Wanted to run this by the experts on here to see if I can legally and technically get away with it.
Have a customer that has several VHF base station locations working off a regional MTR2000 tower site.. MTR has a pair of 151.xxxx and 159.xxxx. Bases are obviously programmed in reverse.
Customer is complaining of poor handheld coverage at some of the bases (duh, some of the bases are 20 miles from the tower). Looking for a low cost solution and customer has a bunch of existing channels licensed for moblie use as well as a couple of freqs listed as VR (even though they aren't using them).
Was considering converting one of the base stations into a CDM repeater using a RICK interface and another CDM. Obviously the "top" radio would be the talkback radio to the regional MTR. Bottom radio would be set to a licensed stand-alone mobile or VR freq and programmed for simplex. Handhelds that are not able to reach the repeater would then be programmed to match the simplex mobile/VR freq.. Obviously it would be nice if we could re-repeat the MTR2000 frequency, but that's not a possibility for obvious reasons.
And in case you're wondering, they only need handheld coverage in a very small area near the simplex radio in the CDM, so the "bottom" radio in the bi-directional repeater stack will be set for 5watts.
Feedback is welcome!
CDM in-band repeater/coverage question
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Ravenboy2001
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Re: CDM in-band repeater/coverage question
You are going to run into the legal aspect of the FCC if you just start to put up a
repeater without a license.
Anything can be done, it's just a question of how far you want to stick your neck
out. The FCC has been going after the radio shops as of late.
Is the customer even able to get another license for another repeater? If they can
get a license, then maybe a local low power repeater that kicks into the local base
remote to get to the central repeater. If it is legal, just remember about desense
and not messing up the receiver of the local control station they are currently using.
Jim
repeater without a license.
Anything can be done, it's just a question of how far you want to stick your neck
out. The FCC has been going after the radio shops as of late.
Is the customer even able to get another license for another repeater? If they can
get a license, then maybe a local low power repeater that kicks into the local base
remote to get to the central repeater. If it is legal, just remember about desense
and not messing up the receiver of the local control station they are currently using.
Jim
Ravenboy2001 wrote:Wanted to run this by the experts on here to see if I can legally and technically get away with it.
Have a customer that has several VHF base station locations working off a regional MTR2000 tower site.. MTR has a pair of 151.xxxx and 159.xxxx. Bases are obviously programmed in reverse.
Customer is complaining of poor handheld coverage at some of the bases (duh, some of the bases are 20 miles from the tower). Looking for a low cost solution and customer has a bunch of existing channels licensed for moblie use as well as a couple of freqs listed as VR (even though they aren't using them).
Was considering converting one of the base stations into a CDM repeater using a RICK interface and another CDM. Obviously the "top" radio would be the talkback radio to the regional MTR. Bottom radio would be set to a licensed stand-alone mobile or VR freq and programmed for simplex. Handhelds that are not able to reach the repeater would then be programmed to match the simplex mobile/VR freq.. Obviously it would be nice if we could re-repeat the MTR2000 frequency, but that's not a possibility for obvious reasons.
And in case you're wondering, they only need handheld coverage in a very small area near the simplex radio in the CDM, so the "bottom" radio in the bi-directional repeater stack will be set for 5watts.
Feedback is welcome!
Re: CDM in-band repeater/coverage question
It's a high band repeater talking to a high band repeater. Pretty straight forward. Just make sure the input freq is different than the output of the primary system, use a good quality duplexer, try to get at least a couple hundred K separation in all three freqs, and use a different PL.
Re: CDM in-band repeater/coverage question
We set up in band VR's all the time for a local S.O. They are on 154.xx RX/155.xx TX and the VR's are on 158.xx TX/RX. We use a notch filter (set to the VR's freq) on the mobile side, and a pass (set to the VR's freq) on the VR. The mobile uses a roof mount 3db ant, and the VR uses a 1/4 wave fender mount. 1.5 watts gives them about two to five miles coverage (they park their trucks and run off into the forest on 4 wheelers). Their is no reason that you can't have the mobile set as a semi duplex mode if the VR's freq is not within 2 or 3 megs of the input or out put if you are using two antennas with the correct filtering. What VR freqs do they have?
No as far a legalities, I'm not the best one to answer your question, but I would assume that you would need the "mobile" radio to me set up as a motile unit, not a base.
Check on Pyramid's web site, they have lots of info there. We use Pyramid's units, and their notch, and pass filters. The filters are all factory tuned and do a great job.
On a side note, not that this would apply to you but the units we install for the S.O. also need the mobile radio to operate up close to the VR's freq for other LEA's, so we use an antenna switch and a third antenna to bypass the notch filter. When the VR's get activated the relay kicks the notch filter in line.
Jim
No as far a legalities, I'm not the best one to answer your question, but I would assume that you would need the "mobile" radio to me set up as a motile unit, not a base.
Check on Pyramid's web site, they have lots of info there. We use Pyramid's units, and their notch, and pass filters. The filters are all factory tuned and do a great job.
On a side note, not that this would apply to you but the units we install for the S.O. also need the mobile radio to operate up close to the VR's freq for other LEA's, so we use an antenna switch and a third antenna to bypass the notch filter. When the VR's get activated the relay kicks the notch filter in line.
Jim