Study notes on "Counterpoise" and my Chameleon EMCOMM II Portable Antenna


I learned this word "counterpoise" from the user manuals of my antennas.

Out of curiosity, I Googled for "counterpoise" and find a lot of information about this. According to the wiki entry, "counterpoise" is defined as following:

In electronics and radio communication, a counterpoise is a network of suspended horizontal wires or cables (or a metal screen), used as a substitute for an earth (ground) connection in a radio antenna system. It is used with radio transmitters or receivers when a normal earth ground cannot be used because of high soil resistance[1] or when an antenna is mounted above ground level, for example, on a building. It usually consists of a single wire or network of horizontal wires, parallel to the ground, suspended above the ground under the antenna, connected to the receiver or transmitter's "ground" wire.[2] The counterpoise functions as one plate of a large capacitor, with the conductive layers of the earth acting as the other plate.

So the TL;DR is that counterpoise is the grounding for the radio antenna system. The most common counterpoise forms a plane that can behave like a large capacitor. This does not seem to be the same on my antenna's manual where a counterpoise "wire" is required when the coaxial cable is not long enough. 

 For my CHA ECOMM II antenna, "counterpoise" is marked as optional if the coaxial cable from the feed point to my transceiver is long enough (50~ 100 feet) which happens to be my case. Thus I chose to ignore this "counterpoise" thing for my setup at the beginning.

During my first few days of operations on FT8 (20m, 40m), it seemed to me that my rig has had inconsistent performance. For example, I could have QSO with someone in Japan, Fiji, U.S. Virgin Islands but I also have had trouble to complete the message exchange with someone in US like Texas and Pennsylvania where I can see the other parts send over the signal report and I transmitted R-XX back but the R-XX simply got lost and eventually the other party started CQ again.

There could be many causes from antenna, to tuner, to weather, to time of the day, etc etc. My mind turned to the easiest thing that I can add to see if the situation can be improved - adding the optional counterpoise. 

The material is ~25 feet of the "Amazon Basics 16-Gauge Speaker Wire Cable" and a simple ring type connector connected to the balun of the CHA ECOMM II antenna. Unfortunately, this has not really improve the situation. I successfully had QSOs with 3D2USU in Fiji and some new HAMs in Japan again with the counterpoise installed. However I am still having the same problem that I can start the FT8 message exchange with someone on the east coast or mid-west US but cannot finish the message exchange because many stations could not seem transmission of R-XX after the conversation started. Thus the conclusion is, unfortunately, counterpoise is not the root cause of my problem. I am still very happy that I learned a new thing and applied to my practice. I will keep on trying on other factors to see how I can solve the problems I am seeing and may create another post to have some notes about it when the problem is truly fixed. 

73

References

  • Definition on Wiki: https://en.wikipedia.org/wiki/Counterpoise_(ground_system)
  • http://www.cqdx.ru/ham/new-equipment/chameleon-emcomm-ii-portable-hf-antenna-antenna/
  • Chameleon Antenna Counterpose Kits on DXEngineering.com: https://www.dxengineering.com/parts/cha-counter-kit?seid=dxese1&gclid=CjwKCAiAm7OMBhAQEiwArvGi3NnliLBE4LySlWvQSn6KvtKWzBADMSAjD8oaUUXrXl-ZVF4B41h4uxoCcs8QAvD_BwE and the user manual

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