Converting exisiting Flagpole into Antenna

[tower06]

I'm completely novice at this and trying to gain as much info as possible. Is it possible to take an existing aluminum flag pole and modify it to use as a antenna. I am looking only for MURS transmission at present an already have a flag pole on my property. My town is a pain when it comes to zoning, so I really don't want to put up with the headache of having to get all the necessary paperwork to put a stand alone antenna on my property. I figure If I can utilize the flag pole for dual use and it will effectively be hidden that's my best bet.

 

[prcguy]

Aside from adding a non conductive tube above the flagpole to hide an antenna, about the only thing I can think of is making a few feet at the top into a J-pole. About 3/4 wavelength (at MURS freqs) down from the top of the pole you could have a 1/4 wavelength conductor grounded to the pole at the end away from the top, then find the point to attach coax to the 1/4 section and flag pole where the match is best.
prcguy

 

[tower06]

Aside from adding a non conductive tube above the flagpole to hide an antenna, about the only thing I can think of is making a few feet at the top into a J-pole. About 3/4 wavelength (at MURS freqs) down from the top of the pole you could have a 1/4 wavelength conductor grounded to the pole at the end away from the top, then find the point to attach coax to the 1/4 section and flag pole where the match is best.
prcguy

Would either of these inside the pole work?

Dual Band VHF UHF Base Antenna Ham Commercial Murs GMRS FRS DBJ 1 | eBay

Tram 1491 143 173 MHz Base Repaeater Antenna 7 8 DB Gain 2 Meter Murs 3YR Warr | eBay

 

[popnokick]

If the pole was not metallic, sure. But you wrote that it was aluminum, so an antenna inside the pole will not work. The grounded metal pole will act as a radio shield and block most if not all of the radio signals from getting to / from the antenna inside the pole.

 

[popnokick]

I'm completely novice at this and trying to gain as much info as possible. Is it possible to take an existing aluminum flag pole and modify it to use as a antenna. I am looking only for MURS transmission at present an already have a flag pole on my property. My town is a pain when it comes to zoning, so I really don't want to put up with the headache of having to get all the necessary paperwork to put a stand alone antenna on my property. I figure If I can utilize the flag pole for dual use and it will effectively be hidden that's my best bet.

Do you have a roof? Does it have any vent pipes on it? I'll bet another vent pipe would go unnoticed. Check out the Ventenna here (the VT-150 covers MURS) -
Untitled

 

[AZScanner]

Hahaha, radio nerd humor (from the Ventenna website): "Two antennas met on a roof and got married.
The ceremony wasn't much, but the reception was terrific!" :lol:

-AZ

 

[tower06]

If the pole was not metallic, sure. But you wrote that it was aluminum, so an antenna inside the pole will not work. The grounded metal pole will act as a radio shield and block most if not all of the radio signals from getting to / from the antenna inside the pole.

And I assume using the pole as an antenna is a no go.

 

[tower06]

Do you have a roof? Does it have any vent pipes on it? I'll bet another vent pipe would go unnoticed. Check out the Ventenna here (the VT-150 covers MURS) -
Untitled

Vent is not a bad idea.

Thank you.

 

[Ed_Seedhouse]

And I assume using the pole as an antenna is a no go.

Pretty much if you want to use VHF. The wavelengths are short, the antenna will be quite directive but in the upward direction. For transmitting the SWR is vital, and you won't be able to get a good SWR unless you are extremely lucky,

For HF it might work but will require the addition of a radial field.

 

[prcguy]

My #2 post above would make the top 3ft or so of the metal flag pole into a VHF antenna.
prvguy

And I assume using the pole as an antenna is a no go.

 

[SCPD]

There's some possibilities here.

If it was me, I'd make a sleeve dipole out of a piece of coax, and either run it up the center of the flagpole, or run it up the side. Paint the radiating part of it white so it's un-noticeable. If you gotta go up the side, paint the coax silver, or whatever color the pole is. Or if you gotta go on the outside, maybe paint the whole flagpole white after you've put the coax on.

The radiating portion of the dipole would be about 18". All but the top 18" goes below the top of the flagpole. Should not be noticeable if you do a good job at it. Anyone notices, tell 'em it's a lightning rod, your insurance company gave you a discount for using one.

 

[tower06]

There's some possibilities here.

If it was me, I'd make a sleeve dipole out of a piece of coax, and either run it up the center of the flagpole, or run it up the side. Paint the radiating part of it white so it's un-noticeable. If you gotta go up the side, paint the coax silver, or whatever color the pole is. Or if you gotta go on the outside, maybe paint the whole flagpole white after you've put the coax on.

The radiating portion of the dipole would be about 18". All but the top 18" goes below the top of the flagpole. Should not be noticeable if you do a good job at it. Anyone notices, tell 'em it's a lightning rod, your insurance company gave you a discount for using one.

That sounds like what I am looking for. Any good references you would suggest for instructions on how to do that?

 

[SCPD]

It's early

That sounds like what I am looking for. Any good references you would suggest for instructions on how to do that?

Out of the stuff I found real quick on the net, here's about the best pic I could find. (don't use the lengths in the picture).

http://www.qsl.net/va3iul/Antenna/Wire Antennas for Ham Radio/47-Vertical_Sleeve_Antenna_for_10m.jpg

Basically, take about 20" of outer insulator off the end of a piece of coax, without nicking the outer braid.
Push the braid back over the coax, so it looks like in the picture.
The center conductor will be about 19" long. Nip at it about a half inch at a time until you get a good match.
You don't need to trim on the outer conductor after you've folded it back. In my opinion, it works better if it's about 10% longer than the center conductor anyway. Just trim the center conductor to match.
Cover with heat shrink, make sure water can't get in the end, a little dab of rtv in the end before you put the heat to the shrink, and you're good to go.

There's probably better pictures and descriptions on the net, but it's early yet.

These also make great rubber duckie antennas. I use a setup like this on my 440 Trbo handheld. Great gain. I've also used these on forklifts at work. No more breaking off an antenna 'cuz they didn't raise the door high enough.

 

[AnikF1R]

Here's my Ventenna. It's a quarter-wave ground plane cut for the air band atop a PVC pipe painted silver.