[ARC5] Oscillator Stability and Old-Time gear. (Was OT: Hally Instability)

[Fuqua, Bill L]

  There is some science.
73
Bill wa4lav

________________________________________
From: ARC5 [arc5-bounces at mailman.qth.net] on behalf of Bob via ARC5 [arc5 at mailman.qth.net]
Sent: Monday, November 16, 2015 10:45 PM
To: W9RAN at oneradio.net; arc5 at mailman.qth.net; bob.nash1 at gmail.com
Subject: Re: [ARC5] Oscillator Stability and Old-Time gear. (Was OT: Hally Instability)

Hi to all


        Been an avid readier of the ongoing discussion on receiver drift characteristics of both the old stuff vs the new stuff and it's piqued my curiosity so I thought I'd set up a bunch of my junk on the bench and do a stability comparison on both a lot of the older units, many that have been mentioned, and perhaps a few that have not.  The criteria will be a nominal ambient environment that varies in temperature from around 60 degrees in the early morning to around 70 degrees in the late afternoon.  I'll post the ambient temperature with each tabulated reading.  The reference source will be my Rubidium Standard.  The first run will be in the center of the 80 meter band 3.7 MHz and the second run will be at 14.2 MHz with a third and final run at 29 MHz. The Following receivers will be tested simultaneously :


1  Collins 51J4
2. Collins 75S3B
3. National NC303
4. Hallicrafters SX101A
5 .Hallicrafters SX62A
6. Hallicrafters SX111
7 .Hallicrafters SX146
8 .Hammarlund HQ110
9. Hammarlund HQ129X
10. Hammarlund HQ215
11  Swan 600R Custom
12. Watkins Johnson 8718A


Sorry that I don't have any Drake stuff to test nor am I planning any tests on older or newer transceivers.


All receivers will get a 2 hour warm up before starting the drift tests.  Drift measurements will be based on BFO beats as measured on an HP hight resolution counter with a rubidium time base.  I would imagine that some of the older units may drift out of their pass bands on the third test sequence (29 MHz)  and maybe even on the second test at 14.2 MHz.  Each test phase will last 1 hour. which will hopefully give the later test phases a bit more warm up time.  Total test time will be 2 hours initial and one hour for each phase.  Testing will begin next Monday, Nov 23,


Thank you for the read and perhaps you'd like to speculate on how these boat anchors will tally up at the end.


        73  Bob, KE6F



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