Comet CHA-250B Ground Rod Installation

A Quick Modification!

I recently read several articles about CHA-250B installations and realized I had not grounded the antenna as some of the articles had suggested. The CHA-250 owners manual doesn’t indicate a ground connection. I was following the owners manual when I installed the antenna. I was curious to see if it would have any effect on performance. So I bought some supplies and started the Comet CHA-250B ground rod installation. I first realized I was missing the ground connection when I found this schematic on the G8JNJ website:

CHA-250B Balun Schematic
CHA-250B Balun Schematic showing ground attached to coax shield.
CHA-250B Grounding
CHA-250B Grounding. I used hose clamps, as I did on all my other coax ends.

The ground wire is connected to the coax shield using a hose clamp. The copper wire under the clamp is doubled over, to make better surface contact. An idea I got from K3DAV’s website.

CHA-250 Ground Rod
The CHA-250 Ground Rod has two hose clamp connection points (bottom and middle)

All connections to the copper ground rod were doubled over, and clamped, to create more surface contact I’ve had success with the clamping idea, so I used those clamps again.

Results!

I run FT8 using a Flex 6500 barefoot into the CHA-250B. It puts out 86 watts. The CHA-250B does not disappoint! Over the past two days I have worked JA, UA0, 9Y, SP, OH, VK, UT, and KH6! Just to name a few! I now have thousands of FT8 contacts across 6 bands!

The antenna is a bit quieter, noticeably so on 30m, and the SWR is roughly the same on all bands. I can’t claim any big improvements. Static charge build-up, caused by high winds, will go to ground. Installing the Comet CHA-250B ground rod was definitely a worthwhile endeavor.

Update: 06/18/20

Since grounding the CHA-250 I’m noticing European stations in the FT8 monitor panel. Prior to this, I’d rarely seen any calls from the EU. Either conditions have suddenly improved, or adding the ground has made a significant improvement. With all the complaints I hear on the air about conditions, I have to believe adding this ground to the CHA-250 has caused improved performance. I’ve worked all through Europe since installing the ground.

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Author: K6HR

Licensed since 1994. Active on HF / VHF / UHF / Satellite.

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