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Receive Antennas (below 30MHz) - For all topics related to receive antennas used on HF, MW, LW, etc. For transmit antennas use the Amateur Radio Antennas forum.

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Old 10-27-2016, 10:12 AM
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Default Use a flagpole as swl antenna.

Has anyone ever used a telescopic flagpole as a swl antenna?

I have a wire antenna running from my radio to the roof with a insulator at the roof and the other end to a insulator on the flagpole. But on the top of my flagpole is a screw. I am thinking is I loosen the wire around the insulator and make a connection on the screw it would give additional reception. Am I thinking correct?

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Old 10-27-2016, 11:35 AM
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You might better answer your own question by trying it for yourself. If it boosts signals-great!
But off the top of my head, I think since the flagpole is sunk into the ground (right?) it may do better as a "counterpoise" to your wire. So you run 50 ohm coax as the feedline from the radio-the center lead goes to your wire antenna, and the braid connects to the flagpole.
As I always say-experiment.
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Old 10-27-2016, 11:39 AM
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Quote:
Originally Posted by ridgescan View Post
You might better answer your own question by trying it for yourself. If it boosts signals-great!
But off the top of my head, I think since the flagpole is sunk into the ground (right?) it may do better as a "counterpoise" to your wire. So you run 50 ohm coax as the feedline from the radio-the center lead goes to your wire antenna, and the braid connects to the flagpole.
As I always say-experiment.
Thanks ridgescan

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Old 10-27-2016, 11:40 AM
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Telescoping flagpoles might not be so sturdy in a wind or snowstorm. There might be too much sway and movement- it could cause a lot of static under the right conditions

But you won't know until you try...Mike
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Old 10-27-2016, 11:48 AM
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Originally Posted by ka3jjz View Post
Telescoping flagpoles might not be so sturdy in a wind or snowstorm. There might be too much sway and movement- it could cause a lot of static under the right conditions

But you won't know until you try...Mike
Thanks Mike

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Old 11-13-2016, 8:49 AM
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It'd be nice to have a vertical antenna as well as a horizontal. By that I mean feeding the base of the flag pole via a shunt, and keeping the wire antenna as it is. I've often had signals on hf that were detectable on one polarity but not the other, especially at fadein/out.
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Old 11-16-2016, 8:34 PM
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I once read of hams using flagpoles as antennas using a 'gamma match' (a way of matching the feedline to the pole). Even on grounded poles.

Hard to believe you could use a grounded pole as an antenna, but there are stranger antennas out there then that....
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Old 11-17-2016, 12:12 PM
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I would be interested in hearing what the OP wound up going with and how it's working out.
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Old 11-18-2016, 1:31 AM
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Quote:
Originally Posted by ridgescan View Post
I would be interested in hearing what the OP wound up going with and how it's working out.
I have not tried anything. I am just staying with my long wire. Thanks for the replies on this question everyone.

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Old 11-18-2016, 1:32 PM
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Quote:
Hard to believe you could use a grounded pole as an antenna, but there are stranger antennas out there then that....
Strange but true.....most Boeing aircraft that have HF fitted use the whole of the vertical stabiliser (that fin at the back) as the antenna and the gamma match is behind the black rubber boot on the leading edge. The whole fin is definitely bonded to the rest of the aircraft!
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Old 12-05-2016, 7:38 PM
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Well I tried adding some wire to make a connection from the long wire to the screw on the flag pole and it did not make any difference. So I have un-did it and am back to my long wire. Thanks for the feedback gang.
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Old 02-07-2017, 11:13 AM
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Quote:
Originally Posted by IL65 View Post
Has anyone ever used a telescopic flagpole as a swl antenna?

I have a wire antenna running from my radio to the roof with a insulator at the roof and the other end to a insulator on the flagpole. But on the top of my flagpole is a screw. I am thinking is I loosen the wire around the insulator and make a connection on the screw it would give additional reception. Am I thinking correct?

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When I was 13, we had these old metal light poles on our street and they were the ones that had the wire on top that went from light pole to light pole. I took a file and filed down to bare metal and taped a small gauge
wire to it. It actually worked great until the sodium lights lit up then it was all NOISE. )

So, anything can work. Just have to make due with what you have.
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Old 02-20-2017, 7:22 PM
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actually, it would make a very good "shunt fed" vertical antenna

hams have been operating shunt fed flagpoles and towers for many decades with great results
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Old 02-20-2017, 9:25 PM
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Quote:
Originally Posted by MOTEX View Post
actually, it would make a very good "shunt fed" vertical antenna

hams have been operating shunt fed flagpoles and towers for many decades with great results
I'm just curious-did they do this antenna for mainly transmit or did it actually make for a good receive antenna?
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Old 02-21-2017, 7:56 AM
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Quote:
Originally Posted by MOTEX View Post
actually, it would make a very good "shunt fed" vertical antenna

hams have been operating shunt fed flagpoles and towers for many decades with great results
Indeed, but we're talking about a telescoping flagpole - maybe 6-8 foot long. Even with shunt feeds, it won't be very efficient except on the highest HF bands - above 20 Mhz or so. Yes, it will hear things below this, but it won't work very well

You would need some sort of matching unit to make it reasonably efficient to go lower than that. And in fact, on some designs used by hams, they use some sort of matching to make the tower resonate on, say 160 meters when the tower is only about 30 foot high, even with a shunt feed

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Old 02-21-2017, 11:27 AM
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Quote:
Originally Posted by ka3jjz View Post
Indeed, but we're talking about a telescoping flagpole - maybe 6-8 foot long. Even with shunt feeds, it won't be very efficient except on the highest HF bands - above 20 Mhz or so. Yes, it will hear things below this, but it won't work very well

You would need some sort of matching unit to make it reasonably efficient to go lower than that. And in fact, on some designs used by hams, they use some sort of matching to make the tower resonate on, say 160 meters when the tower is only about 30 foot high, even with a shunt feed

Mike
Always appreciate your knowledge on these things Mike. Me, I figure a thick metal flagpole stabbed into the dirt would make a lousy receive element, but may make a nice counterpoise to a random wire. But then again, I recall K9RZZ once loading a highway guardrail
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Old 02-28-2017, 3:46 PM
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Hams using flagpoles for verticals are insulating the flagpole from the ground. You would attach radials for the counterpoise or ground side. A flag pole antenna is not just stuck in the ground.

There are several companies that make "flag pole" verticals - ZeroFive and Force 12. For example the Force 12 uses a fiberglass insulator to insulate the flag pole from the ground.

In this picture from ZeroFive you can see the green ring that is the top of the insulator.
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Old 02-28-2017, 7:16 PM
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Can't believe nobody has mentioned the widespread usage of modified flagpoles as antennas in certain ...err... covert locations....

If you know what to look for, there are very likely several in any decent sized city....
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Old 02-28-2017, 9:37 PM
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We're getting a tad OT here. The original question had to do with using a telescoping flagpole as a receive antenna; let's get back to that

It would be a tad difficult to use a matching device like that in a receive-only application, I suspect. Those devices, from what little I've seen of them, require a source of RF to cause them to tune the antenna.

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