[amsat-bb] Re: Simple 2.4Ghz helix plans?
kl7uw at acsalaska.net
Sat Oct 31 08:56:49 PDT 2009
A comprehensive FAQ with a good search engine linked from the Amsat
webpage would serve well. I know you want me to do it. Sorry, I
don' t have the computer skills. But if such were to exist, when
someone new asks one of the standard questions then all you need is
to refer them to the FAQ (and anyone else reading the mail can also
look for themselves). If the FAQ does not completely cover the
question that a reader has - - then come back and ask on the -bb.
Many good "new" questions come up and can be handled, here, so I do
not think a separate forum list is needed. I already read about 8
lists as it is. Those that often answer certain questions could
submit the item to be included in the FAQ. (i.e. I would offer noise
figure and preamp answers). Others, might offer answers on "fixing
the Yaesu az-el rotor" or software questions, Doppler tracking,
Transponder on the Moon, what happened to AO-40, etc.
my two cents.
At 11:47 PM 10/30/2009, Andrew Rich wrote:
>You know this amsat-bb needs to collect up all the info and make a forum web
>Same old info over and over
>----- Original Message -----
>From: "Greg D." <ko6th_greg at hotmail.com>
>To: <mat_62 at netcommander.com>; <amsat-bb at amsat.org>
>Sent: Saturday, October 31, 2009 5:15 PM
>Subject: [amsat-bb] Re: Simple 2.4Ghz helix plans?
> > Hi Michael,
> > I followed instructions from Howard Long, G6LVB, posted here a few
> > years ago. (If the archives go back far enough, it was in November of
> > 2001). I don't have it electronically, but the instructions went
> > something like this:
> > Get a long piece of thick bare copper wire (#10 is what I think I used),
> > and
> > put a small mark on it every 5 3/4 inches (146mm). Sharpie marker works
> > well. Wrap it around a
> > cardboard tube that's about 1 3/4 inches in diameter. The tube from a
> > roll of paper towels works fine; the dimension is not critical. Space the
> > turns about 1 1/4 inches (32mm) apart.
> > Now, here's the magic part: once you get the helix about right, sight
> > down one edge, and you'll see those 146mm marks you made in the first
> > step. Twist and stretch the coils so that they all line up, AND at the
> > same time, keep the turns spaced (center to center) 32mm apart. Take your
> > time. The diameter of the turns will take care of itself.
> > For the first 1/4 turn (the matching section), decrease the pitch so that
> > it gently slopes away from the reflector, which needs to be something
> > around 4 or so inches in diameter. The rest of the mechanical stuff you
> > can pretty much make up yourself. There are a lot of examples if you
> > browse around the web a bit.
> > Helix antennas are pretty forgiving in construction, and really cheap to
> > make.
> > Greg KO6TH
> > p.s. If you already have a Wi-Fi antenna, it should work too.
> > Conversely, I've found that a Helix easily outperforms those "Pringles
> > can" Wi-Fi antennas that were popular a few years ago, in a Wi-Fi
> > application.
> >> Date: Sat, 31 Oct 2009 00:03:02 -0400
> >> From: mat_62 at netcommander.com
> >> To: amsat-bb at amsat.org
> >> Subject: [amsat-bb] Simple 2.4Ghz helix plans?
> >> I threw this out there on the eham satellite forum looking for answers
> >> but I'll try here too.
> >> I'm looking for some fairly simple plans for this antenna. Everything I
> >> find either seems to be intended for WiFi or if it is ham related is
> >> full of mathematical formulas to figure length, diameter, spacing etc.
> >> Math was never my strong suit so I'd prefer to find something with the
> >> actual already computed dimensions clearly stated. Preferably in English
> >> rather than metric measurements. I found an article in the May/June 2008
> >> AMSAT Journal that looked promising but there are no hard numbers, just
> >> the formulas and I don't have a calculator capable of some of the
> >> computations, much less being able to work them out in my head. Been a
> >> long time since I was in school!.. hi hi... I have a downconverter I'm
> >> not sure even works and I don't want to spend a huge amount of time and
> >> trouble to be able to test it.
> >> Tnx and 73,
> >> Michael, W4HIJ
> >> _______________________________________________
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73, Ed - KL7UW, WD2XSH/45
BP40IQ 500 KHz - 10-GHz www.kl7uw.com
500-KHz/CW, 144-MHz EME, 1296-MHz EME
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