开云体育

de k3eui? Barry

Kennett Square PA

Due to my high noise level (over S9) on 80m and 40m, I often will use the? REMOTE SDR? at? k3fef.com (NE PA) for digital sound card nets

like the PA NBEMS or MidAtlantic NBEMS.

To check the accuracy of the k3fef radio, I tune it to? 14.999 MHz and click on USB (upper sideband)

Since ? WWV?? carrier is right on 15.000 MHz, by tuning 1 kHz low on the k3fef VFO, I will hear a steady tone (15.000-14.999)

of 1 kHz or 1000 Hz on the sound card output of k3fef.com? on the internet connection.

This is not the beep beep tones that WWV sends out at the start of each second.

This is the steady ? BEAT FREQ?? of WWV when the K3FEF VFO is purposely tuned 1 kHz low on the k3fef dial.

That audio from k3fef is piped into a second sound card on my home computer, and I use FLDIGI to monitor that sound.

Choose the Fldigi mode? "FREQ ANALYSIS" .??

The waterfall of Fldigi? shows the steady tone close to 1000 Hz

(it also shows the beep-beep audio sounds +/- 500 Hz off but ignore that)

But if the steady tone is not exactly on 1000 Hz on the FLDIGI Waterfall, then the VFO at K3FEF is off just a bit on upper sideband mode.

(do not use AM or? LSB or lower sideband for this test)

I allow the FLDIGI?? FREQ ANALYSIS mode a minute or so to center in on that steady tone, and it tells me that rather than 1000.00 Hz (if k3fef.com VFO were really accurate)

the the audio is at 1004.689 Hz?? (see attached image)

So that tells me that the VFO at the remote SDR K3FEF is "off"? (high) by about 4 or 5 Hz.

That is, the bfo at that radio at k3fef.com? is just a bit "off".

No one likely cares about a 5 Hz "error" at 15 MHz,ut it does throw off copy of MFSK32 signals we use on the NBEMS nets.

I either have to move the center frequency of the FLDIGI WF to the center of the signal coming from k3fef.com

or

I can adjust the VFO frequency at k3fef.com to compensate for the 5 Hz "error" in that VFO.

Either way works.

Not bad!!