ctres
New Member
Posts: 955
|
Post by ctres on Jan 7, 2014 19:54:03 GMT -5
Quick question for you radio guys. Would a thales mbitr broadband antenna work on UHF freqencies such as gmrs and frs?
Edit: Found the answer, It's a yes for anyone interested.
|
|
|
|
Post by Zorak on Jan 7, 2014 21:27:02 GMT -5
It will also increase your radiated power. Using one on FRS-only frequencies will almost certainly put you way over FCC limits, so be careful how you use this.
|
|
ctres
New Member
Posts: 955
|
Post by ctres on Jan 7, 2014 22:28:50 GMT -5
Huh, this is news to me so thanks for cluing me in. Care to explain how that works or maybe you have a link to some good reading material on it? I'd love to find out more on this, I'm not particularly radio savvy but it's something I'd like to work on.
Edit: I've done a bit of searching and I may have come up with something close to an answer. Does this have to do with antenna gain? If I understand correctly a high gain antenna makes the transmitted signal more powerful but also more directional. Am I on the right track here?
|
|
|
|
Post by Zorak on Jan 7, 2014 23:48:12 GMT -5
Generally, assuming the same antenna type, a larger antenna means more radiated power. Pure FRS radios have strict limitations on radiated power. The GMRS and shared channels are more wide open.
|
|
ctres
New Member
Posts: 955
|
Post by ctres on Jan 8, 2014 8:37:29 GMT -5
Since FRS radios all have non removable antennas and are limited to .5W doesn't that make it technically illegal to operate most gmrs radios (icom, etc with removable antennas and 4-5W output) on pure FRS channels?
Do I understand correctly that pure gmrs channels do not have power limitations? I always assumed that any limitations were on the radios themselves, not radiated power, vut then again I did realize that there could be such a difference until now.
|
|
|
|
Post by X on Jan 8, 2014 8:43:45 GMT -5
|
|
ctres
New Member
Posts: 955
|
Post by ctres on Jan 8, 2014 9:19:40 GMT -5
So is the 5W limit on gmrs/frs shared channels a limit on the radio itself or a limit on the radiated power? Since radiated power seems like it would be hard to measure for the average user I would think that the restriction would be on the hardware itself hence the 5W rating that are typical for common GMRS radios or is this not the case?
|
|
|
|
Post by X on Jan 8, 2014 9:59:11 GMT -5
Radiated power, ERP. Although most radios transmit well below 5W so its hard to say if changing the antenna would result in going over the limit. You would need to find the current radiated power, the gain of the stock and aftermarket antenna and do some math.
Sent from my XT1080 using proboards
|
|
ctres
New Member
Posts: 955
|
Post by ctres on Jan 8, 2014 12:35:38 GMT -5
Okay thanks for the help guys, looks like I have a bit of research to do but I will probably go ahead with the antenna since I also have a smaller one to use besides.
|
|
|
|
Post by Zorak on Jan 8, 2014 22:34:04 GMT -5
Just use your head about it. Avoid using a huge whip antenna in a backyard game. If you pick up other people not playing airsoft on that frequency, change antennae or switch channels. As long as you aren't creating a problem, nobody will ever notice. It's not like the FCC has guys driving around looking for powerful GMRS signals.
|
|
ctres
New Member
Posts: 955
|
Post by ctres on Jan 8, 2014 22:39:40 GMT -5
Good advice, I'll be sure to follow it. I ended up scoring the antenna for $16 on ebay so I'll give it a try once I get my comms all sorted out. I going to try to get ahold of the specs on it to figure out exactly how much power I'll end up putting out.
|
|
