I also have both (two RbO's and 4 GPSDO's). I'll take the GPSDO any day.
73, Dick, W1KSZ
On 2/18/2013 7:51 PM, Brian Lloyd wrote:
On Mon, Feb 18, 2013 at 11:23 AM, Richard Solomon <w1...@earthlink.net
<mailto:w1...@earthlink.net>> wrote:
RbO's are nice, but they have to be tweaked every so often.
I guess it depends on what you mean. The average Rb reference
oscillator is more accurate even when "uncalibrated" than most people
have ability to measure. Once the unit achieves initial lock it is
already better than 5e-8 (0.5Hz at 10MHz) and headed for something on
the order of 3e-11 (less than 1 millihertz at 10MHz). After all, the
total adjustment range is only +/- 0.015 Hz at 10MHz. So I think that,
even for people trying to win the FMT, an uncalibrated Rb reference is
going to be good enough.
And here's a hint: that error is less than the tuning error in the
Flex radios on most frequencies.
Not so with a GPSDO.
Again, you have to understand the nature of the beast. The Rb
reference usually has better short term stability than the GPSDO. Of
course, the GPSDO has better long-term stability because it is being
corrected over time. But for ease-of-use, it is really hard to beat
the Rb reference.
(I have and use both.)
The simplest way is to get a Trimble Thunderbolt.
They have been as low as $75 over on the "evil empire" (I bought
two at that price). You do need an external antenna, but you need
an even bigger one for the radio !!
73, Dick, W1KSZ
--
Brian Lloyd, WB6RQN/J79BPL
3191 Western Dr.
Cameron Park, CA 95682
br...@lloyd.com <mailto:br...@lloyd.com>
+1.767.617.1365 (Dominica)
+1.916.877.5067 (USA)
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