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CB repeater
- Thread starter towerdog
- Start date
Actually, when you think about the required frequency separation, there isn't any appreciable difference between saying 'off-set' and 'cross-channel'. They both are going to be about the same for the frequency and mode of use. Assuming you mean adjacent channels.
I have a problem with why anyone would even want to use a repeater on a band where it isn't really going to do much practical good (if any). A repeater is used to extend the range of VHF/UHF bands beyond what is normal. Is there really any practical point in extending the 'normal' range of an HF band that in effect doesn't have limits, other than "Momma Nature"? So, other than because it's possible, why would you want to do it?
- 'Doc
I have a problem with why anyone would even want to use a repeater on a band where it isn't really going to do much practical good (if any). A repeater is used to extend the range of VHF/UHF bands beyond what is normal. Is there really any practical point in extending the 'normal' range of an HF band that in effect doesn't have limits, other than "Momma Nature"? So, other than because it's possible, why would you want to do it?
- 'Doc
To give us something annoying to listen to when the band is open.
BEEE-BOOOOP! BEEE-BOOOP! all day long from the damned "courtesy" tone. :headbang That machine on 29.640 in the Virgin Islands would drive me crazy as it had no PL tone on the input. Any little burst of static would set it off.
Good example of a 10 meter repeater use. You and the station you are talking to both have propagation to the repeater location but cannot talk directly due to not having propagation between each other's location.
RCB
Back in the 1980's one of my locals took a TRC-422 and a Regency VHF marine radio and built a CB repeater out of them. He built them into a weatherproof box and planted it on top of one of the tallest water towers in town. It was powered by a deep cycle battery and solar panel. The device was only simplex one way. You would transmit on an unused VHF marine telephone channel (no one on VHF could hear you because the phone channels are duplex) and it would come out on channel 21 CB. You would listen on your CB. The thing had great range and ran for many years before it finally crapped out.
Until the late 1990's you could drive by with binoculars and still spot the steel whip with a vise grip mount on top of the tower. Now it's been all replaced with cell phone panels. I wonder what the cell phone people thought when they found the old repeater up there? The builder told me he put one MRF-492 after the CB and it gave a 25 watt carrier with 100 watts PEP. As high as it was it out talked many bases in the area.
At one point he told so many people what VHF channel was it's input that people would talk the battery dead. A day of sunlight brought the system back up again. It used a Radio Shack 2 meter 5/8 wave magnet mount as the receive antenna. I asked about how he wired the radios together. It was nothing more then a relay operating off the squelch of the VHF radio to key the CB. The quality audio was the result of using the 10 watt audio amp in the VHF radio to directly modulate the audio transformer of the TRC-422.
The frequency split between CB and VHF high band was great enough to eliminate any interference even with the antennas about 20 feet apart. You had to remember to keep the VHF mic away from the CB speaker or it would feedback. Some people used it to mimick the Browning ping. As I reacall you could reach it's input from about 20 miles away and the CB output reached over 70 miles in some directions.
Until the late 1990's you could drive by with binoculars and still spot the steel whip with a vise grip mount on top of the tower. Now it's been all replaced with cell phone panels. I wonder what the cell phone people thought when they found the old repeater up there? The builder told me he put one MRF-492 after the CB and it gave a 25 watt carrier with 100 watts PEP. As high as it was it out talked many bases in the area.
At one point he told so many people what VHF channel was it's input that people would talk the battery dead. A day of sunlight brought the system back up again. It used a Radio Shack 2 meter 5/8 wave magnet mount as the receive antenna. I asked about how he wired the radios together. It was nothing more then a relay operating off the squelch of the VHF radio to key the CB. The quality audio was the result of using the 10 watt audio amp in the VHF radio to directly modulate the audio transformer of the TRC-422.
The frequency split between CB and VHF high band was great enough to eliminate any interference even with the antennas about 20 feet apart. You had to remember to keep the VHF mic away from the CB speaker or it would feedback. Some people used it to mimick the Browning ping. As I reacall you could reach it's input from about 20 miles away and the CB output reached over 70 miles in some directions.
We run into old junk on towers all the time and think little of it. It is unfortunate most ham installations are so poorly done, I have found antenna setups consisting of rope and rotten wood attached to the tower with black tape before. Most tower climbers also have no clue what the stuff is or what it does, especially the guys who put up cellular. If it had been me, I would probaly changed the battery. lol
A crossband repeat on VHF marine, thats even more ill-egal than my idea of crossband GMRS/CB in a truck in the woods.
Well I just cannot think of any use I would have for a CB repeater other than to prove it can be done, and having an offset would be more of an unnecessary complication. I think one would have better luck repeating cross-channel, i.e. you talk on ch.2 and it spits it back out on ch.38, talk on 38 and spits it out on 2, kinda like crossband only within the band. Kind of a pain to use such, as everyone would need monitor ch.38 and when someone wanted to talk he need switch to 2 and then the other users could only hear you talk, but not hear each other on 38, so if someone else wanted to be repeated to the group he have to switch to ch.2 also, and then you could not hear him talk if you were on ch.2. It would not be bad for 2 users but for the love of puppies, I do not have the inclination to do such. I just want to learn and aggravate people in the process. I will complain about FCC violations the day the powers that be obey their own laws. Till then, if they arent hurting anybody, putting others in danger or delibrately jamming I could give a rats ass.
A crossband repeat on VHF marine, thats even more ill-egal than my idea of crossband GMRS/CB in a truck in the woods.
Well I just cannot think of any use I would have for a CB repeater other than to prove it can be done, and having an offset would be more of an unnecessary complication. I think one would have better luck repeating cross-channel, i.e. you talk on ch.2 and it spits it back out on ch.38, talk on 38 and spits it out on 2, kinda like crossband only within the band. Kind of a pain to use such, as everyone would need monitor ch.38 and when someone wanted to talk he need switch to 2 and then the other users could only hear you talk, but not hear each other on 38, so if someone else wanted to be repeated to the group he have to switch to ch.2 also, and then you could not hear him talk if you were on ch.2. It would not be bad for 2 users but for the love of puppies, I do not have the inclination to do such. I just want to learn and aggravate people in the process. I will complain about FCC violations the day the powers that be obey their own laws. Till then, if they arent hurting anybody, putting others in danger or delibrately jamming I could give a rats ass.
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