[Lowfer] Daytime lowfers

[N8OOU]

JD,

Yes, your correct about the U3S needing to calibrate between 
transmissions. That small gap after the M is about 1 minute long which, 
when it was on the test bench, allowed enough time to let the 
calibration finish with a few seconds to spare.

After the M in the middle segment of Garry's capture, the frequency 
should have been brought back in line. I don't know why that didn't happen.

I am running the standard synth board in both the low and hi beacons. I 
have the OXCO version ready to put in them if the frequency swings too 
much during transmission. I have been holding off putting them in to 
stay within my Solar Power "budget".

I think your captures happened after I relocated the GPS receiver into 
the open and the GPS was bringing the beacon back on frequency. The 
curves up look similar to what I saw here last evening.

I'll be conducting more cold weather testing into a dummy load over the 
next few days.


73   de   N8OOU - Mike Meek

On 11/15/2015 12:48 PM, JD wrote:
> It's been a while since I read the U3s literature, but doesn't the GPS
> correction procedure require an interruption of the output for at least
> several seconds?  From Garry's capture, it doesn't look like that takes
> place very often, which may be why the thermal effects have ample
> opportunity to show up.
>
> Even on the WM HiFER, which starts each ident cycle pretty much right on
> frequency, just the heat build-up of the device being keyed on sometimes
> causes a downward drift before key-up again, and that's a shorter time
> period than I think we're looking at in this case.
>
> Attached is what I saw in SE Kansas last night from a little before
> sunset to an hour after. The pair of curved traces is probably WM, based
> on the spacing of the DFCW dashes matching what Garry captured. For
> reference, here is also what I captured from SIW during roughly the same
> hour and a quarter; same receiver, two different Argo screens, 800 Hz =
> 185.300 kHz within 0.1 Hz.
>
>
>
>
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