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Posted: 3/7/2013 5:17:14 PM EDT
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I have gotten my tech license &
a Wouxan. I have seen here that a short coax cable is used to remote mount the antenna away from the HT, I suppose. Can someone explain how that works? Pics maybe? Thanks! John |
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Simple thing to do IF your radio uses RF connectors at the antenna base and the antenna can be unscrewed.
Here are two photographs of a simple way to do it. In the example, the radio uses SMA connectors for the antenna. You need to insert a cable between the radio and antenna, in this case one with a male SMA on one end and female at the other. Then route the cable to the remote antenna location, say at the top of the chest rig strap. Radio is at one end of the cable, and the antenna is at the other end. http://i1308.photobucket.com/albums/s602/toucan67/RadioWCable_zpsd8c9d768.jpg http://i1308.photobucket.com/albums/s602/toucan67/RadioCnctd_zps969fc947.jpg It would be wiser to use a balanced antenna on the end of the cable: One with a ground element AND a radiating element. Like a dipole or a patch antenna or such types. Or were you asking something else? |
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This is what I was asking about.
I wanted to claify how the pro's run comms on their rigs. My radio has an SMA out, but I would like to run it with an SMA to BNC converter, which I have. I want to run everything BNC because it quicker & easier. I have noticed that some of the coax extensions that I have seen here have has one 90 degree connector. What is that for? Or is it required? Would the antenna be ran vertically up a shoulder strap? Across the grab handle? General set up on the kit, is what I want clarifed. Thanks! John |
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I agree that remoting to a small whip might not be worth the effort. It is important that the antennas at both radios share the same polarity: Both horizontal or both vertical, and when you remote a simple whip and that procedure, if it turns the antenna on its side so it is now disposed horizontally instead of vertically, then there are losses from THAT fact as well.
This is why I mentioned patch antennas and others. I wouldn't bother running a remote antenna for close range comms for two reasons: The most important reason is that the antenna connectors on consumer grade radios are NOT mounted in particularly robust housings. It is pretty easy to break the radio case where the connector is mounted. When you attach a cable there it becomes easier to apply enough force on the cable to break things. If you add a coax adapter (say, SMA to BNC) you have introduced a heavy, stiff lever on that connector. If you fail to protect that VERY well, you are likely to break the antenna connector off the radio. It is cheaper to buy a higher powered radio in the first place to overcome the range problem, than it is to replace a less powerful radio over and over because you are breaking them. The military antenna extension cables I have seen are VERY flexible, VERY strong, and VERY expensive cables, such as made by W.L. Gore, that overcome some of the strain problems. These top quality cables can be found on eBay, and every one of the type I have ever purchased was A-OK for our purposes, but they might have "poor" performance in lab instrument settings in ways that don't affect us a whit. Antennas in use by spec ops are a subject I have no knowledge of. If I were making something for remote antenna-on-the chest rig, I would keep it simple and use a 5/8 wavelength (or equivalent helical whip) because those are very much less subject to typical ground plane requirements (counterpoise) than some of the other antennas, and they should be cheap and easy to find. |
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BTW, one reason that remote antennas are used with radios carried at belt or chest level s that some of the radios operate at high frequencies such as 2.4gHz and operate at very low transmit power levels. In the case of digitally modulated radios at those frequencies, the absorption by the body can make the difference between having comms and not having comms.
The antenna would have to be elevated to overcome those losses if operated at a low power. For purposes of limiting detection range, these are very low power radios. Like all digital signals, you either have a signal, or you have none - no such thing as a scratchy signal. Not such a big deal at VHF and UHF at close range. |
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What are these cables called on Gores website? I can't seem to find them. Do they come in different lengths?
Thinking of maybe putting antenna through molle on back of vest and running a cable like this to the front to make it easier to use with out having to pull the antenna out of the molle to use the radio and then struggle to get in threaded back through the molle when I'm done. I have a Yaesu VX-8DR with a Diamond SRH320A antenna just for the record. |
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I chose words poorly.
Reminiscent of Gore coax would have been more accurate. I cannot provide an MX or NSN number for any of the military cables, because I know none of them. What I saw is cable that had the general construction of the following picture. The coax in the picture is a (damaged) cable that LOOKS much like the one in my earlier linked antenna extension patch cords, however the coax underlying the outer jacket is MUCH more flexible. The coax is within a tough outer jacket shrunk over a helical stainless wire, and this outer protection is free-floating so flex of the cable is unimpeded. Likely, any similar cables you see for sale will have the same general characteristics. This one has N connectors on it, and I bet that is what you find more often than not. N connectors are way too large for this kind of use even with adapters, and as I mentioned the adapter/connector chain leaves you vulnerable to breakage anyway. So I suggest that you select the cable for the correct connector at the radio end and adapt if necessary at the antenna end only. http://i1308.photobucket.com/albums/s602/toucan67/Peltor/Coax_zps66eee05d.jpg |
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Take a look at this.
Is this kinda sort of what you're talking about? I've been pondering the same question about comms and antennas as you. I haven't made up my mind if I want to go the el cheapo chi-com radio route or the old motorola xts route yet. |
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wileyz, That is the patch antenna design I was referring to in my posts.
I have used right angle connectors in portable equipment, and I found them to introduce a real risk for catching on things and causing equipment damage. There may be some reason the operators asked for that feature, but I doubt it, since the U229 audio connector already sticks up right next to the antenna cable (and is much larger and longer) and bending the antenna coax to the desired shoulder is no big deal. |
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You can get it with a straight connector standard or the 90 degree one by request. The 90 degree one is for dudes that like running the wire through the channels on the cummerbund of their plate carrier to their back. Running the cable up the front of the PC is a NO GO because the radio pouch is mounted to the cummerbund and that would interfere with donning/doffing the PC especially in an emergency.
That and the antenna no workie real good when sammiched betwixed the ground a smelly bearded dude. I get what your saying about the connectors on commercial radios being on the cheesy side. Been there, Broke a bunch of them. 
I just want to know if that antenna will work well with a civilian VHF/UHF radio and how many kidneys I'll have to harvest to buy one if it is worth it. |
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Quoted:
BTW, one reason that remote antennas are used with radios carried at belt or chest level s that some of the radios operate at high frequencies such as 2.4gHz and operate at very low transmit power levels. In the case of digitally modulated radios at those frequencies, the absorption by the body can make the difference between having comms and not having comms. The antenna would have to be elevated to overcome those losses if operated at a low power. For purposes of limiting detection range, these are very low power radios. Like all digital signals, you either have a signal, or you have none - no such thing as a scratchy signal. Not such a big deal at VHF and UHF at close range. That's not why you remote body-worn antennas. Body-worn antennas are remoted for two reasons - so the radio can be put in a position where it is safer, and the antenna is still useful, and so an rf switch can be installed for use with dual antennas. If you don't remote the antenna, you'll have the antenna hitting you in the face, poking you in the eye, etc. it allows you to move it to a better spot on your plate carrier (some wear it on their back, some across the front), where it can be tied down and stay out of the way, also allows the radio to be pulled out and stored or charged without having to untie the antenna from body armor. I always used a remote battery cable with a 5590 battery, a standard whip multiband antenna, an rf switch, and a DMC-125 on the off chance I absolutely had to talk to a satellite. Afghanistan is a big country and LOS comms are not useful everywhere. |
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Quoted:
Take a look at this. Is this kinda sort of what you're talking about? I've been pondering the same question about comms and antennas as you. I haven't made up my mind if I want to go the el cheapo chi-com radio route or the old motorola xts route yet. That patch isn't going to work for shit. |
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I don't suggest any super wideband antenna for OUR use. We use single channel analog FM radios on VHF or UHF or 800mHz, not frequency hopping gear designed to interoperate anywhere.
No need to get an antenna of the patch type or otherwise that gives up efficiency the band we are using in favor of mediocre performance on all bands. If you want a patch or whip antenna for any particular band, say for FRS or the 2m ham band, get one optimized for the band you use. |
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