Batboard

As it is impossible for me to find a set of detailed and basic service manuals for the Spectra I cannot work out the resistor changes for the receiver section on the VHF radio. I want to add the pre-amp option to a few VHF units and I understand that it is less complicated than the UHF preamp (that I have successfully done).

Can someone point me to where I can pick up a set of manuals and/or the resistors and values that need to be changed on the receiver board?

I am kicking myself in the butt for being on vacation during the week when my former employer took all of the Motorola service manuals and tipped them into the dumpster.

PM or email me if you can provide helpful information.

thanks so much,

Fairly simple, just remove a few resistors and add two jumpers, and a resistor.

I will get the values that seem to work to you.

Are the Pre-amps the same in the Astro spectra as the regular spectra? I have a 50watt mobile with handheld control head that really would love to have a hotter receiver in it. My kenwood tk-7180 blows it out of the water.

kb9suy wrote:Are the Pre-amps the same in the Astro spectra as the regular spectra?

Yes they are the same or a later version, but the 'pre amp' section is the same. PIN diodes were added in the later frontends.

For a straight-up resistor change it sounds like they are just changing the gain. If I knew what it is and what it should be there would be some leeway in setting the stage amplification.

It has been mentioned, can someone post the resistor value changes for the VHF preamp?

Not having or being able to get a service manual really sucks. I could look up the values myself.

Tish, AA4HA