Re: DIGITAL FREQUENCY READOUT

MONEYSMITH
 

THE BOX ABOVE THE uBITX IS MY HB DIGITAL WATT METER AND SWR BRIDGE. THANKS FOR THE REPLY.

W4NFR

On 11/8/2018 1:41 PM, Vince Vielhaber wrote:
Did you check the 25MHz calibration of the si5351?  If that's off, everything will be.

Also, what is the box above your uBitx (the one with the display that has PWR:0 SWR: 0.00 and RF: 0.0)?

Vince.


On 11/08/2018 11:22 AM, MONEYSMITH wrote:
THIS IS WHAT  I SEE WHEN LISTENING TO 7.128

WILLIAM W4NFR



-------- Forwarded Message --------
Subject:     Re: [BITX20] DIGITAL FREQUENCY READOUT
Date:     Thu, 8 Nov 2018 08:19:45 -0800
From:     MONEYSMITH <w4nfr@...>
To:     BITX20@groups.io



THANK YOU FOR THE COMMENTS. I HAVE LEARNED TO LIVE WITH IT. I HAVE TEST
THE OFFSET WITH KNOWN STATIONS

THAT ARE ON FREQUENCY AND MY DISPLAY IS ALWAYS 1 KHZ LOW FROM THE
ACTUAL.  I SUPPOSE THE 1 KHZ OFFSET WORKS

FOR CW AND SSB AND MAY BE THE REASON FOR THE STRANGE THING.


On 11/8/2018 6:46 AM, Mark Pilant wrote:
Hi William.

MAYBE I AM MISSING SOMETHING, BUT ARE ALL uBITX V4.3 RADIOS HAVE A
ONE
KHZ LOW READOUT. FOR EXAMPLE, IF I HAVE A STATION ON 7.150 SELECTED,
IT READS OUT 7.149 FOR CLEAR RECEPTION. IS THIS NORMAL?
The short answer, maybe.  (I apologize if you already know the following;
but for those who do not...)

Digital frequency readout is only as accurate as the calibration of
the sending
and receiving stations.  (I had a recent thread going about the Si5351
calibration.)  I'm assuming you have done the recommended calibration
of your
uBitx.

Even with a calibrated uBitx, there is likely to be some drift due to
thermal
heating from any number of sources: the components themselves, ambient air
temperature, etc.  This being said, it is probably unlikely you would see
a 1 KHz drift.

The other possibility is the sending station is "off", they may say
they are
transmitting on 7.150 MHz, but in reality they are on 7.149 MHz. Without
knowing the calibration of the sending station, it is really impossible to
know for certain.

In the "good ol' days" of analog dials, you simply tuned for the best
reception
and went with that.  (This is one of the reasons, back then, operating
near
the band edges was not recommended :-)  I do it all the time with my
Collins
rigs: get close with the dial and then interpolate the frequency.

My suggestion, if you are confident of your uBitx's calibration, is not to
worry about it and enjoy the contact :-)

73

- Mark  N1VQW




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