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HT1250 problem (sound familiar?)

Posted: Sun Aug 08, 2004 7:18 pm
by KC8NIY
Anyone remember this?:


SRN-1290A
APC 672, 749
October 1999
Deadline: 12-31-00


Memo To: SRN Mailing List

From: Radio Product Group / CGISS

Subject: HT750/HT1250 VHF (136 –174MHz) Range Limitation

Symptoms:

1. Radio will not receive or carrier is noisy when receiving a radiated signal in a location that is within the usual coverage area.

2. Radio transmitted signal will not always cover proper range or is noisy when operating within the usual coverage area.

Please note that this is radiated receiver sensitivity and radiated transmitter power effect. It cannot be tested using the conducted receiver sensitivity or conducted transmitter power measurement procedure.

Potential Problem Radios:

Models Affected: AAH25KDC9AA2AN, AAH25KDC9AA3AN, AAH25KDG9AA4AN,

AAH25KDF9AA5AN, AAH25KDH9AA6AN

Serial Numbers: 672TYWxxxx through 672TZRxxxx

749TYWxxxx through 749TZRxxxx

Cause:

The radio is exhibiting excessive processor noise. The antenna matching circuit needed to be optimized.

Corrective Action:

Two radio design improvements have occurred.

1. Improve the radio code to decrease processor noise.

2. Improve the antenna matching circuit to provide a better power transfer from the antenna to the harmonic filter.

HT750/HT1250 VHF radios with the serial numbers above may exhibit poor range symptoms. This depends on the range of operation.

HT750/HT1250 radios that exhibit poor range must be sent to the Radio Support Center for repair.
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Well, I'm one of the lucky individuals to fall into this category after recently picking up one of these radios that was never upgraded. So I pose a couple questions: Does anyone know how much this is going to cost? Will CPS R04.00.00 still work after the upgrade is completed? Will the gain antenna recommended work on 144-148 TX without damaging the PA?

Thanks in advance for any help, I'm pretty frustrated!

Re: HT1250 problem (sound familiar?)

Posted: Sun Aug 08, 2004 7:30 pm
by Josh
I know how you feel because I was in the same boat last year....that's what I get for buying off of eBay...

I was able to get the repair work done for free under the SRN, batboard user 'Charlie', Charlie Gamble- helped me out immensely.

Unfortunately, after the repair, the scan feature was still noisy. Regardless, my HT1250 just a few weeks ago took an RX crap and doesn't RX barely at all for some reason.

My best advice would be to sell it off and buy another. The old ones are really crappy, for sure.

-Josh

Posted: Mon Aug 09, 2004 6:02 am
by KC8NIY
Thanks for the thoughts Josh.

I gather it's going to be an expensive journey to get this taken care of. I'm not going to sell it, because I'll have to disclose the problem with it, which means I'm going to take a pretty big hit over what I paid for it. Then again, I almost could have bought a new one for what I'm dumping into it cash-wise.

I wish I would have read that old thread about 3 weeks ago. Would've asked more questions when I bought it. :evil:

Posted: Mon Aug 09, 2004 6:29 am
by the_muddy_mudskipper
wow - i read your post and now have to ask about the UHF models...

i recently picked up an ht1250ls+ on ebay, after having researched the heck outta them on this forum; i'm pretty familiar with their little idiosyncracies by now...

however, is the problem you describe with the 1250's endemic to the VHF models only?

you've got me worried about my UHF 1250 now... : )

Posted: Mon Aug 09, 2004 9:10 am
by KC8NIY
I never read about any problems with the UHF version. Take a somewhat distant signal and compare it between your 1250 and a scanner. You'll know immediately if you have a problem or not. I just thought it was a tuning issue until I read the thread that Josh started a little over a year ago.

Posted: Tue Aug 10, 2004 6:29 pm
by Garyf629
I had the same problem when we first got the 1250's. We changed the antenna that came with the radio to one from a MT1000, it solved the problem for a while. It later was sent back to Motorola for a sync problem. Don't know if it was related or not. It came back corrected.

Gary
WA1MOW

Posted: Wed Aug 11, 2004 4:05 am
by louis
The improved antenna should help with all versions of the VHF radio.

Also be carefull using the"broad band " uhf antenna at the lower end of (410 ) the band. And they also shio the same antenna for the 450 - 527 radios even though the antenna is 403-490 mhz.