[HBQRP] 4 BTV also

[Piatt, Darwin]

Hi Steve..
Well this will be a long answer. I have 4 radials and they run N/S and E/W, and I want more.
Now some history..

Back in my Air Force days, the MARS station commander (a captain) was a HAM and a friend. We did some experimenting with verticals as a project for the MARS station.  In a really big field, we put a full size 20 meter vertical on the ground with feed point very close to the ground and one 8 foot ground rod driven all the way down except for maybe 2 inches. We attached a strap to the ground rod and the antenna mount. We put a field strength meter on a ladder about 100 yards away. And then we tuned the antenna and measured the signal strength for each test. We started with no radials, then went to 2, then to 4 then to 8 then to 16 then to 32 and finally to 64 (we ran out of wire). Each time we doubled the number of radials we has an increase in signal strength. We always got a good match because of the tuner, but the radiated signal got better with each increase of radials.  Our conclusion was that the antenna was more 'efficient' with more and more radials. This finding agrees with lots of stuff out on the web.

Now for fun, we put a 14AVQ (40 - 10 meter) out there and more of less discovered that as long as you had 'several' radials that were at least as long as the vertical was high, we had basically the same results. At one point we had 4 radials cut to 1/4 wave for each band (40, 20, 15 & 10) (32 radials). Then we put 32 radials that were the same length as the vertical was tall. The field strength meter showed no real difference. 

Conclusion? Just put a bunch of radials out there, at least as long as the vertical is high and go for it. (remember, if you will, that a multi band vertical is only a 1/4 wave on 10 meters, it is short on all the other bands because of the coils). 
One odd thing we noticed was that we had to keep them matched, in other words, do them in pairs. The vertical seems to get a little 'directional' if there are more radials on one side than the other.

I seem to have less noise with the radials than I did before and although I've made no real scientific measurements, my brain tells me my receive side is better now.

I'm thinking there is a basis of good reasoning why the FCC requires commercial radio stations to have 128 radials.

See ya all on Saturday after the Flea Market.

De W9HZC - Dar...


-----Original Message-----
From: hbqrp-bounces at mailman.qth.net [mailto:hbqrp-bounces at mailman.qth.net] On Behalf Of ssellmeyer
Sent: Thursday, September 08, 2005 9:25 AM
To: Midwest Homebrewers Group
Subject: [HBQRP] 4 BTV also

I've got a Hustler 4 BTV also mounted in the backyard. Tried to center it in the middle of the backyard with all the chain link fence,
flower beds, power lines, garage, house etc. Have yet to put down radials as I could only run them north/south. Garage to the west and flower beds to the east. The grass eventually grew over the RG-8 cable that was exposed. I'm sure it would grow over radials too if "pinned" down with coat hanger hooks.

I drove a 4 foot piece of pipe into the ground about 3 feet to mount it on leaving 1 foot above ground. This will be it's 4th year and have had no problems with the wind. I've watched it during thunderstorms and gusts and it just sways a little but nothing serious. I've read several postings on various mail groups that say.........if you can't put down at least 120 radials, you are wasting your time. I certainly question THAT statement. 

Dar, I'd be interested in knowing if only 4 radials made a noticeable difference. I could always "sneak" a couple thru the flower beds while she is at work someday. Have often thought of 4 each for 20 and 40 meters. "Oh look dear, your flowers are putting out nice, new, green runners (color of insulation) for next year."     What say ????



Steve/WBØQQT
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