[TowerTalk] 1dB more RF Power?

Thu Apr 30 15:46:54 EDT 2020

There is no question that a well matched, efficient antenna, mounted in the
clear is the best.  But my "pile-up anxiety" is practically non-existent.
I know what a pile-up sounds like from a DX station's point of reception.
For five and a half years I sat in front of a radio for 20 hours a week,
running the pileups from Kwajalein in the Marshall Islands.  From
December,1983 until April,1989, I was KX6DS.  I also operated as KC6TO from
Ponape (Pohnpei) in what was then the Eastern Caroline Islands, now
Federated States Of Micronesia. I made 83,000 QSOs and have more than
40,000 QSLs on the shelf in one of my closets to show for it.

One night on 20 meters there was propagation only between me and San Diego,
California. I had no pileups and a nice ragchew developed with me and three
San Diego stations.  they were all running 1500 watts with tribanders at 70
feet and lived within two or three miles of each other.  So I asked them to
start talking in turn, one after another, and to keep it up for several
minutes.  While they were talking I watched the signal strength of each.
One of them would be 20 dB stronger on any given round. The next sentence,
another of them would be 20 dB stronger.  It was if a
propagation "spotlight" was moving around the sky, just like the ones we
used to see from the county fair. And when the spotlight shined on one of
the stations, it was his turn to work me.
My conclusion is that if you have a decent setup and use reasonable
operating technique, you are pretty much assured of a QSO.  Keep in mind
that the DX station probably does not hear many of the callers you do. I
could put stations in the log at a rate of three or four a minute as long
as good operating technique was maintained. I also found that if I remained
calm and seemed to be reasonably efficient, the pileup behaved very
reasonably.  I never criticized anyone on the air, even if I thought they
needed a  refresher in technique or simple manners.  I did lose it one
time.  There was one fellow, whose call mercifully escapes me, who
persisted in sending his call right on top of every station I was trying to
work for several minutes.  I tried to ignore him, but he was not having
it.  I finally paused and called his callsign and asked, Are you a natural
born lid or did you take lessons?"     He never called again and his call
didn't appear in my log. (All in CW)

So that's why I don't worry about a dB.

73,

Dave, K4TO
ps -- Yes I still have the logs -- all 18 of them, spiral bound.  And I
still get requests for QSLs.  If you are in the log, you can get a card.

On Thu, Apr 30, 2020 at 3:13 PM <n6sj at earthlink.net> wrote:

> Great discussion!
>
> But personally, I think on CW your timing (call early, call late), keying
> speed (call faster, call slower), and placement of your signal in the
> receiver's passband (call high, call low) will all have a much bigger
> effect
> on being noticed and answered than a 1dB increase in RF signal power.
>
> On SSB your timing, mic equalization, enunciation, and inherent voice
> timbre
> will similarly swamp a 1dB power increase.
>
> 73,
> Steve
> N6SJ
>
>
> -----Original Message-----
> From: TowerTalk <towertalk-bounces at contesting.com> On Behalf Of
> dj7ww at t-online.de
> Sent: Wednesday, April 29, 2020 8:47 AM
> To: 'Brian Beezley' <k6sti at att.net>; towertalk at contesting.com
> Subject: Re: [TowerTalk] 40m 4el KLM - replacing linear loading with coils
>
> Physical bending of the tubing is not necessary.
> By using mounting plates with isolating Stauff clamps at the needed angle
> as
> element holders straight elements can be used.
>
> 73
> Peter
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of
> Brian
> Beezley
> Sent: Mittwoch, 29. April 2020 16:17
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] 40m 4el KLM - replacing linear loading with coils
>
> The forward gain difference between my single-coil and two-coil models is
> 0.02 dB. This is with no coil losses, whose difference might easily
> overwhelm a small directivity difference. But I restored the coil losses
> and
> got the same result.
>
> Input resistance is in the mid-20s in ohms for the single coil model and in
> the mid-40s for two coils. I had expected band-edge reactances to be about
> the same for both models and thus SWR to significantly increase for the
> single-coil model. Instead, the reactances are similar to the input
> resistances, with only a small difference in band-edge SWR for the two
> designs when each is matched at band center.
>
> I neglected to say that the AWG 5 copper-clad aluminum wire weighs 37.42
> lbs/1000' while pure copper is 100.2 lbs/1000'. 3/16" OD refrigeration
> service soft copper (0.1875" instead of 0.1815") with a 0.03" wall weighs
> 57.5 lbs/1000'. 1/8" OD is 34.7 lbs/1000'. An optimized 7.7 uH coil using
> 1/8" copper is 5.6" by 3.3" with a Q of 985. (As wire diameter decreases,
> the proximity effect that limits coil Q decreases, which enables coils that
> are smaller, lighter, and cheaper.)
>
> This describes an interesting trick for 40m Yagis:
>
> http://ham-radio.com/k6sti/owa.htm
>
> I had toyed with the idea of writing a little utility that generates wire
> segments for an element bent using dacron lines that run from somewhere
> near
> the half-element midpoints back to the boom. This would eliminate the need
> for a custom bent-element mount. You could even run the lines between
> driven
> element and reflector to bend both, which may improve gain even more. To do
> this right you need the taper schedule and tubing bending parameters. Even
> better would be to include the dacron line tension in the optimization
> parameters and then optimize everything simultaneously. I'll leave this for
> someone else.
>
> If you think the 0.5 to 1 dB a conventional OWA costs in forward gain is
> inconsequential, check this out:
>
> http://ham-radio.com/k6sti/pileup.htm
>
> The analysis isn't definitive. But the next time it takes forever to bust a
> pileup with your OWA, you may not be able to get the probability curves out
> of your head.
>
> COIL 3.90 is here:
>
> http://ham-radio.com/k6sti/coil.zip
>
> Brian
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