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Crystal Identification

Posted: Sun Apr 29, 2018 9:56 am
by NSPD
So I have a quantity of old crystals, I believe these are Motorola. Anyone have any idea what type of radios these would have gone in?

I would like to get a low band PT500, PT400, or GE Porta-Mobil working on 43.04 and 43.00 and I am hoping I may be able to use these.


Image

Re: Crystal Identification

Posted: Sun Apr 29, 2018 4:54 pm
by abbylind
Jake
What is the actual freq stamped on the Xtal? Not the 43.000Mhz
May be able to back track the formula using the Xtal freq. Sometimes the Xtal goes into a TCXO

Re: Crystal Identification

Posted: Sun Apr 29, 2018 5:24 pm
by NSPD
The only markings are:

R43.00
HHK6G

And

T43.00
HHK7K
JAPAN

Re: Crystal Identification

Posted: Sun Apr 29, 2018 6:09 pm
by abbylind
No joy sir sorry,,,,,

Re: Crystal Identification

Posted: Sun Apr 29, 2018 6:26 pm
by abbylind
You might try Bomar Crystal They might be able to run it down for you sir

sales@bomarcrystal.com
Good luck

Re: Crystal Identification

Posted: Wed May 02, 2018 4:14 am
by NSPD
Thanks Fowler.. I think we are leaning toward them being Midland.

Re: Crystal Identification

Posted: Thu May 03, 2018 5:07 am
by fineshot1
Jake - i still have some MT500 low band crystals so let me know
what the crystal freq for 43.04 and 43.00 would be. If I have them
I can let you know.

Re: Crystal Identification

Posted: Sun May 06, 2018 1:36 am
by NSPD
fineshot1 wrote:Jake - i still have some MT500 low band crystals so let me know
what the crystal freq for 43.04 and 43.00 would be. If I have them
I can let you know.
I have been searching online trying to find a way to determine that.. no luck so far but if I do I’ll give you a shout!

Re: Crystal Identification

Posted: Wed May 09, 2018 1:11 pm
by PETNRDX
MT 500 crystals won't work in a PT.
PT transmit is carrier divided by 16.
Receive is much more complicated.
For 42 to 54 mhz the first osc crystal freq equals carrier freq MINUS the second osc.
The second oscillator crystal should be 5.245 for 43.00 to 43.16
But the second oscillator crystal should be 6.155 for 43.18 to 49.14.
You will need to find out which 2nd osc crystal you have.

Re: Crystal Identification

Posted: Wed May 09, 2018 3:58 pm
by NSPD
Great info, thanks!