Re: [Repeater-Builder] MVP - PLL

[Bob Dengler]

At 1/5/2007 07:47 AM, you wrote:
 
 Mention was made of how to deal with compensation.  I've built ovens of
 various types, and even used PTC thermistors soldered directly to the case
 of the crystal as a heater, with good results.  I think Bob NO6B did the
 same - you QRV Bob?

Yes, I've been soldering 50 °C PTC thermistors to crystal cases for some 
time.  On my last project using a rather unstable crystal I discovered that 
the PTC thermistors don't provide as much thermal stability as I thought 
(transition not sharp enough?), so I built up a feedback controller based 
on a design out of an old National Semiconductor databook using a dual op 
amp.  I used thermal epoxy to mount a 51 ohm heater resistor  LM34 
temperature sensor onto the crystal.  The circuit is able to hold the 
temperature at the LM34 within +/- 0.2 °F.  Now the only thermal drift I 
see is due to the temperature effect on the oscillator transistor on the 
exciter board.

Bob NO6B

RE: [Repeater-Builder] MVP - PLL

[Jeff DePolo]

Dave KA9FUR designed a complete ICOM replacement board, which included an
audio processor, that fit into a standard PM ICOM shell - plug n' play.  I
have a few of them, but I had some problems which I think Dave latter fixed.
It's probably been close to ten years since I've tinkered with them.
 
Mention was made of how to deal with compensation.  I've built ovens of
various types, and even used PTC thermistors soldered directly to the case
of the crystal as a heater, with good results.  I think Bob NO6B did the
same - you QRV Bob?  Re-creating a complete FM ICOM replacement, such as
what Dave did, including a modulator and compensation (or oven/heater) seems
like it should be pretty easy and cost-effective, and eliminates the need of
trying to find 1C/2C/5C FM ICOM's.
 
 Jeff
 


  _  

From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Steve Smith
Sent: Thursday, January 04, 2007 9:47 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] MVP - PLL


- Original Message - 

From: Kevin Custer mailto:[EMAIL PROTECTED]  
To: Repeater Builder mailto:Repeater-Builder@yahoogroups.com  ; GE-Mastr
II List mailto:[EMAIL PROTECTED]  ; Motorola-Micor List
mailto:[EMAIL PROTECTED]  
Sent: Thursday, January 04, 2007 3:47 PM
Subject: [Repeater-Builder] Using a GE Mastr II PLL ICOM in other equipment,
like a Motorola Micor?



We hope to make a series of professionally built interface modules that 
will make it easy to FM radios like the phase modulated VHF Micor, UHF 
Mastr II, VHF and UHF EXEC II, and the Hamtronics TA series exciters.


Been there done that (Only UHF MII  MVP). The same PCB (audio
processor) is used on both exciters but  and plugged  onto the original ICOM
pins (see attached photo) 
 
In my opinion it's the best thing you can do for these radios! 
 
-Steve
 


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