[App_rpt-users] GPS Locked MACTRAC

[Ken]

One thing you should be aware of is that replacing a crystal with a reflock,
or similar, will increase phase noise and spurious outputs of the attached
PLL. In FM this will probably show up as reduced adjacent channel rejection.
If you are not in a dense-signal environment, this may not be an issue. In
any case, you need to adjust the level of the replacement signal into the
PLL carefully for minimum crud generation. Watching the output of the PLL on
a spectrum analyzer would be a good idea.

 

73

 

Ken

 

From: app_rpt-users-bounces at ohnosec.org
[mailto:app_rpt-users-bounces at ohnosec.org] On Behalf Of Randy Neals
Sent: Friday, January 04, 2013 7:30 PM
To: Ron Simpson
Cc: app_rpt-users at ohnosec.org
Subject: Re: [App_rpt-users] GPS Locked MACTRAC

 


I'm also interested in locking a transmitter frequency to stable reference.
The ICOM FR-6000 repeater which I use has a TI LMX2352 PLL which relies on a
15.3 MHz Crystal Resonator, CR-826 type.

It appears that I might be able to replace the crystal with a reflock board
(Link below), with the reflock generating the 15.3 MHz.
http://www.qsl.net/ct1dmk/reflock.html

Here is an example of a ham reflock'ing a yaesu 817 all-mode radio to a 10
MHz reference input
http://www.vk3hz.net/riglock/FT817_External_Reference.pdf

The 10 MHz reference signal can be from a Rubidium Oscillator or from GPS
Disciplined Oscillator, both of which are available from eBay.
The Trimble Thunderbolt is a common GPSDO. Some good general info is on
John's web site: http://www.ke5fx.com/tbolt.htm


73,

Randy - VE3RWN / W3RWN

 

On Wed, Jan 2, 2013 at 12:22 PM, Ron Simpson <n6gkj.cm98 at yahoo.com> wrote:


Hey guys, Happy New Year!

Looking for ideas to cleanly phase lock a MAXTRAC. I have the boards, I have
an idea on how I want to do it. Just would like input from those who already
have done it. I looked online for some info but found nothing.

I can break the ref osc tune line and take that signal out. I can pick off
the 14.4 mhz and bring that out, but I want to do it cleanly, not a hatchet
job.

Anyone have pics?

73,
Ron, N6GKJ

Sent from Yahoo! Mail on Android


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