Batboard

Hi all,

Looking for a solution to my problem, any thoughts on this would be welcome

Have a customer that has a 4 site voting system, with two sites being repeaters set as base stations. Using a JPS SNV comparator.
Currently, the main transmit site is set for in cabinet fall back for stand alone repeater operation. All links are through microwave, except one RX site that is rtna. All equipment are quantars and astro tac RX'rs. Both repeaters have SAM cards.

Here is what I would like to do.

Retain same set up with in cabinet fall back repeater on the main TX site, which will alllow for single site coverage in case of micrwave failure.

What I would like to is at the secondary TX site be able to remotely (maybe over air) shut down the main TX site and wake up the repeater at the second site.

My fear is a microwave failure to the main site and/or a failure of equipment at the main tx site. Want the dispatcher over the air to be able to set-up/knock down repeaters. The dispatcher has the ability at the console to switch between microwave and a CDM remote base incase of micro failure.

- Rob

This is easy, I've done it.

Have the TX wireline key both stations on F1 for normal ops.

Program F1 in Quantar 1 to have the correct TX frequency, program F1 in Quantar 2 to have 0.0MHz as the TX frequency.

Program F2 in Quantar 1 to have 0.0MHz as the TX Frequency, program F2 in Quantar 2 to have the correct TX frequency.

Set the console up to instruct the voter to allow keying on F1 or F2.

When you key on F1 (1950Hz) you'll get Site 1.

When you key on F2 (1850Hz) you'll get Site 2.

Might take some tricky programming in the SNV-12 to get the tones to stick, but the dispatcher should be able to make use of this Main/Standby mode by just changing channels.

Now that doesn't fix your microwave path loss issue.

The SAM can be programmed to allow DTMF setup/knockdown which in turn can be programmed into autodial phone slots on your CDM remote base or set up as DTMF paging codes on your dispatch console.

You set the same codes in both stations, only reverse them. The setup code for repeater 1 is the knockdown code for repeater 2, and vice-versa. This way there can never be more than 1 station on the air.

You can also use the SAM for channel control and "steer" the active repeater over the air using DTMF much like I described with the wireline channel select above. Same programming scheme, just use the channel select features to set one up and simultaneously knock the other down. You'll need to make sure your wireline situation doesn't steer the station back to the wrong place if you decide to do this, though.

Third option is spend some more money and make the thing simulcast.

Hope some of this helps.

I like that plan. Should work just fine if the SAM works as advertised. It will probably take some experimentation to ensure all goes as desired. I have a Quantar wildcard script for multi-site systems that forces one of the stations to in-cabinet repeat if the microwave link fails. The danger of it is the possibility of two transmitters up at once.

I've done this in the past with any sort of external DTMF decoder wired onto the backplane of the Quantars... (I believe its connector J17) Just pick off the discriminator audio and feed it into the decoder.

The decoder I used (which i can't recall at this point!) had N/O and N/C contacts. I figured out which pin was "RPT KNOCKDOWN" and simply set up the primary repeater to be connected to the "N/O" contact set -- and connect the "N/C" contact set gets wired into the "secondary" repeater. (Tie the common to ground). Program both decoders for the SAME CODES! IE:

#1111* = Switch to main
#2222* = Switch to secondary

Since they're both programmed to respond identically to both commands, there's no way for the system to get 'hung up' -- simply re-send the mode you want to enable. DTMF is easily added to most paging consoles. Added benefit is that you can activate the system anywhere within the coverage range of (both) recievers.

Sorry if i'm not being super clear about this! PS: You could also have it force a channel switch, and use those parameters to change the repeater operation, instead of just simply knocking down the repeater. I think you'll need the knockdown due to the in-cabinet repeat, though.

While it's a good idea, it's reinventing the wheel. The OP has SAM cards in the stations, and programming the SAM cards for what he wants them to do is detailed in the Quantar manual.