Re-tuning a Radius P50?

ki4iti · Post by **ki4iti** » Tue Jan 24, 2006 2:31 pm

Hello,

I've been given a set of Radius P50 radios, with both channels in the 467 MHz range. Is it possible to re-crystallize and re-tune these units for the 70cm amateur band?

I'll take any information you can offer on these radios, with gratitude.

Josh KI4ITI

kc7gr · Post by **kc7gr** » Tue Jan 24, 2006 4:00 pm

ki4iti wrote:Hello,

I've been given a set of Radius P50 radios, with both channels in the 467 MHz range. Is it possible to re-crystallize and re-tune these units for the 70cm amateur band?

I'll take any information you can offer on these radios, with gratitude.

Josh KI4ITI

Possible? Maybe. Desirable and economical? Probably not.

Consider: Crystals are going to run you a minimum of $25 each. Assuming you want just one amateur 440 repeater and talkaround, that's going to be $75 per radio in parts alone (for two transmit and one receive crystal). If you want a repeater channel and a standard simplex channel, such as 446.500, that's going to run you $100 in crystals (two transmit, two receive).

Next step: Assuming the radios will dip down that far out of band (and that's not a given with this series), you're talking a minimum of a half hour per radio for crystal replacement and full realignment. That means a minimum of an hour, possibly one and a half, which at commercial shop rates of $80/hour or so is going to add up really quick (and that's assuming you can find a commercial shop even willing to do it -- Many will not take a radio out of its designed band, period).

Even my own rate of $40/hour would see you spending $60 on labor, worst case.

Also consider that said realignment requires the proper test equipment (a service monitor) and test jigs (power supply, cabling, etc). Do you have, or have access to, such equipment and the workspace, including power desoldering equipment? Can you still even get a service manual for the P50's? You'll need it, to tell you where the alignment metering and adjustment points are.

As the final nail in the coffin, consider that the Radius P50 is one of the cheapest, nastiest, least-reliable, low-end PoS that Motorola ever created. They were literally built to be throwaways, and parts for them are pretty much nonexistant as they were discontinued nearly a decade ago.

Do you really want to trust your hamateur chatting (possibly even emergency communications) to something like that?

Do yourself a favor. If you want to use a Motorola portable for ham work, get at least an HT600 or MT1000. They're lower-end than the Saber or Jedi series, but you can probably buy a pair of them, with accessories, for about the same (or less, perhaps) than you'd put into those silly P50's getting them recrystalled.

Happy hunting.

n5tbu · Post by **n5tbu** » Tue Jan 24, 2006 4:02 pm

Yes, it is possible to "re crystal" and align to the ham band.
re crystalize is like fingernails on a chalk board to me.
mod

n5tbu · Post by **n5tbu** » Tue Jan 24, 2006 4:10 pm

Bruce,we posted at the same time...you won!
I don't agree on the P50 being a "POS" the rnet series data radio is a real workhorse and uses P50 guts.The P50 is tough and slim to carry,only had a few minor design flaws that were easilly cured with jumper wire.
Crystals from Bomar are only 15 bucks a piece,and if he brings it to a "real "tech,alignment is a breeze even without a manual.
mod

ki4iti · Post by **ki4iti** » Wed Jan 25, 2006 6:59 am

Thanks for your responses. I feel like I have a better idea of what I'm dealing with. I was prepared to hear that it probably wouldn't be economical to do much with the P50's, but I'm glad to know that it can be done - I may choose to work on one of them just for the experience, while I've still got access to good equipment and knowledgeable help. If I break one - well, they couldn't be any less useful than they are now.

Do you really want to trust your hamateur chatting (possibly even emergency communications) to something like that?

I've got other ham gear. An engineer friend of mine had these radios in a drawer, and just gave them to me when he found out I was a ham. Since I'm not licensed to operate on 467.775 or 467.875, I wondered if it would be possible to convert the P50's into something (legally) useful. If it turns out the answer is "no," or "not practically," that's OK.

re crystalize is like fingernails on a chalk board to me.

Sorry! I'll correct my usage in the future.

The P50 is tough and slim to carry,only had a few minor design flaws that were easilly cured with jumper wire.
Crystals from Bomar are only 15 bucks a piece,and if he brings it to a "real "tech,alignment is a breeze even without a manual.

Do you have any details on the wire mods that you'd be willing to share? What do you mean by a "real" tech?

Thanks again,
Josh KI4ITI

n5tbu · Post by **n5tbu** » Wed Jan 25, 2006 8:22 am

By real tech,I guess I meant an older tech that knew his way around a crystal radio,and could tell the rec and tx section without a book.....
bottom charging contacts would open up sometimes and pl or dpl boards sometimes needed jumping out...if yours are ok,leave well enough alone.
mod

kc7gr · Post by **kc7gr** » Wed Jan 25, 2006 10:33 am

n5tbu wrote:Bruce,we posted at the same time...you won!
I don't agree on the P50 being a "POS" the rnet series data radio is a real workhorse and uses P50 guts.The P50 is tough and slim to carry,only had a few minor design flaws that were easilly cured with jumper wire.
Crystals from Bomar are only 15 bucks a piece,and if he brings it to a "real "tech,alignment is a breeze even without a manual.
mod

Ya know what? I realize now I was thinking of the P10. Sorry 'bout that...

I've had problems with Bomar, BTW.

Keep the peace(es).

kc7gr · Post by **kc7gr** » Wed Jan 25, 2006 10:34 am

n5tbu wrote:By real tech,I guess I meant an older tech that knew his way around a crystal radio,and could tell the rec and tx section without a book.....
bottom charging contacts would open up sometimes and pl or dpl boards sometimes needed jumping out...if yours are ok,leave well enough alone.
mod

Ha! Try finding the metering points without any documentation.

Keep the peace(es).

n5tbu · Post by **n5tbu** » Mon Feb 13, 2006 9:00 am

Metering points? Those get the same results as a wattmeter and an ammeter,max watts at min current! for the rec a good ear and a sig gen!
Besides ,I have seen many a tech that couldn't fine tune a peak or a dip(they always missed it by a needle width or 3!)
mod

RADIOMAN2002 · Post by **RADIOMAN2002** » Tue Feb 14, 2006 9:26 am

Just so you know a pair of P-10 radios was used in an Amat satellite about 7 years ago, as far as I know it's still up there doing it.

KE4NYVJR · Post by **KE4NYVJR** » Wed Feb 15, 2006 3:16 pm

P50s are still great radios as long as the tuning slugs are in decent shape. As soon as they get loose, breathing causes them to go out of alignment. I have to retire more P50s that reason than anything. The cost for me to replace the coils, retune and set levels, with labor is not worth it.

Aside from crystal cost, I say go for it.

Re-tuning a Radius P50?

Re-tuning a Radius P50?

Re: Re-tuning a Radius P50?