From: Jim Brown <jim@audiosystemsgroup.com>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Raised Radial Spacing
On 10/31/2025 6:50 AM, jim.thom jim.thom@telus.net wrote:
> While
> K9YC might not like it, I think it's a viable solution.
>If you bothered to read my 160M slide deck, you would have seen my
>inclusion of a similar solution that NC0B implemented in his suburban
>driveway and published in Ham Radio about 40 years ago. He used wire
>mesh in a grass strip between the driveway and his house, and I included
>multiple slides showing variations of his solution.
>And if you bothered to read any of my writing, you would know that my
>emphasis has always been about learning what works BETTER, whether it's
>RFI solutions, common mode chokes, or antenna systems. And also about
>debunking common misconceptions. My heroes are others, like W8JI, N6BT,
>NC0B, N0AX, N6BV, and N6LF who have done the same in their own areas of
>interest and expertise.
>73, Jim K9YC
Well excuse me for not reading your 160M slide deck. That's one I missed.
You got any idea how long it takes to wade through a myriad of your info
....... months. I believe I have read just about everything you have
written, including all the pro-audio items. Toss in all the other folks
you mentioned, and it becomes an all time consuming task. It took a long
time just to wade through all the W8JI info. He still hasn't got the CM
construction done correctly, and some of his material is questionable..
A lot of N6BT's mechanical designs are severely flawed. His 40M relay box
for his 40m shortened yagi's isn't even close to reality. I have his 5 el
20m yagi. Ele center construction is flawed, as is the boom design. I
have his 6 el 15m yagi, and the boom on that had to be beefed up. I have
his 75m rotary dipole, and it too, required a complete re-design. It's
all fixable, but a major pita. I also have his 3 el, 40m yagi ( 340N) on
the 35' boom, and it's a mess, right out of the gate. The center boom
internal splice was done wrong on mine, and a major headache to re-design
and repair. The boom to ele bracket assy's are flawed, as also noted by
others. The holes in the upper 3/16" thick bracket will enlargen way too
much...while the mating 1/4" thick rect plate below it will deflect and
permanently bend downwards. That's due to the use of only one U bolt on
each side. 'Easy fix'. 1/4" plate was tossed, and replaced with 17"
long x 4" wide channel aluminum...and heliarc welded to the upper plate.
Then 2 x 316 SS U bolts on each side. The flawed ele guying scheme was
tossed, and replaced with a proper design of my own...ditto with the boom
truss.
LL rods tossed and replaced with hb 3/8" tubing coils. New Relay box
designed and built, using G2 vac relays, and 1" wide silver plated strap
coils. That was done for both the REF and DIR and DE. Now it has 4 x
tuning segments for each parasitic...and 3 x segments for the DE. Now the
gain, FB is max across the entire band. SWR is flat across the entire
band.
If NC0B buried wire mesh under a grass strip 40 years ago, I can
guarantee there is nothing left of it. The vinyl coated mesh woulda been
a better option, but was not available back then.
I'm using hb CM chokes using your cookbook #1 designs, since I have loads
of 393 teflon coax.....( I used 2 of em in series, each in it's own
Nema box). I have also experimented with the teflon version of
RG8X....with it's 15 ga center conductor...... It's a good compromise
between RG-400 and RG-393. The issue is those Fair rite cores.....
which are now made in China . The tolerance is all over the map... like
+/- 20%. . Good luck trying to find 2 that are the same.
And hats off to everybody who is trying to enhance the state of the art.
Jim VE7RF
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