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Transmitter antenna help
Bert Hyman wrote:
You appear to be posting from the US, so I thought I'd mention that if this transmitter is an unlicensed "Part 15 Intentional Radiator" This is a legal device. You can find them at Comtek (www.comtek.com). I'm just trying to replace the antenna system they are using, which is a lapel mic with about 48" of shielded cable between the 1/2" connector and the mic head, with a fixed, shorter high-gain (rubber ducky type) antenna. Can anyone help me to accomplish this? What do I need in terms of the antenna... the exact type? Thanks. |
#2
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Transmitter antenna help
"scooterspal" wrote in message ... Bert Hyman wrote: You appear to be posting from the US, so I thought I'd mention that if this transmitter is an unlicensed "Part 15 Intentional Radiator" This is a legal device. You can find them at Comtek (www.comtek.com). I'm just trying to replace the antenna system they are using, which is a lapel mic with about 48" of shielded cable between the 1/2" connector and the mic head, with a fixed, shorter high-gain (rubber ducky type) antenna. Can anyone help me to accomplish this? What do I need in terms of the antenna... the exact type? Thanks. 'high-gain rubber ducky' isn't that an oxymoron?? rubber ducks are usually much lossier than full size antennas. |
#3
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Transmitter antenna help
scooterspal wrote:
Bert Hyman wrote: You appear to be posting from the US, so I thought I'd mention that if this transmitter is an unlicensed "Part 15 Intentional Radiator" I'm confused, now. Their web site (www.comtek.com) shows the newer models operate in the 216-217Mhz band. I have a frequency counter. Is there a way I can make a wire loop and set the trasmitter near it to pick off the operating frequency? Thanks. |
#4
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Transmitter antenna help
"scooterspal" wrote in message ... scooterspal wrote: Bert Hyman wrote: You appear to be posting from the US, so I thought I'd mention that if this transmitter is an unlicensed "Part 15 Intentional Radiator" I'm confused, now. Their web site (www.comtek.com) shows the newer models operate in the 216-217Mhz band. I have a frequency counter. Is there a way I can make a wire loop and set the trasmitter near it to pick off the operating frequency? Thanks. yes, make a wire loop, put the transmitter near it and read the frequency... just like you said. |
#5
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Transmitter antenna help
(scooterspal) wrote in
: Bert Hyman wrote: You appear to be posting from the US, so I thought I'd mention that if this transmitter is an unlicensed "Part 15 Intentional Radiator" This is a legal device. You can find them at Comtek (www.comtek.com). I didn't say illegal, I said unlicensed. -- Bert Hyman | St. Paul, MN | |
#6
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Transmitter antenna help
OK. I have tested the frequency and found it to be 75.489Mhz. Should
have done this first, sorry for the confusion. Comtek did make systems that operated betweeh 72 and 76Mhz. This is one of those. That said, where do I stand antenna wise? Thanks! |
#7
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Transmitter antenna help
On May 30, 12:50 pm, scooterspal wrote:
OK. I have tested the frequency and found it to be 75.489Mhz. Should have done this first, sorry for the confusion. Comtek did make systems that operated betweeh 72 and 76Mhz. This is one of those. That said, where do I stand antenna wise? Thanks! Depending on how large a distance you want it to cover, you may get by with a considerably shorter antenna than the 48 inch recommended size. But you also didn't say, that I could see, that there was a problem using a 48" piece of wire. Obviously it's not too critical since in use the mic cable can be bent in all sorts of different shapes and it still operates. In other words, try to not make this more difficult than it needs to be. If you need the mechanical antenna to be shorter than 48 inches, just wind that length of wire in a spiral, spaced out as much as you can accommodate. Try that and see how it works. Easy enough? If you need higher performance, that's possible, but in general very short antennas won't be as efficient as straight antennas long enough to be self-resonant at the operating frequency. If you need good performance from a short antenna, get a system that operates at a higher frequency. Cheers, Tom |
#8
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Transmitter antenna help
K7ITM wrote:
If you need the mechanical antenna to be shorter than 48 inches, just wind that length of wire in a spiral, spaced out as much as you can accommodate. Try that and see how it works. Easy enough? If you need higher performance, that's possible, but in general very short antennas won't be as efficient as straight antennas long enough to be self-resonant at the operating frequency... Is that all a rubber ducky antenna is? 48" of wire wound around a flexible core of some type? If so, what do I look for (type, model, etc.) if I want to purchase one to try out? |
#9
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Transmitter antenna help
Is that all a rubber ducky antenna is? 48" of wire wound around a flexible core of some type? No, that isn't all that a 'rubber duck' antenna is, wish it were that simple. Since the question was asked, I have to assume that you aren't exactly familiar with what a transmitter 'looks' for in an antenna, or how that 'looked for' thing is arrived at. (And if you aren't sort of 'involved' in radio stuff, why should you be?) Once you learn about all that stuff it really isn't all that hard to figure. But that 'learning' can certainly be a real chore! - 'Doc |
#10
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Transmitter antenna help
....Rats, that didn't post like I thought it would. (Not enough
coffee.) Disregard the part with the "" thingys. Sorry 'bout that. - 'Doc |
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