Antenna Coax Grounding

Antenna Coax Grounding

After completing the snap on ferrite installation yesterday I began reading through a couple of new grounding documents I found online. The first to catch my attention was the article Grounding is key to good reception (by IW5EDI) This got me looking in the right direction toward antenna coax grounding and surge protection.

One of the benefits of installing all the ferrite chokes is an electrically quieter operation. Additionally, one of the biggest “wow’s” for me about the Flex 6700 is how quiet the receiver is. It’s incredibly quiet. So I’m very interested in any additional techniques that may enhance station grounding and/or improve receiver performance.

Antenna Surge Protectors

I’ll be adding several antenna surge protectors to my shopping list. I plan to have every antenna protected by a grounded surge protector and have included these in the current upgrade agenda/budget.

In the meantime there’s no reason to delay the grounding of the coax shields. I was looking for coax grounding kits or accessories and found the article The Simple Antenna Grounding System (by K3DAV) . Shown below: K3DAV’s clever solution using hose clamps and a solid copper ground wire connected to a ground rod below.

K3DAV Quick and Simple Ground Clamp Solution
K3DAV Quick and Simple Ground Clamp Solution

When I rack mounted all the equipment I installed a breakout panel on the back to provide some strain relief and keep the antenna coax leads in an easy to service position.

K6HR Antenna Breakout Panel
K6HR Antenna Breakout Panel

I used bulkhead connectors and have a very similar physical arrangement to K3DAV’s on the rear of the panel.

K3DAV's Grounding Solution will be applied across these coax connectors
K3DAV’s Grounding Solution will be applied across these coax connectors

I already have enough of the right size hose clamps, so I’ll only need to purchase a piece of copper wire at Lowe’s and this will be ready to implement. I’ll clamp the copper wire to each connector and tie it directly to the stations single point ground.

This will remain in place until I can obtain the proper surge protectors.

Worth the effort

K3DAV Grounding tip as implemented at K6HR
K3DAV Grounding tip as implemented at K6HR

I made a quick run over to Lowe’s and bought a piece of bare 8 gauge solid copper wire. I decided to install it on the outside of the panel for convenience sake. Once I get the surge protectors, I’ll probably flip it over to the inside since it’s already fitted.

It went in fairly easily. I used a pair of pliers to get all the bends right. It’s not visible in the photo, but the ground wire (exiting in the lower left corner) is tied directly to the Station’s single point ground system.

Non-Scientific Results

Before I attached the coax ground lead I took careful note of the S-Meter reading at a quiet (unused) frequency on 40 meters. Using a  2.7 khz passband, the S-Meter read a steady S4 with an occasional drop to S3. After connecting the ground wire, the meter readings indicate a steady S3 with an occasional bump up to S4. So maybe there is some very small improvement in the noise level. Hi!

Of course the noise level changes during the day etc. so this is admittedly nothing more than optimism! No measurements to back up my ‘claims’ whatsoever. But man, is this 6700 radio quiet or what! Sometimes I can’t even tell if it’s muted or not. Signals just come right up out of nowhere! It’s amazing! If I were to move this station out to a rural environment it would probably read an S1 noise level.

Another thing I notice is I no longer hear the PC speakers hum when the packet radio system transmits a packet. It could be annoying when a packet user would connect and a bunch of packets would start TX’ing resulting in a lot of short bursts of hum. This problem is no longer occurring.

The best $7.00 I’ve spent in a while.

Back To the Front

Author: K6HR

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

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