[Premium-Rx] RE: HRO-600 Help

[Carcia, Francis A HS]

I have a few of those old MECL chips floating around if you need anything.
They may be on boards though
or used but who cares as long as they function.  fc

-----Original Message-----
From: w3jn [mailto:w3jn at direcway.com]
Sent: Monday, March 28, 2005 7:59 PM
To: James C. Garland; premium-rx at ml.skirrow.org
Subject: Re: [Premium-Rx] RE: HRO-600 Help


Jim - let us know if we can help.  You need to have a working ref
oscillator,  a VCO that can be pulled into the proper range, a working loop
filter, and the working logic including phase detector.  A 'scope can
pinpoint the problem easily.
 
73 John

----- Original Message ----- 
From: James C.  <mailto:4cx250b at muohio.edu> Garland 
To: premium-rx at ml.skirrow.org <mailto:premium-rx at ml.skirrow.org>  
Sent: Monday, March 28, 2005 5:37 PM
Subject: [Premium-Rx] RE: HRO-600 Help

Hi Gang,
Many thanks for your help and suggestions, re tracking down some info on my
HRO-600 synthesizer. I'm especially grateful to Jerry Dowell AI6L for
scanning the data sheets from the (obsolete) Motorola MECL ICs and sending
them to me. Also, thanks to Geoff Fors, who also offered to do the same.
You guys are great!

Once I fabricate a set of extender boards, I'll try reverse-engineering the
synthesizer. I don't know a great deal about synthesizers, but from the
parts count I think this is likely a relatively simple 1970-era  "integer-N
PLL synthesizer." Basically, a voltage-controlled oscillator is divided by N
(an integer selected by the bandswitch) and phase-locked to a reference
oscillator (in this case 5 MHz, which I'm guessing is divided down to 1
MHz). The output of the VCO, depending on the N selected, thus can be
stepped in 1 MHz increments from 56 MHz to 84 MHz, which is the injection
input to the first mixer. I'll know more once I get deeper into the project.

Again, tnx for the help, and I'll let you all know how the project
progesses.

Regards,

Jim Garland W8ZR




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