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Listening to myself talk on repeaters
Sometimes I have a good enough signal to a repeater that I can key in,
but not enough to have anything other than a carrier signal get through. Now, if I'm trying to get attention on a repeater on, say, the 2 meter band, how do I know whether I'm full quieting and there is just no one listening at the moment or I'm having problems getting through? A friend suggested having a scanner handy with earphones to listen to myself on the output freq. I tried that and it didn't seem to work at all. I'm using a Kenwood TH-F6 to transmit on 2 meters and I have an Icom R3 tuned to the output of the repeater I am keying up. I don't have any problems getting into the repeater and everyone seems to hear me just fine. The only thing is, I can't hear myself through the Icom when I transmit on the Kenwood. The Icom is functioning otherwise. It picks up the output of the repeater without issue unless I am transmitting through it with my TH-F6. For a moment I thought that my hearing was to blame, so I dug out an old analog oscilloscope that I had bought at a MIT flea market years ago for about $75. I visually watched the audio output of the Icom with the scope. When other operators were transmitting through the repeater I could see their voices dance on the blue-green glowing screen of the scope, but when I transmitted all I saw was a flat-line. Why is my scanner deaf when I'm transmitting with a separate rig? Could this have anything to do with near-field emissions? I'm transmitting with 5 watts of power using a 7.5dB gain omni-directional antenna. My scanner is always within 10 feet of the antenna. Repeater output freq: 147.000 MHz Offset: -600KHz BTW, I've talked with another ham that has experienced the same thing, so at least I know I'm not going nuts just yet. :) KC2MAC |
Front end overload.
It's like trying to see a candle next to a spotlight shining in your face. |
Radioman wrote in message ...
Front end overload. It's like trying to see a candle next to a spotlight shining in your face. Even though they are different freqs? I'm transmitting on 146.400, but listening on 147.00 (-600k offset). Is there anything I could do to treat the symptom aside from keeping the antennas of the two units far apart from each other? I wish I had a spectrum analyzer. I'd love to see definitively what is happening to the spectrum when I transmit. Maybe there is a way I can turn my old oscilloscope into a spectrum analyzer. hmmmmmmm... KC2MAC |
On 2 Dec 2003 09:32:01 -0800, (KC2MAC) wrote:
Radioman wrote in message ... Front end overload. It's like trying to see a candle next to a spotlight shining in your face. Even though they are different freqs? I'm transmitting on 146.400, but listening on 147.00 (-600k offset). You may think it's a lot, but 600 kHz to an FM radio can be quite close. Is there anything I could do to treat the symptom aside from keeping the antennas of the two units far apart from each other? See my other response regarding antenna polarization and duplexers. You could actually build a simple notch filter out of a piece of coax and a T fitting. It's not going to be very deep, and it will be wider (in terms of bandwidth) than a duplexer, but every dB helps in this case. I wish I had a spectrum analyzer. I'd love to see definitively what is happening to the spectrum when I transmit. Look at any transmitter product review in QST, especially HF gear. Basically what you will see is a very high spike at the transmit frequency, with progressively diminishing sidebands for several hundred Hz either side of the carrier frequency. There will also be some highly attenuated spikes at periodic intervals above and below the carrier frequency. Maybe there is a way I can turn my old oscilloscope into a spectrum analyzer. hmmmmmmm... Probably not. LRod Master Woodbutcher and seasoned termite Shamelessly whoring my website since 1999 http://www.woodbutcher.net |
Hey - Merry x-mass Rod...
from the cold in Naperville.... Wes "LRod" wrote in message ... On 2 Dec 2003 09:32:01 -0800, (KC2MAC) wrote: Radioman wrote in message ... Front end overload. It's like trying to see a candle next to a spotlight shining in your face. Even though they are different freqs? I'm transmitting on 146.400, but listening on 147.00 (-600k offset). You may think it's a lot, but 600 kHz to an FM radio can be quite close. Is there anything I could do to treat the symptom aside from keeping the antennas of the two units far apart from each other? See my other response regarding antenna polarization and duplexers. You could actually build a simple notch filter out of a piece of coax and a T fitting. It's not going to be very deep, and it will be wider (in terms of bandwidth) than a duplexer, but every dB helps in this case. I wish I had a spectrum analyzer. I'd love to see definitively what is happening to the spectrum when I transmit. Look at any transmitter product review in QST, especially HF gear. Basically what you will see is a very high spike at the transmit frequency, with progressively diminishing sidebands for several hundred Hz either side of the carrier frequency. There will also be some highly attenuated spikes at periodic intervals above and below the carrier frequency. Maybe there is a way I can turn my old oscilloscope into a spectrum analyzer. hmmmmmmm... Probably not. LRod Master Woodbutcher and seasoned termite Shamelessly whoring my website since 1999 http://www.woodbutcher.net |
On Thu, 25 Dec 2003 16:50:59 GMT, "TheTenor"
wrote: Hey - Merry x-mass Rod... from the cold in Naperville.... Wes Holy ****, aren't I safe anywhere? How're things? LRod Master Woodbutcher and seasoned termite Shamelessly whoring my website since 1999 http://www.woodbutcher.net |
Well, using the moniker "LRod" is kinda like flashin' your headlights at me
as we pass in the dark g. Nah - you're safe enough... Hey I installed an FT817 in my Honda Accord and one of these days I'm gonna buy a mobile antenna so I can play hf and 6m on it. So far I'm only on 2m and 70cm. My son, Tom, actually dug out his old handi-talkie and we had a short qso on what used to be AFAR uhf. Trying like hell to play a bit more. This running my own business has kept my plenty busy... Anyway, enough of this conversation on a public forum. Just had to at least say "hi"... Ever get back up this way? If ya do, look me up. Actually I may be in Miami Lakes this March. My big client reps a hotel/golf resort there and his winter meeting is at the hotel. Don't remember where you are but thing you are further north... Wes "LRod" wrote in message ... On Thu, 25 Dec 2003 16:50:59 GMT, "TheTenor" wrote: Hey - Merry x-mass Rod... from the cold in Naperville.... Wes Holy ****, aren't I safe anywhere? How're things? LRod Master Woodbutcher and seasoned termite Shamelessly whoring my website since 1999 http://www.woodbutcher.net |
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