Spectra -> Astro Spectra transplant

[BIODTL1997]

I would post this over at batboards, but they are in the process of migrating to a new system, apparently.

Does anyone know if it would be possible to transplant the RF sections of a spectra into an astro, or vice versa? (utilizing the brains of the Astro, but the arms and legs of the Spectra. There seem to be plenty of 800M astros out there, but I need a UHF radio, with P25 functionality. Can these 2 radios have a love child?

Thanks!

 

[Tech792]

No...you can't mix and match heads and chassis. Only the control cable is the same...Radios are totally different even though they look the same.

 

[radioman2001]

Not true, you can take the entire RF assembly, front end, receiver, vco and swap them out into an Astro Spectra then the Astro command board would have to be band changed to from whatever you have to what you want. You will also have to use the Astro heads, since they use a different processor in them. I was trying to do the same, but the radios I went to bid on went for WAY too much for what they were. I have a VHF, but it is hardly worth the work, since it only has a basic flash.

 

[motorola_otaku]

There seem to be plenty of 800M astros out there, but I need a UHF radio, with P25 functionality. Can these 2 radios have a love child?

Kinda sorta. If you want a UHF radio it's much easier to start with a UHF Range 1/Q-split (403-433 MHz) Astro so you'll have a UHF Astro RF board. You can move an 800 MHz RF board down to VHF with some SMT component work but without looking at the detailed service manual I can't tell you if 800 -> UHF is possible.

The components you will be taking from the analog Spectra are the PA deck, the VCO, and the RX preselector. The Astro radio provides the RF board, the command board, the VOCON, and the control head. Obviously the analog Spectra needs to work in your target band. Once you get the radio assembled you use MTSX Lab RSS to blow in a s-record from an Astro radio operating in your target range, then you perform a full service alignment. To get P25 capability the Astro VOCON needs to have P25-capable HOST and DSP firmware and the donor Astro s-record needs to have P25 enabled in the flash. And that's pretty much all there is to it.

 

[mancow]

And, the nice thing is the astro uhf receivers are broad band and will work across several ranges.

The cheapest combo is to get a low split astro and 450 analog. Do the appropriate swap of parts, hit it with a 430-470 range s rec, tune and you are done.

 

[BIODTL1997]

Wow, that's a lot of good info. Thanks.

What I'm attempting to do, in theory, is RSS-mod a 800 P25 command board into a UHF 4 split, and dropping it into a spectra chassis on that band. Sounds like a lot of work though, so I guess I'll just wait around for that UHF Astro to magically show up somewhere.

 

[mancow]

It's not much work at all as long as you have all the parts.

The vocon is what gets edited not the command. A command is frequency independent and is just an interconnect. The vocon has to have the appropriate radio personality (band type, head type, etc...) loaded. You will need an astro uhf receiver board for the uhf analog body but you can reuse the amp, preselector and vco if they are the same split you are wanting to stay with.

 

[gary123]

to sum up all the posts

the rf sections are interchangable but the logic and interface componants are not.

 

[BIODTL1997]

Great, I got it. Thanks guys!