[GPS_Standard] Introduction

[Bert, VE2ZAZ]

Hi Zack,

Welcome to this list. I can see you are already sharing your thoughts, which
is good. That's the intent of the mailing list. Thanks.

Regarding the LTC1485 vs LTC485, the two units are almost the same and can
be interchanged in our application. The differences seem to be in the ESD
protection, the LTC1485 being specified up to 10KV. Also, the 1485's
receiver is a little bit more sensitive on its input: 60mV vs 70mV. But in
our application, it shouldn't matter since most OCXOs have a much higher
swing anyway.

73s, and Happy Holidays!

Bert, VE2ZAZ

----- Original Message -----
From: "Zack Widup" <w9sz at prairienet.org>
To: <gps_standard at mailman.qth.net>
Sent: Sunday, December 17, 2006 9:53 PM
Subject: [GPS_Standard] Introduction


Hi All,

I'm new to this group and this is my first posting here.

I made a couple boards from the PDF files of the circuit patterns that
Bert has supplied.  I also programmed a couple PIC's already for them. I
can post some photos at some future date.

I have a few Isotemp model 118 OCXO's that I got on eBay for about $15
each.  One was DOA but I have three that work.  These are very stable
units, warm up in about 15 minutes and have a 0.3 ppm variation with a
control voltage of 8 volts supplied by the OCXO, negative slope.  So I
plan on trying one of them out with the circuit.  I also plan on getting
an HP10811 unit on eBay to play around with.

I also have a bunch of Jupiter 12 GPS engines around here and will try the
circuit using a couple of them.

I do have one question - I ordered a couple LTC1485's frmo Digikey and
they accidentally sent me LTC485's.  They are sending me the 1485's but I
wonder if the 485's will also work in the circuit?

I'll let you all know how this works out when I get it all put together.

I plan on using these as reference oscillators for microwave transverters.
I have all my transverter LO's from 2304 through 10368 MHz phase-locked
to a 10 MHz source.  The Isotemp OCXO's have been very stable and accurate
as free-running devices so far but I think the extra accuracy will come
in handy as I go up the bands to 24 GHz, 47 GHz, etc.

73, Zack W9SZ

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