I'm looking at setting up a UHF vehicular repeater for my VHF 110 watt Astro Spectra with Siren/PA. I have a regular SP02 Expo VRS but, I'm told it will not work because the VRS-EP is meant to interface to these Astro's.
So is there a way I can swap out the Firmware on my VRS to make it a VRS-EP? If not what are some other 3rd party products that will interface with an Astro Spectra, like Pyramid or FutureCom? Also could anyone chime in on how succesful these 3rd party products have served their needs.
P.S. This setup will be used on conventional frequencies.
Thanks in advance.
Astro Spectra Vehicular repeater
Moderator: Queue Moderator
You can confirm this yourself by getting the Motorola manual 6807993D96: Astro Spectra Vehicle Repeater System - Expanded Protocol.
The VRS-EP is a different animal that does not use the original VRS circuit board, therefor you cannot exchange a VRS-EP processor chip with a VRS processor chip (the processor chip is where the VRS firmware lives). If your SP02 is a BASP02 or BWSP02 model you should be able to swap the R-NET crystaled radios between the VRS-EP and your VRS (it could save you recyrstaling cost). You should also be able to use the current model VRS-750 with the Astro Spectra.
The VRS-EP is a different animal that does not use the original VRS circuit board, therefor you cannot exchange a VRS-EP processor chip with a VRS processor chip (the processor chip is where the VRS firmware lives). If your SP02 is a BASP02 or BWSP02 model you should be able to swap the R-NET crystaled radios between the VRS-EP and your VRS (it could save you recyrstaling cost). You should also be able to use the current model VRS-750 with the Astro Spectra.
If they are both the same frequency split the Expo and R-Net RF boards are the same (maybe small differences for manufacturing revisions like an A rev. vs a B rev., etc.). The audio support boards and connections are different. You can use either manual to get the frequency formula. I have never tried it, but in theory you could pull the radios apart and exchange the Expo RF board with the R-Net RF board which would be a extreme (but cheap) way to change the crystals. In your case if you are very careful you could just unsolder and swap the crystals if the RF boards are from the exact same split. You would have to do a complete alignment in any case.
These radios have one quirk. There is the usual Rx crystal, Tx crystal and an additional Rx mixer crystal for the 455 KHz second IF. The extra crystal frequency is set to high side or low side 455 KHz injection. I do not see why Motorola didn't just pick one frequency and leave it alone, but instead Motorola has a table that uses one of two different crystals (high or low side injection) depending on the Rx frequency. If you follow the Motorola plan, when you recrystal one of these radios you may end up needing 3 crystals (2 per each channel and a single additional IF crystal) depending on what the table said and which second IF crystal you already have. These crystals are radio type specific harmonic cuts (for the main Rx and Tx) and temperature balanced (compensated) with the oscillator circuit characteristics, so junk box crystals or any old common unspecified crystal types are not good enough if you want to get on and stay on frequency. I'm not sure about crystal availability from Motorola, however in the old days you could just call one of the big crystal manufactures and they kept complete records of what type of crystals and frequency formulas different commercial radios needed. You would just give them your frequencies, radio model and they would do the rest. I cannot imagine that they would throw away all this information, so you could still probably do it this way as well.
These radios have one quirk. There is the usual Rx crystal, Tx crystal and an additional Rx mixer crystal for the 455 KHz second IF. The extra crystal frequency is set to high side or low side 455 KHz injection. I do not see why Motorola didn't just pick one frequency and leave it alone, but instead Motorola has a table that uses one of two different crystals (high or low side injection) depending on the Rx frequency. If you follow the Motorola plan, when you recrystal one of these radios you may end up needing 3 crystals (2 per each channel and a single additional IF crystal) depending on what the table said and which second IF crystal you already have. These crystals are radio type specific harmonic cuts (for the main Rx and Tx) and temperature balanced (compensated) with the oscillator circuit characteristics, so junk box crystals or any old common unspecified crystal types are not good enough if you want to get on and stay on frequency. I'm not sure about crystal availability from Motorola, however in the old days you could just call one of the big crystal manufactures and they kept complete records of what type of crystals and frequency formulas different commercial radios needed. You would just give them your frequencies, radio model and they would do the rest. I cannot imagine that they would throw away all this information, so you could still probably do it this way as well.
I ordered crystals for the Expo back in December but, never got a chance to put them in. The freq is 462.xxx TX and RX. I went through International Crystal and they said nothing about a 3rd crystal, nor did I ask them about it, I guess I should have now. What is the bandsplit for UHF Expo and Rnet VRS's? Because, the VRS I may be getting is from TVA and that is govenment stuff. Thanks again
Stu
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twowaytekk
- Posts: 219
- Joined: Sat Feb 23, 2002 4:00 pm
Repeater
If you are only needing a UHF repeater with 25KHZ spacing I'd just geta used UHF Pyramid repeater and hook it into the Spectra. The Pyramid repeaters can be found on Ebay and are usually less than $100. All the technical manuals and their software can be found on their website. Not to mention they can be programmed by a Vertex programming cable.
You can then use the VIP settings on the control head to turn the repeater on/off.
Mark
You can then use the VIP settings on the control head to turn the repeater on/off.
Mark