Alpha Antenna/KX3

[ANDY DURBIN]

If you want a mag loop why not build one?   I had fun building mine and I made enough QSO with to have made it worth while.   As others have said they have narrow bandwidth and mine is temperature sensitive.  I got used to having to retune it as soon as the morning sun reached it.

Maybe my presentation will give you some ideas.  - http://www.w7tbc.org/downloads.php?do=file&id=369

73,
Andy, k3wyc

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[Edward R Cole]

Interesting reviews on some of the loop antennas.  I've seen W4OP
adv's for several years.

I plan to make a receive-only 630m loop (4 to 6 foot diam) out of
some surplus 1/2-inch hardline that is too old for coax use.  The
copper shield should do well in a loop.  I will use a preamp with it
(pcb in hand waiting for some spare time to build).  Plan using a
small TV rotator and tripod mount.  Advantage of the loop is being
able to null out noise sources. I transmit using 43x122 foot inverted-L.

The loop might also work for 160m if I ever try that band.

73, Ed - KL7UW
   http://www.kl7uw.com
Dubus-NA Business mail:
   [hidden email]

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[Gwen Patton]

I built a loop a few months ago, using flexible plastic pipe strap and 1/2"
copper foil tape with conductive adhesive. I used a junkbox air-gap
capacitor and a 10x vernier knob to tune it. I ran 100w through it on FT8
and ran an infrared thermometer all around it and it barely warmed past
room temperature. From inside my house in the Philly burbs, I got FT8
contacts in northern Wisconsin and Fargo, North Dakota on 30 meters, so I
think it was getting out pretty well. I was running 30 watts or so on it at
the time, as I recall. Not bad from indoors on the first floor with a steel
workbench a foot away and resting on a wire rack. Someday I'll take it on a
park run and see how well it works out in the open. I'm considering making
a better loop first though, as this one is pretty flimsy and probably won't
stand up to any significant wind. I need to redesign it for more rigidity
and probably a somewhat larger loop to get at least SOME efficiency on 40
meters and perhaps even a little on 75/80, though that's asking a lot of a
small loop.

73,
Gwen, NG3P

On Thu, Jun 6, 2019 at 12:11 PM Edward R Cole <[hidden email]> wrote:

> Interesting reviews on some of the loop antennas.  I've seen W4OP
> adv's for several years.
>
> I plan to make a receive-only 630m loop (4 to 6 foot diam) out of
> some surplus 1/2-inch hardline that is too old for coax use.  The
> copper shield should do well in a loop.  I will use a preamp with it
> (pcb in hand waiting for some spare time to build).  Plan using a
> small TV rotator and tripod mount.  Advantage of the loop is being
> able to null out noise sources. I transmit using 43x122 foot inverted-L.
>
> The loop might also work for 160m if I ever try that band.
>
> 73, Ed - KL7UW
>    http://www.kl7uw.com
> Dubus-NA Business mail:
>    [hidden email]
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

--

-+-+-+-+-
Jenny Everywhere's Infinite: Quark Time
http://quarktime.net
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[Jim Brown-10]

The RX only loop you're describing are VERY different from magnetic
loops designed for TX.

73, Jim K9YC

On 6/6/2019 9:11 AM, Edward R Cole wrote:
> Interesting reviews on some of the loop antennas.  I've seen W4OP
> adv's for several years.
>
> I plan to make a receive-only 630m loop (4 to 6 foot diam) out of some
> surplus 1/2-inch hardline that is too old for coax use.  The copper
> shield should do well in a loop.  I will use a preamp with it (pcb in
> hand waiting for some spare time to build).  Plan using a small TV
> rotator and tripod mount.  Advantage of the loop is being able to null
> out noise sources. I transmit using 43x122 foot inverted-L.
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