coaxial feedline can have unwanted common mode currents.
      Does a vertical or longwire present high common mode voltages to the feeder that can cause common mode currents? You bet it does! The only vertical (or longwire) that would not cause such problems is one with a very good or nearly perfect ground system, and that means something that electrically looks or behaves like an infinite groundplane. Even then, the cable must exit below that groundplane to be "shield current free".
      Most excessive operating position RF level problems are caused by the antenna system
      Bringing a longwire or some other single wire feed system directly into the operating position will create high levels of RF in the station. This is because, unlike two-wire balanced lines or coaxial cables, a single wire feeder has no other terminal or return conductor to "push against" for currents flowing to and from the antenna. Longwires, random wires, inverted L's, true Windom antennas, or any other single wire "feeder" or antenna require a desk RF ground connection. When such antennas or feedlines are brought into the shack, they also bring grounding problems to the operating area. Another troublesome antenna is the OCF (off center fed) dipole. It is an antenna with severe common mode problems, even though it has a two-conductor feeder.
      Some verticals are problems for common-mode currents also, because they lack a proper ground. A vertical is most often an end-fed antenna. Sometimes the element is 1/4 wave, at other times 1/2 wave or 5/8th waves long. If we do not use a perfect "zero impedance" ground system, vertical antennas can excite their feedlines with significant common mode current.
      An RF ground for house equipment is never required when using properly functioning two-conductor lines such as coaxial cable or open wire transmission lines. With properly operating coaxial or balanced feedlines,  the operating position should have minimal RF levels even when a shack or desk ground is totally absent! My present stations do not have RF grounds at the desks or inside the room, as was also true for every one of my stations since the later 1970's.  I have used desk-top safety grounds with older gear, specifically older 120V-operated vacuum tube transmitters and receivers (you'll understand why later), but that is always for safety and not for RF grounding.
      If you have two-conductor feeders, either in the form of standard coaxial feedlines or balanced transmission lines, and have RF in the shack or see a change in noise level, transmission, reception, TVI, or other problems when a station ground is connected or disconnected, you really have a different problem. If you have RF problems and have good cabling between various pieces of gear, it is probably not a ground connection problem. Your antenna system feedline or other conductors entering the shack  probably have significant common mode currents.   The sole exception to this is when single wire feeders are brought into the desk area.

      Log Periodics and RFI
      One problem I have helped two or three people with is their improper routing of coaxial cables on their e log periodic antennas.   In all cases they were trying to cure severe RFI and "hot cabinets" in the radio room with chokes and beads and grounding. The real problem was at the antenna. With the antenna feed corrected, their problems went away without suppression beads in the shack or RF grounds in the Ham shack.
      Dipoles
      In the case of a dipole antenna, each feedpoint terminal has "voltage to earth". If a perfectly balanced dipole has 100 volts across the feed terminals, the feedpoint would have about 50 volts to an imaginary groundplane bisecting the antenna center.





      The current pattern to the left is for a 1/2 wave dipole 1/2 wl above ground, with coaxial feed. You can see the feedline shield has significant current. In this case about 40% of the antenna's maximum current!





      We can simulate a choke balun by adding a current source in series with the shield and setting current for zero amperes. The voltage across that current source will indicate the common mode voltage exciting the feedline.




      Adding a perfect choke balun, current on the feedline shield goes to zero and the voltage across the choke balun is now found from the source menu:
      Source 1 Voltage = 61.02 V. at -0.01 deg.
      Current = 1 A. at 0.0 deg.
      Impedance = 61.02 - J 0.009274 ohms
      Power = 61.02 watts

      Source 2 Voltage = 37.42 V. at 173.27 deg.
      Current = 0 A. at 0.0 deg.
      Impedance is infinite
      Power = 0 watts
      Source 1 (61 volts) is the actual terminal excitation of the dipole, while source 2 (37.42  volts) is the voltage that would cancel common-mode feedline current. We can see the voltage across the perfect balun is indicated by source 2 as 37 volts. This is slightly more than 1/2 the feedpoint differential voltage. (We could also use a very high impedance load in the feedline of the model and show the same thing.)


      This is a substantial amount of shield excitation. It is easy to see how a dipole without a good balun might cause RF problems at the operating desk. We fix this by "grounding the heck out of the station", but the real cause and best cure would be fixing our antenna. by the way, a few turns of coax on an air-core form is not a good balun at all. It takes almost 15 turns 4" in diameter to make a good 40 meter balun, and the impedance is mostly reactance. The choke location has to be carefully planned when using an air-core balun. Depending on cable lengths and balun or choke location, adding an air core balun or choke can even make things worse! If we use an iron core with a high loss tangent, most of the impedance will be a resistance. This will increase common mode isolation over a much wider bandwidth. A high resistance low-Q balun is much better for bandwidth and much less critical for location in the system.
      Dipoles, even though balanced antennas, can have problematic common mode currents when fed improperly. Without a balun some feedline lengths can cause problems, while other feedline lengths can actually eliminate need for a balun. One popular balun and unun handbook claims a dipole does not need a balun because the feedline is a very small diameter in wavelengths. That isn't true at all. The author tested the need for a balun while using a 1/4 wavelength vertically handing feedline, a case where his choice of feedline length just happened to eliminate the need for a balun. It was nothing to do with the feedline diameter being small!
      There is no universal magic feedline length that minimizes common mode currents in every installation. The length required to minimize common mode varies with feedline routing, grounding, and surroundings. If we have a very specific situation, like a vertical feedline hanging vertically in open air from a dipole center, and that feedline runs straight down to earth and is grounded at earth's surface, we can predict the feedline length to minimize common mode without a balun. The magical length in this specific case is 1/4λ or any odd quarter wavelength of cable length between the antenna feedpoint and ground. Since the primary dielectric between the cable shield and earth or the antenna is air, feedline velocity factor is meaningless! If we inserted a common mode choke right before the ground on the antenna side of the ground, it would maximize common mode problems! We have to be careful throwing parts at a system hoping something will stick.

      Verticals  with less than infinite groundplanes

      Here is a model of a groundplane with four radials:

      EZNEC ver. 3.0
      Balun 80 vertical 1/3/04 7:19:05 PM
      --------------- CURRENT DATA ---------------
      Frequency = 3.6 MHz.
      Wire No. 1:     6.700 (antenna element)
      Wire No. 2:     1.359 (This is your feedline or mast)
      Wire No. 3:     1.985 (radial)
      Wire No. 4:     1.985 (radial)
      Wire No. 5:     1.985 (radial)
      Wire No. 6:     1.985 (radial)
      We can see significant current flows over wire 2, which would be the coax shield, a mast, or both.


      There is a trick we can use with Eznec. By inserting an additional source in the mast or feedline and setting current to zero, we can observe the radial common point to earth voltage required across a balun to force current to zero. In this case the voltage across the balun would be:
      Source 2 Voltage = 145.5 V. at 67.97 deg.
      Current = 0 A. at 0.0 deg.
      Impedance is infinite
      Amazing isn't it? At 1500 watts the ground common point for the radial system actually wants to have 145.5 volts to earth to prevent current flow along the outside of the shield!! If we elevate the common point to 145.5 volts at 68 degrees phase angle, we now have the following currents at 1500 watts:
      Wire No. 1: 6.4 A (antenna element)
      Wire No. 2: 0 A (coax shield or mast)
      Radials: 1.58 A each (antenna radials)
      How many times have we been told four resonant carefully tuned radials make a perfect ground? Obviously any claim four radials form a perfect ground is not true. If it was a perfect ground center point of the radials would be at zero volts. With four radials the antenna is not perfectly unbalanced. Since the antenna is not perfectly unbalanced, some feedline lengths or grounding arrangements will allow appreciable current to flow over the coax shield.
      Is it any wonder we have RF problems with some of our antennas?
      End-fed Antennas
      End-fed antennas, be they so-called "end-fed dipoles", zepps, or longwires all offer a very good chance of having RFI problems. They might require multiple stages of feedline decoupling to reduce in-the-shack RF problems.  You can see some examples of problems they create by looking at my page about  end fed zepps and other end fed antennas.

      Other Systems

      Windom antennas produce considerable common-mode because the antenna is neither unbalanced nor balanced. They require special common-mode isolation techniques, such as a very good current balun  or a combination of current baluns and other choking devices.
      Full-wave loops operated on their fundamental frequency generally don't create excessive common-mode problems, but they can when operated on harmonics.

      Eliminating Common Mode Problems


      We commonly hear that a few turns of coax on an air core form makes a good balun or device to cure common mode currents and RFI problems. This just isn't true in most cases.
      Even if we use enough turns to provide a high reactance, which many suggested baluns of 5 to 10 turns do not, the resulting reactance is generally inductive on lower bands. Depending on the common mode impedance of the system the balun or choke is inserted in, the reactance can do anything from reduce current to greatly increase current. I use ten-to-twenty turn, 4" diameter, air core choke baluns on some of my yagi antennas. I locate them right at the balanced feedpoints, I tape the coax leaving the choke balun to the boom,  and I use a barrel connector as a connection point to the feed cables running down the towers. I ground the barrel connector to the antenna boom.
      This establishes a very good reference point for common mode impedance. I know the common mode impedance at the connector is reasonably low (because it is grounded to the boom and tower), and I know any series reactance, especially inductance, will greatly decrease common mode currents.
      F12 antenna baluns

      Typical of my Force-12 Yagi baluns




      The balun system above works with any Yagi, and it even works when used with dipole antennas. My 160-meter Inverted Vee dipole has a similar balun system, with the connector grounded to the tower.

       Below, Outside Entrance Panel
      house shack ground cable entrance outside

       



      All cable shields are ground to wide copper flashing. This means there is no RF current flowing between shields inside the house.

      The wide copper flashing exits under the house directly to the mains entrance ground for safety.
      It provides a low impedance shunt to ground for any RF on shields.


       Below, Inside Entrance Panel and Common Point
      inside radio room ground entrance common point

      Left to right:
      Receiving antenna trunk selection
      Control cables
      Power SWR sample
      Antenna trunk switch




      Small green connector is receiving antenna directional control busses

       

       

      This is double protection. Any current flowing between shields is minimized before reaching the operating desk.

       Summary 

      Most, but not all, RF in the shack problems are caused by poor antenna implementation. It is best to mitigate any problem at the problem's source. Notice the cures above did not talk about the RF grounding quality. The real cure is keeping things at the same potential and keeping unwanted currents outside the house.

      http://www.w8ji.com/rfi_rf_grounding.htm

      House Ground Layouts



                                              House Ground Layouts



      Poor but Commonly Used
      Staion lightning ground very poor installation

      The most severe and frequent damage is normally not caused by a voltage difference between each conductor in a multiple wire cable, but from those conductor groups or bundles to other conductor groups or bundles. Nearly all severe lightning damage is caused by lightning currents flowing through the house wiring as common mode current.
      This first example has severe ground loops. It is a danger for many reasons. It does not protect for power line neutral faults, equipment failures, or lightning.
      With a system like this, we should plan on damage when lighting strikes anywhere near electrical powerlines or antennas.

      Drawing on Left

      This system is the most common type of wiring used by Hams and CB'ers. It has a tower ground rod or rods, an equipment ground rod or water pipe connection, and an entrance panel ground at the electric meter. It does not comply with national electrical and fire codes, because it is independent entrance grounds.
      The dashed line from the electrical service entrance panel to the radio room represents the powerline leads in the house.
      The heavier solid line represents all control and feedline cables from the antennas.
      This is a very poor setup. Lightning protection, regardless of quality entrance protection devices that might be installed, will be almost nonexistent. Common mode lightning currents, the worse kind, will simply loop through equipment to the powerline. This is true if lightning strikes on or near power, CATV, or Telco lines, or if lightning strikes on or near your antenna system.

      Better but Not Perfect

      Better station lightning safety ground system
      This system adds a wide, heavy connection (shown as a thick black line outside house) between the entrance grounds. This connection could go under the house. My bonding connection, for example, goes directly under my house in the crawl space. I use 3-4 inch wide copper flashing with no splices or bends under the house. My bonding connection is kept away from other metallic objects like plumbing, ductwork, and wiring, even though it routes right under the house.
      This bonding connection significantly reduces chances of damage from power line neutral faults and lightning strikes on the power lines or your antennas. This system meets national fire protection suggestions. (Although it is much better than the common isolated ground installations, lightning protection can still be improved.)
      The nearer the radio room entrance panel and ground is to the electrical service entrance ground, and the lower bonding conductor resistance and impedance is compared to the impedance and distance of mains wiring to the radio in the house, the better this system will work! (Remember lightning has considerable higher frequency energy, treat it like RF.)
      The dashed line from the entrance panel to the desk again represents all of the power and telephone lines.
      The lighter solid line represents feedline and control lines. It goes through a grounded entrance panel.
      The heaviest line is the bonding conductor.
      Any desk ground wire should route parallel and near the operating desk to feedline and control wire bundle entrance panel  to the feedline entrance panel. Do NOT run the desk ground directly to the station ground rod.
      Remember while this is much better and meets codes, it is still not the best configuration. A portion of common mode lightning currents will still flow through equipment to the mains ground unless the radio equipment is unplugged or disconnected from all cables and grounds going to the entrance panel, or both.

      Better For Gear but Bonding Missing
      Better ground system house amateur radio

      This is another system that significantly improves protection of the equipment at the operating desk. Unfortunately it omits the critical ground bonding necessary for full house protection. It does NOT meet national code requirements. The mains ground is not bonded to the station entrance ground.

      EVERYTHING on the desk or connected to the operating desk in the radio room has to routed from the room common point entrance to the desk. No exceptions!








      The three lines from the panel to the desk are all of the power lines, a line representing all of the control lines and antenna cables, and the ground wire.
      These lines can and should be bundled or closely spaced if possible.

      The problem? While it forms a protection zone in the radio room, the path for common mode lightning currents between the antennas and the power lines is through house wiring! This can cause a large voltage difference between electrical wires and other metallic conductors throughout the house.

      Best by Far

      Station best ground system for lightning and power line faults

      This system meets all codes. This system is nearly as good as bringing all antenna system cables and wiring in at the house utility entrance (which would be perfect).
      EVERYTHING on the desk or connected to the operating desk in the radio room has to run from the room common point entrance. No exceptions!
      The closer the radio room cable entrance is to the power mains entrance, the more effective this system is.
      The two lines from the radio room entrance ground panel to the desk include all power lines, with the medium size solid line representing a bundle of all control wires, all antenna cables and any desk grounding wire. These lines should be bundled or closely spaced.
      Everything entering the desk area, including Telco and power connections, must be routed from the radio room entrance panel common point.
      The value of the optional tower-to-station bonding conductor connection (longer dashed line) depends on distances. If the tower or antenna is near the house, it is better to bond it in. If the tower if more than 50 feet away, it might as well be isolated on its own ground because the impedance will likely be too high to be an effective bond.
      The system to the left is my basic system. Pictures are shown below.


      lighting house ground entrance



      This is my house station entrance.

      All control cables are shielded.
      All shields are grounded.
      The house is surrounded by a halo ground.







      power lines grounded to station entrance ground




      All desk power is grounded to station ground buss.













      wire hider and station inside barrier entrance

      This is my "wire hider" built to look like a window seat. A finished cover fits over it.
      All cables feed out from here in a bundle to the desk.
      Just outside the rear wall is my outside grounding point. All cables enter through a 4 inch corrugated pipe.


      under desk wiring


      Under desk. All equipment on desk feeds from common outlets, and all wiring is parallel and close.

      Without my "wire hider" I would have many dozens of cables feeding the desk instead of only several cables. The wire hider was the single best thing I ever did to clean up my desk wiring.






      w8ji station desk

      Picture January 2010.
      All this equipment runs from only several cables entering the desk area. With just a few cables I have the selection of almost 30 receive antennas, dozens of transmitting antennas, and five amplifiers (1500 watts from one sixty through six meters).
      In addition the flip of a few switches and moving two or three multi-conductor plugs to new sockets transfers all antennas to my contesting barn.

      Not only does lightning protection improve, station wiring is much more manageable.
      The Globe Scout was the first commercial transmitter I ever owned. It was bought used from WRL and arrived via Railway Express at Central Union Terminal in Toledo, Ohio. It was a gift for passing my General. Prior to that all of my gear was home brew, including my receivers. See my boatanchor page

      Go to Contest station grounding


      http://www.w8ji.com/house_ground_layouts.htm

      Basic Ground System Functions


      Basic Ground System Functions

       A ground system provides four primary functions:
      bulletTo help disperse or divert energy from lightning strikes
      bulletTo provide safety in case some problem or fault energizes the cabinet or  chassis of equipment with dangerous voltages
      bulletTo provide a controlled RF return path for end-fed (single wire feed) or poorly configured or improperly designed transmission-line fed antennas
      bulletTo provide a highly conductive path for induced or directly coupled radio-frequency currents, rather than having them flow in lossy soil
      While all of the functions above are distinctly unique, some ground systems can serve two or more functions quite effectively.
      If the antenna system has bad common mode current problems, caused by a faulty design or installation, a ground can help reduce common mode noise reaching the antenna. This is really from an antenna flaw, and not from the "reflection of signals".

      A ground screen, counterpoise, or ground radial system below the antenna can reduce local noise sensitivity by reducing the antenna's response to local noise. This would apply to a horizontally polarized antenna, because earth losses can cause the wave to tilt and have vertical response. As we all know, vertically polarized signal propagate along the earth with much less attenuation than horizontally polarized signals. Ground rods have no effect on this, it requires something that actually covers the lossy earth under the horizontally polarized antenna.

      A ground will NOT.....
      • A ground normally will not help reception. The exception is an antenna system design problem or installation problem causing the antenna system to be sensitive to common mode feedline currents. If adding a station ground helps reception or transmission, there is an antenna system flaw.
      • A ground will not reduce the chances or number of lightning strikes. A properly installed and bonded entrance ground can only reduce or eliminate lightning damage from hits.

      Lightning Ground

      Lightning is a high energy stepped waveform pulse. Rapidly changing  steps in voltage contain high frequency energy. This energy has a peak in the dozens or hundreds of kilohertz, with the bulk of energy ranging from low AC frequencies to perhaps 1MHz. Damaging energy extends to hundreds of megahertz. Lightning should be considered a dc to VHF energy source with the bulk of energy at lower frequencies. Current is massive, thousands of amperes can flow in a lightning strike. A good ground must have a very low impedance over a very wide frequency range. This rules out thin wires, and loosely woven braided conductors should be avoided. The very best ground leads are solid wide smooth surfaces, although braiding sometimes must be used in areas that demand conductor flexibility.
      Most of the time damage comes from lightning strikes on power lines. Lightning most often follows the utility lines to the house, through house wiring to equipment, and to ground in antenna systems.  The real danger is lightning flowing through the equipment and house wiring to seek a ground. Read this page link station ground
      With taller towers, lightning can be a frequent unwelcome visitor. Tall structures often require a large-area ground with low impedance, wide, smooth copper flashing or heavy gauge solid wire surrounding critical areas, such as a work area or equipment area near the tower base. Tall towers need a ground that rapidly and evenly spreads charges out over a wide area. The goal is to prevent objects near the structure from rising significantly faster in voltage than other objects located near the tower. Very high currents can flow between things near the tower,  it is important to provide a low-impedance path for these currents.
      Lightning grounds should always provide a common low impedance path between everything conductive entering a building. This means power lines, telephone lines, TV antennas, and metallic conduits or pipes should all share a common ground connection buss that has very low impedance. Normally the lowest impedance connection is provided by a wide smooth surface copper flashing, although very heavy round copper can be used. Round copper has lower RF resistance per unit length for a given surface area, but flat wide copper has less reactance and lower overall impedance. This is because fewer magnetic flux lines encircle any given area of wide strip than enclose the surface area of a compact conductor. In effect the magnetic field is "spread out", reducing inductance.
      There are many sites detailing ground connections, Polyphaser being the most accurate overall.       
      A good lightning ground is generally a good equipment fault safety ground, but it might not be a good RF ground! RF grounding sometimes requires shielding of the earth from radio frequency fields, or moving the RF energy out of the lossy soil. Lightning generally requires we connect to the earth, and freely move energy into or out of lossy soil. Certain RF ground applications require minimizing RF current flowing into lossy soil.


      Grounds at Towers

      Permanently grounded towers like Rohn 65G.
      Tower base grounding








      Each leg of the tower base is grounded to the ground system that consists of at least thirty fairly-long #16 buried bare solid copper wires.







      There is also a buried #8 AWG solid copper wire from each corner rod extending outwards.

      Soldering is "hard" silver solder, not plumbing type silver solder. It takes a MAP gas torch to melt real silver solder. The copper almost gets red hot when soldering. Silver solder is available from McMaster-Carr or from welding supply houses.
        

      Insulated Towers









      3/4-inch copper pipe at all three corners of the base plate serve as a lightning gap on my insulated base Rohn 45g tower.







        
      Insulated tower lighting gap






      The arrows point to burned marks where lighting has caused arcs across the gap.
      I bend the pipe in or out to change the gap.










      Ground buss at tower brazed to copper rods

      The ground buss of this tower has one hundred 200-ft long radials attached. The radials are #16 AWG solid tinned copper buss wire.










      Ball Gap Lightning Gap
      My 300-ft tall Rohn 55G has a ball gap at the base.
      Rohn tower insulated base


















        
      Rohn tower ball gap lightning suppressor




      This is the much preferred commercial method.









      At House
      By the way, despite having two 300-ft tall towers, four 130-ft wire verticals in a four square, a 220-ft tower, a 200-foot rotating tower, and miles of receiving feedlines covering distances up to 3/4 mile... I don't use coaxial lightning surge protectors. I have bulkhead entrance panels and use common point grounds and a few MOV's on power lines, but none of my feedlines have surge suppression devices. All of my feed and control cables stay connected during lightning storms, last count that was about 50 cables. My equipment stays connected to power mains through a main disconnect switch.
      antenna selection and disconnect





      The sole source of my transmitting antenna disconnects is an unmodified  DX Engineering RR-8 HD antenna switch.
      The case is securely grounded to the hamshack entrance ground.







      I fabricate my own copper grounding plate for use at cable entrances:
      Every cable enters through bulkhead connectors attached to a plate like those above. This plate is tied into the common ground at my station entrance. That ground is common with power line and utility entrance ground to the house.
      Despite multiple hits every year on my tall tower, I never suffer equipment damage. This is all due to my use of proper grounding protocol. Everything entering my operating room, including power line safety grounds, bonds to a single point at the entrance point of my operating tables.

      Safety Grounds

      Radios that operate from power mains stand a chance of having the power line accidentally fault to the chassis. Worse yet, a linear amplifier with high voltage power transformer might develop a secondary to primary short, and that short might cause the chassis to rise to peak secondary voltage plus peak primary voltage! An amplifier with a 2400 volt RMS transformer operating on 120 or 240 volt USA power mains might have a chassis voltage as high as 3600 volts from a secondary to primary failure inside the transformer.
      Any advice saying our equipment doesn't require a safety ground connection is very bad advice. All power mains operated amateur radio gear, especially devices with HV inside, requires a safety ground.
      The safety ground does not really need a ground rod, it actually only requires a connection back to the power mains service entrance ground though a very heavy conductor. It may be desirable to augment this safety ground connection with a few extra earthing ground rods. As with lightning grounds, any special safety ground must bond to the utility entrance ground. A good lightning entrance ground also makes a good safety ground, provided it is brought from the entrance point panel to the operating area where equipment is bonded into the ground. Do not go outside beyond the entrance panel barrier with this ground lead.
      Equipment with properly installed safety ground plugs, provided wiring and plugs are up to current codes, do not require a special safety ground connection. They are grounded through house wiring.

      RF Return-path Ground

      An antenna system using properly installed and connected coaxial or balanced lines would never require a RF station ground. All currents flowing out to the antenna would be perfectly matched by equal currents flowing back on the second conductor, be it a shield or the second identical conductor of a balanced line.
      The problem is many antenna feedpoint or feed systems are poorly designed. It is the abundance of poorly designed systems that cause problems. These flawed systems are behind notions that good Ham shack RF grounds are required to reduce TVI, prevent RF in the shack, or improve transmitting or receiving ability. The troublesome currents are called common-mode currents, because they are not normal push-pull transmission line currents found in two-conductor transmission lines, like coaxial or ladder lines.
      A few examples of antennas producing excessive RF in-shack ground currents:
      bulletEnd-fed halfwaves, including end-fed "dipoles" of all types
      bulletZepp antennas, especially those where the feedline is not an odd 1/4 wl and the antenna not a multiple of 1/2 wl)
      bulletCenter fed dipole antennas without a balun or dipoles that do not use a feedline length that minimizes common-mode current
      bulletVerticals with poor grounds or somewhat sparse grounds, including "half-wave" verticals with small or no radial systems
      bulletEnd-fed longwires, off-center fed dipoles,  or Windom antennas
      It can be truthfully said if we use a two-conductor feedline of any type and have RF in the shack problems, our antenna feed system is poorly designed or constructed. An RF ground in the shack is absolutely NOT required unless something is wrong with our antenna system. The sole exception to this is a single wire feeder, like a longwire, brought directly into the shack.
      An RF "return path" ground or antenna system ground requires low RF impedance. The ground has to spread current around over a large area. The best system uses many small diameter conductors radiating out at least 1/8th wave, and preferably further, from a central connection point. These conductors do not need to contact earth, they function simply by providing "electrical mass", or a low RF impedance, for the antenna system to push against. It is not a question of surface area or capacitance, it is a question of distributing charges efficiently over a large spatial area (large in terms of the operating wavelength).

      Induced Ground Currents

      All efficient antennas, including loops, dipoles, verticals, and beam antennas, are surrounded by very strong electric and magnetic fields. If the antenna is close to earth (in terms of operating wavelength) considerable current can flow in the lossy soil. Current flowing in lossy earth causes power loss, even when the antenna and/or ground system does not have a direct earth connection. Earth currents are especially problematic when dipoles are placed at small fractions of a wavelength above ground, or when verticals are mounted on or near the earth's surface.  
      Currents like are minimized by covering a large area of earth surrounding the antenna with many closely-spaced conductors. The conductors do not need to be any particular length, they only requirement is they extend beyond the area where field density is high. If the conductors are less than .05 wavelength apart, they can be considered a large single conductor covering the entire area. Much wider spacing than .05wl, and they allow the lossy media between the conductors to be exposed to strong fields.
      The diameter or gauge of grounding system conductors isn't important, but spacing of grounding conductors and overall length of grounding conductors are both very important!

      Isolating or Disconnecting Feedlines
      One of the best ways to protect receivers and transmitters, besides having a good ground system and cable entrance feedthrough that is bonded to the mains ground, is to disconnect the feedline from the equipment. This disconnect has to be done properly. The best location is normally away from the operating desk, right near the entrance.
      If you use disconnect relays or switches, they should be a double-make double-break style. A double-make double-break looks like this:

      isolation relay


      Lightning cannot pass through from side-to-side because the shorting bar is grounded when not energized. Any arcs across contacts would go to ground.




      As an example of a layout with proper grounding, you can see my station entrance system below:
      W8Ji station house entrance cables


      This is my house entrance. It is normally covered with a box to prevent weather and sun exposure, to visibly hide the wires, and to prevent physical damage.
      All cables are shielded and the shields are grounded outside the house. The large copper flashing routes directly under the house to the power mains entrance ground.
      Control cables are to the left, transmitting feedlines are in the middle, and receiving antennas are to the right.
      There are spare cables also.


      Inside House
      wire hider station entrance transmitting antennas

      All transmitting antennas enter through a DXE RR-8 antenna switch. The switch case is grounded through large copper flashing that ties the station power lines and receiving antennas to a common buss in the room entrance box.
      Cable shields are bonded to that buss.
      Receiving antennas are to the left, and are grounded to the same flashing.
      My station antenna disconnect is actually a DX Engineering RR-8 antenna switch. The RR-8 switch, like the Ameritron RCS-8V, provides excellent center conductor isolation whether the switch is configured to ground the center conductor or not. This is because both the DXE and RCS-8V use a double-make  double-break isolation system. I like the DXE RR-8 better because it has an all metal cabinet that is easier to ground.

        
      wire hider inside room station entrance

      This box (I pieced together two photos to show it all) looks like a window seat when the cover is on. Power and telephone entrance is on the left, receiving antennas are in the middle, and transmitting antennas are on the right. All grounds and shields are tied together with wide flashing.