[Lowfer] MP & W1VD cal

[Michael Sapp]

Jay wrote:

Mitch

Right on 137780 ... +/- a couple mHz. Will be retasking SpecLab shortly. Can set back up tomorrow if 
you need it.

Jay W1Vd WD2XNS WE2XGR/2 WG2XRS/2


I did a cal here using the 100kHz reference output of a Sprectracom WWVB receiver, which is supposedly good to 10^-10 for accuracy. It cant do 10^-12

anymore on the NBS output since WWVB went to all phase mod last March.....

I tried this once before with a mish-mash of attenuators to take the 100kHz ref signal from 8~10mw  range down 100db or so.  This time

I decided two side-by-side termination resistors (capacitive-proximity coupled) with isolated grounds might be a convenient solution....

http://s1296.photobucket.com/user/wa3tts/media/IMG_3289_zpsea401954.jpg.html

So that improvised attenuator with an additional 20 dB pad gave a usable level in ARGO...

http://s1296.photobucket.com/user/wa3tts/media/cal292713_zps5e3eee56.jpg.html

the first signal being me tweaking to 500.00 Hz on the 100kHz cal signal, then switching to 137.780 kHz and recieving MP at 499.99 Hz.

My modified HD-1420 VLF has a slow downward milli-Hz drift, so apparently the reference in the Spectracom receiver's reference output is spot on......

Thanks guys !!!!

73  Mike wa3tts