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Old July 24th 11, 11:52 PM posted to rec.radio.amateur.antenna
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A Ham buddy 's son just got his General ticket, and asked for my
assistance in making a surprise contact with his Dad for his first HF
QSO. He had bought a nice 100W HF rig with an auto tuner, and an
40M-10M coax fed multi-band doublet antenna that was to be put in his
attic initially. He lives about 100 miles from his Dad.

I thought this was really cool, so I said I would set the whole thing
up. Suggested 80M early evening for that distance would be best bet.
He told me the auto tuner would not tune the 40-10 antenna on 80M
(5to1 SWR). He then asked (here is the magic part) what he could do in
1 hour to get the antenna to tune on 80M.

I told him to short the 40M loading coils, and add enough Home Depot
wire to each end so that the auto tuner was happy. He had a 100'
extension cord that he cut up and got the auto tuner happy 1.5 swr.

At QSO time he could hear neither his dad or myself, and we gave up.
Not to be discouraged he removed the shorts and additional wire, the
tuner provided a 5:1 swr, and he had a nice QSO with his dad. He also
stated he heard a lot more signals than before.

Other than the obvious (he was mistaken in what he reported to me) any
ideas as to what went wrong? I don't think he will ask for any more
advice from me.

Gary N4AST
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Old July 25th 11, 04:00 AM posted to rec.radio.amateur.antenna
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On Sun, 24 Jul 2011 15:52:08 -0700 (PDT), Gary
wrote:

the
tuner provided a 5:1 swr, and he had a nice QSO with his dad. He also
stated he heard a lot more signals than before.


Which goes to show that power is not necessary for communications. (If
at 5:1, you are still getting half the power out into the Ęther. Let's
call it 10:1 - that's still 30W out across 100 miles.) Nevermind the
smoke.

Other than the obvious (he was mistaken in what he reported to me) any
ideas as to what went wrong?


You mean the shorted coils and the extra wire? (Maybe he should have
turned it off, and then back on again - Oops, standard IT advice.)

Haven't a clue.

I don't think he will ask for any more
advice from me.


Time will tell.

73's
Richard Clark, KB7QHC
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Old July 25th 11, 05:11 AM posted to rec.radio.amateur.antenna
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On Sun, 24 Jul 2011 15:52:08 -0700 (PDT), Gary
wrote:

Other than the obvious (he was mistaken in what he reported to me) any
ideas as to what went wrong?


You forgot to offer burnt offerings to the radio propagation gods.

I don't think he will ask for any more
advice from me.


80 meters at 100 miles is in the range of the NVIS propagation. 25
miles is about the limit for 80m ground wave, and 300 miles is about
where sky wave starts. The problem with NVIS is that it's really
picky about the height of the antenna above the ground. I don't have
very much NVIS experience to offer any guaranteed suggestions on how
to make NVIS work reliably. I assume the kid will be talking to his
father regularly. My limited and unscientific tinkering empirically
determined that the NVIS horizontal antenna wire has to be fairly
close to the ground. A dipole that close to the ground has a fairly
low impedance. See "height above ground" section:
http://www.w0ipl.net/ECom/NVIS/nvis.htm
My guess(tm) is that with the antenna near the ground, most of the RF
goes straight up, which is what you want for NVIS, while an elevated
antenna delivers more RF towards the horizon. There are plenty of web
sites expounding on NVIS antenna and propagation worth reading. Tell
the kid what you think happened, but let him do the research and
tinkering.



--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
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Old July 25th 11, 03:39 PM posted to rec.radio.amateur.antenna
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On Mon, 25 Jul 2011 05:56:43 +0000 (UTC), Owen Duffy
wrote:

Next thing, someone will market a happiness meter, an SWR meter rebadged
and rescaled with a percentage happiness factor.


Sorry, but that would be prior art:
http://cybraphon.com/process/the-emotion-meter/
http://www.flickr.com/photos/cybraphon/3789780162/in/pool-917701@N24/
http://en.wikipedia.org/wiki/E-meter
I worked on something similar for the audiophile industry, when I
invented an ambience and presence meter.

Personally, methinks the correct solution for such technical problems
is to virtualize everything and eliminate the antenna and radio:
http://www.hamsphere.com
http://qsonet.com/programs.html
With these, you can have all the frustration of DX, without the
expensive equipment and temperamental ionosphere.

Do try to have a better day (as measured on the emotion meter).

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558


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Old July 26th 11, 04:37 AM posted to rec.radio.amateur.antenna
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"Jeff Liebermann" wrote in message
...

snip

I worked on something similar for the audiophile industry, when I
invented an ambience and presence meter.


I was a Navy tech at a base in the Philippines in the early 1960s. Late one
night (we were a 24-hour operation) with nothing much happening, one of the
operators was in my shop, goofing with an ohmmeter. He picked it up and
squeezed the leads, deflecting the needle some.

I don't know what possessed me but I told him to press the leads to his
temples. It deflected a bit more. I explained that he had less resistance
in his head than in his whole body, and declared him "smart" for that
reason. Well, he got the joke immediately and we laughed about it.
However, it didn't stop him from parading a goodly number of the watch
section into my shop for Intelligence Testing. Oh, my!

"Sal"


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Old July 27th 11, 01:00 AM posted to rec.radio.amateur.antenna
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The modern explanation to modern hams is that an antenna tuner is there
to keep the rig "happy". Modern folk are very busy people, they just
don't have time for understanding, but personification of these
inanimate things is apparently appealing.

Your anecodote demonstrates though how inadequate that explanation is,
whether happy rig or happy ATU.

I understand your feeling that your pride has taken a bit of a dent.
Well, part of the territory when predicting antennas eh!


The whole idea was to get the Kid on the air, and excited about Ham
Radio, by making his first HF QSO with his Dad.

I think the learning will come later-he is a Patent Attorney-EE and
Law degree. He impressed me Field Day when we were on an Island on a
lake in South Carolina on 900 watt generator power. Had a lot of
Impulse noise on RX even tho we were miles from power lines. Decided
it was from the SMPS powering the Computer we were using for logging.
The batteries on the Computer were good for ~1 hour, so we could not
disconnect the SMPS for long.

While we were fretting over what to do, he butchered up a spent beer
can, and enclosed the SMPS, dropped the noise considerably, I was
impressed.

I hope he enjoys Ham Radio, in spite of my questionable advice.

Gary N4AST

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Old July 27th 11, 04:48 PM posted to rec.radio.amateur.antenna
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On Tue, 26 Jul 2011 17:00:05 -0700 (PDT), Gary
wrote:

I hope he enjoys Ham Radio, in spite of my questionable advice.
Gary N4AST


Think of the experience in a different way. If ham radio propagation
were predictable and consistent, it would not be any fun. Just pickup
the microphone, set the controls, and talk to anyone in the world.
Kinda like a cell phone. It's the vaguarities of propagation, the
magic of sub-optimal antennas, and the mysteries of operation that
make ham radio fun. Considerable expense and effort, on the part of
major players and governments, to obtain reliable HF communications
has not been very successful over the years. Possibly "reliable HF"
is an oxymoron. Welcome the "kid" to the magic part of ham radio and
suggest that he adjust his expectations accordingly.

Incidentally, I usually carry a folded wad of aluminum foil for
improptu RFI/EMI shielding, probably because I don't drink beer.


--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
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Old July 28th 11, 12:49 AM posted to rec.radio.amateur.antenna
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On Jul 27, 10:48*am, Jeff Liebermann wrote:
On Tue, 26 Jul 2011 17:00:05 -0700 (PDT), Gary
wrote:



Incidentally, I usually carry a folded wad of aluminum foil for
improptu RFI/EMI shielding, probably because I don't drink beer.


Good comments Jeff, I will keep them in mind next time I talk to him.

Too bad you don't drink beer, the "Learn by destroying" gets really
easy after a couple. Or maybe it is just the destroying that gets
easier.

Gary N4AST


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Old July 28th 11, 06:31 PM posted to rec.radio.amateur.antenna
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On Wed, 27 Jul 2011 16:49:59 -0700 (PDT), Gary
wrote:

Too bad you don't drink beer, the "Learn by destroying" gets really
easy after a couple. Or maybe it is just the destroying that gets
easier.


Well, the slogan is not quite what it seems. I was graduation from
Cal Poly Pomona back in the days when the skool slogan was "Learn By
Doing". The basic education plan was to get as much hands on
experience for the undergrads as possible. We modified the slogan to
"Learn by Destroying" which had more than a little truth to it. I
discovered quickly that the easiest way to understand how something
works is to (accidentally) break it, and then desperately attempt to
fix it before I'm discovered. It's a great way to learn, but does
tend to get rather expensive. A less drastic version is sometimes
called "sensitivity analysis" where one uses or installs a device in
some manner in which it was never intended to function in an attempt
to see how sensitive it is to installation and operation creativity.
This works well with antennas, where there are almost an infinite
number of ways to do it and still have it function.

We have some local hams that have never removed the screws from their
radios and looked inside. I often do this for them, while they
complain about warranty and loss of resale value. Tearing the radio
apart and giving them a tour of the guts (sometimes at radio club
meetings) is also fun (to watch them sweat).

You now have the unenviable task of acting as mentor to this new ham,
who apparently has the potential for more than minimal understanding
and knowledge. You may soon find yourself doing some furious reading
(or Googling) in order to just keep up with him. I've done this a few
times, where my usefulness eventually ends when the new ham tells me I
don't know anything. I just smile, and await the next victim.


--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558


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