Quantar Base to CEB link
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BJMCDANIEL
- Posts: 13
- Joined: Sat Mar 02, 2002 4:00 pm
Quantar Base to CEB link
We presently have a VHF Quantar Base with 3 additional Astro-Tac Receivers at a remote site approximately one mile from the dispatch point/CEB. This is analog, and is used for the Statewide interoperability channels, and Volunteer Fire Dispatching. Each receiver comes back to the CEB on a dedicated "dry pair" phone circuit. The fourth pair handles the Quantar receiver, and channel select for the transmit (4 receive channels, 3 transmit). We have used phone lines for this application for over 25 years. However, in addition to occasional "Backhoe fade", the line levels have become unstable, and we lose the transmit function. We have no redundancy. Thanks to deregulation, I don't see the phone company making wholesale improvements. I have been involved in applications where the VHF base would be hardwired back-to-back with a UHF radio, and I am inclined to do this here. I don't have the funds to do microwave. We are paying over $1K/mo for leased lines, and I feel like I can justify an alternative to leased lines. I have looked at some of the MDS stuff, but the application always seems to be for digital. I really don't wish to "kluge". Anybody been there, done that?
Sgt. B. John McDaniel, KE5PL
Midland County (TX) Sheriff's Office
GROL PG-10-15392
432-688-4613
Where am I now? http://www.findu.com/cgi-bin/find.cgi?KE5PL-10
Midland County (TX) Sheriff's Office
GROL PG-10-15392
432-688-4613
Where am I now? http://www.findu.com/cgi-bin/find.cgi?KE5PL-10
Others may differ, but my (limited) experience, and the concensus of some folks whose opinions I value, is that RF links when used to backhaul satellite receivers are simply not clean enough; the voter gets confused.
The other problem is that, unless the RF receiver link is keyed continuously, you will (a) suffer the composite receiver-link xmitter-link receiver attack time delay and (b) have to arrange somehow to have any signalling impressed on the link audio.
I am told that in most regions, one can upgrade "dry pair" phone lines to "FDDA" lines, which are self-supervising and tend to reduce balance and equalization problems. Of course, this will do nothing for your budget problems.
The other problem is that, unless the RF receiver link is keyed continuously, you will (a) suffer the composite receiver-link xmitter-link receiver attack time delay and (b) have to arrange somehow to have any signalling impressed on the link audio.
I am told that in most regions, one can upgrade "dry pair" phone lines to "FDDA" lines, which are self-supervising and tend to reduce balance and equalization problems. Of course, this will do nothing for your budget problems.
As I read your post I concluded that your Quantar and receivers are all at a single remote site and collectively comprise what we call a T4-4R station. This is a hardware configuration that can appear at the control point as if it is four separate base stations with the exception that you can only transmit on one frequency at a time.
The advantage over a single radio is that you can always hear any transmission directed to you on any of the four channels regardless of traffic on any of the other channels.
If this is the case, you could remote control this configuration over radio without encountering RKG's [very real] concerns which apply to voting systems. In the way-back-when Motorola used to sell an HT based RF link product for just this purpose. Perhaps there is still something similar available.
The uplink [control point to Quantar] path will need to be relay keyed and the remote control device [e.g. console] should have extended high level guard tone.
The advantage over a single radio is that you can always hear any transmission directed to you on any of the four channels regardless of traffic on any of the other channels.
If this is the case, you could remote control this configuration over radio without encountering RKG's [very real] concerns which apply to voting systems. In the way-back-when Motorola used to sell an HT based RF link product for just this purpose. Perhaps there is still something similar available.
The uplink [control point to Quantar] path will need to be relay keyed and the remote control device [e.g. console] should have extended high level guard tone.