Posted: 6/15/2011 6:16:32 PM EDT
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Was poking around over on the Tactical Gear forum and saw a picture of a radio with antenna on an extension that would allow the antenna to be relocated to the top / back of a backpack. Where can I get a cable like this or how hard is it to make one? If made, what would I need as far as cable and where would I get SMA connectors / how hard is it to attach SMA / does it take voodoo magic to make it work? Pic in question:  Also, found this: http://radiowavz.us/html/mbitr_tvas.html and was wondering if there's anything like this for 2M/440. Thanks! |
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Not sure what antenna that is.
Some Ideas here in this thread, 'Source for SMA cable CHEAP?' |
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looks like a very flexible HT antenna I had thought about doing a wearable antenna but never did it.... tag for interest
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It's pretty trivial to make something like that, you just have to be able to put connectors on the cable. If you extend an antenna away from the radio sometimes you get issues with counterpoise but that can be overcome with an overbraid counterpoise.
In the past I've made a similar kind of antenna setup using wire inside a flexible pipe or hose, just hardwired to a piece of coax with appropriate length and connector to connect to the radio. Something similar could be made with the appropriate connector on top to use a rubber duck. A few years back I worked on a wearable low profile VHF low band antenna design for a deployed arfcommer, but was not able to get access to needed mil gear and test equipment to fine tune the design and test its RF performance so that project was never completed. |
| You can make one from the coax itself, and you don't need a ground plane. I've made one and it works fine. coax bazooka |
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Quoted:
You can make one from the coax itself, and you don't need a ground plane. I've made one and it works fine. coax bazooka I kind of chuckle sometimes about all the enthusiasm for the roll up j poles and such, when this has similar performance and is much easier to make. If you have ferrites handy there is an even easier way to make that, just use the ferrites to terminate the "dipole" instead of trying to fold the braid back. Can also move them up and down on the coax to fine tune the resonance. |
| That's a good friend of mines gear pic there. The antenna is this:Diamond SRH40A |
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Stupid search button... |
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Quoted: Although currently banned from the arfcom, Mos would like to respond that those antenna cables with SMA adapters I used on the flexible antenna can be bought on eBay, are well made and very inexpensive and come in different lengths...  Good to know and thank Mos for posting the picture. |
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Quoted:
Quoted:
You can make one from the coax itself, and you don't need a ground plane. I've made one and it works fine. coax bazooka I kind of chuckle sometimes about all the enthusiasm for the roll up j poles and such, when this has similar performance and is much easier to make. If you have ferrites handy there is an even easier way to make that, just use the ferrites to terminate the "dipole" instead of trying to fold the braid back. Can also move them up and down on the coax to fine tune the resonance. Yep I used a choke because I was lazy 
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I am working on something similar to that, but uses a "Tiger Tail" at the SMA connector for a ground plane. i plan on putting it in a Molle platform for attaching at the back of the vest and running the coax up the back of the vest and the antenna above the shoulder.
It will be fun to test, many of us want to keep the radio low so rifle transitions are not inhibited, but you run into coupling with the body. If the design works it will be very similar to a vertical half wave dipole. |
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Quoted:
I am working on something similar to that, but uses a "Tiger Tail" at the SMA connector for a ground plane. Just use a coax braid overwrap instead of the single wire, or a choke coil or ferrite beads like we were discussing for that vertical dipole antenna. If you do a braid overwrap you can put heat shrink over the whole thing. |