eHam
eHam Forums => Antennas, Towers and more => Topic started by: ONAIR on March 22, 2023, 05:11:17 PM
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Looking for a good field antenna for POTA! Thanks.
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With 9:1 unun I have great results with 41 ft and 55 ft wires with short counterpoise on ground. Toss it over a tree. Carl, N6TTV.
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Allegedly, the radiation pattern for the 44' doublet is somewhat predictable and broadside to the axis of the wire for 10m through 40m.
If you don't run the balanced feed line directly into a tuner, you will need a 1:1 balun and a short run of coax to the tuner. My limited understanding of this antenna is that you may need to tweak the length of the balanced line to make the system happy.
I have a 44' doublet up in my pine trees, and it works fairly well. I'm using a 1:1 current balun at the end of the balanced line with coax running to a manual tuner.
For POTA, a random wire and 9:1 transformer + tuner might be a little easier to handle.
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Depends on the band, height, distance you want
to cover, available supports, and other factors.
The 44’ doublet is a bit short for good efficiency
on 40m, which also depends on the tuner you use.
But the radiation pattern is more predictable.
I’ve used end-fed wires and they can make contacts,
but performance depends on the ground system,
and the radiation pattern is highly dependent on
how they are installed. With a straight vertical
wire, radiation may not be in useful directions,
especially above 20m.
Eventually I switched to dipoles / inverted vees
for each band on a common feedpoint, which makes
maximum use of the available height and doesn’t
require a tuner. I find it is easier and works better.
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Looking for a good field antenna for POTA! Thanks.
I used to have a MA-85 US tower trailer with a 3 element SteppIR on top. Worked very well.
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40M EFHWA, offers 40, 20, 15 and 10M. No tuner/tuning, one hose to the radio. Deploy as a flat top, vee or vertical. It's my go to antenna for portable/camping.
Mark K5LXP
Albuquerque, NM
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Feed a 44ft doublet with around 21 feet of window line and a 1:1 balun on the rig side of the window line.
14 gauge is better but the common 18 gauge window line will work with worse SWR matching.
It is quite possible to get a low SWR on both 10 and 20. The tuner will allow 40M operation.
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Greg, kc3seg, has been doing a lot of POTA locally, and the rules vary a lot. Some allow hanging wires, some do not! So planning is needed. Have at least one self supporting/self contained antenna available. Ground stakes and/or guys may not be usable... each park is different.
Investigate before arriving.
And have fun... he is!
-Mike.
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Extend the length out to about 51 ft, connect 16 ft of 450 ohm ladder line and you have a G5RV Jr that works well on 10-40m. Transition to coax and finish the run at the transceiver.
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I use a 41 foot random wire with a 4:1 unun. Works great.
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ONAIR what is your callsign ?
Bob
K6UJ