UHF band 1 Spectra mod to the UHF ham band

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UHF band 1 Spectra mod to the UHF ham band

Postby Jim202 » Sat Jan 28, 2012 1:44 pm

I know this topic has come up a number of times, but I remember someone had managed to move UHF band 1 spectra to operate in the 440 ham band.

Comments on this site, indicate the down side of trying to get the RX front end board to make it into the ham segment. They all say it won't make it to the frequency segment that is needed.

Other comments point to the PA output filter also not making it to the needed frequency segment.

Lastly, I still have not found any firm threads that indicate the ability to move the VCO so that it will work on the UHF ham segment.

Has anyone out there any new input on this topic of moving a UHF band 1 Spectra into the 440 ham band?

Jim
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Re: UHF band 1 Spectra mod to the UHF ham band

Postby Jim202 » Sun Jan 29, 2012 9:13 am

Jim202 wrote:I know this topic has come up a number of times, but I remember someone had managed to move UHF band 1 spectra to operate in the 440 ham band.

Comments on this site, indicate the down side of trying to get the RX front end board to make it into the ham segment. They all say it won't make it to the frequency segment that is needed.

Other comments point to the PA output filter also not making it to the needed frequency segment.

Lastly, I still have not found any firm threads that indicate the ability to move the VCO so that it will work on the UHF ham segment.

Has anyone out there any new input on this topic of moving a UHF band 1 Spectra into the 440 ham band?

Jim



Have obtained the file with the information that I lost from a hard drive crash. Trying to obtain the original author's permission to get it posted to one or more of the technical chat group file sections.

The information involves cutting some of the VCO stipline, working over the RX filter by cutting some off of each of the 5 sections of the filter. It goes on to say the TX output filter probably doesn't need much done to it. Will let everyone know how it all works out.

Jim



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Re: UHF band 1 Spectra mod to the UHF ham band

Postby Jim202 » Mon Jan 30, 2012 4:02 am

Anyone have a manual on the UHF Spectra range 1 radio? There are plenty of manuals around for the range 3 & 4, but no one has come forward with any info on the range 1.

Area of interest is the RF board and the VCO board.

I know these are in the government segment, so the number of manuals available will be limited.

Jim
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Re: UHF band 1 Spectra mod to the UHF ham band

Postby SlimBob » Mon Mar 12, 2012 1:55 am

Why not use them between 420-435MHz, where they were designed from the factory to operate?

Not every Motorola Radio was *designed* to work in a nearby ham band, but many of them do. The R1 UHF Spectra is one of them, the RI MCX100 is another....
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Re: UHF band 1 Spectra mod to the UHF ham band

Postby Jim202 » Mon Mar 12, 2012 3:53 am

SlimBob wrote:Why not use them between 420-435MHz, where they were designed from the factory to operate?

Not every Motorola Radio was *designed* to work in a nearby ham band, but many of them do. The R1 UHF Spectra is one of them, the RI MCX100 is another....



Because there are a ton of these radios collecting dust. The original UHF range 1 is not of much use today with an analog radio. It's a challenge to take and make a radio do something the original design didn't allow for.

Jim
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Re: UHF band 1 Spectra mod to the UHF ham band

Postby kcbooboo » Tue Mar 13, 2012 4:50 am

Jim: I thought the Astro Spectra detailed service manual had all the ranges in it. At least the VCO, RXFE, and PA would be the same as a regular Spectra.

Bob M.
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Re: UHF band 1 Spectra mod to the UHF ham band

Postby Jim202 » Wed Mar 14, 2012 3:46 am

kcbooboo wrote:Jim: I thought the Astro Spectra detailed service manual had all the ranges in it. At least the VCO, RXFE, and PA would be the same as a regular Spectra.

Bob M.


Thanks for the feedback. i did go into the manuals and found the range one and range 2 VCO information. Now to figure out just what it will take to see if the range 1 can be made to work in the 440 ham band.

Jim
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Re: UHF band 1 Spectra mod to the UHF ham band

Postby MattSR » Tue Apr 03, 2012 7:38 pm

Hi Jim

Did you have any luck with this?

Cheers,
Matt
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