[ARC5] Drift in BC-453

[pa0pje]

A stable external generator and wsjt-x running on your Linux/Windows/Mac
listening to the beat note will tell you all there is to know.

The max drift for wspr is 4 Hertz in two minutes. If it is more, decodes
will be more or less impossible.

One of the features in WSJT-X is FreqCal which stands for "Frequency
Calibration"

Just tune in to a BC station of which you think you can trust it's
stability (...) an see to it that the resulting audio beat note is 1500 
Hz.

Knowing the exact QRG of the BC station, tune the VFO of the RX 1500 Hz
lower. Be it known that the program's output numbers are given down to a
millihertz! Yes mHz, not MHz...

The second "must have" is exact time, usually syncing with an NTP-time
server is sufficient. Leave your computer's clock to your local time and
check if WSJT-X shows the correct UTC date and UTC time.

Run WSJT-X and press F1 to read the on-line manual or use this link and
search for FreqCal.

http://www.physics.princeton.edu/pulsar/K1JT/wsjtx-doc/wsjtx-main-1.8.0.html

73,
Peter - PA0PJE

PS I run WSJT-X on a Raspberry Pi 3 with Linux Debian Jessie and listen
regularly on 630 meters with a Funcube Dongle Pro+ and an E-probe,
better known as a PA0RDT Mini-Whip, as antenna and already copied
several US stations here.


Op 2017-12-11 21:57 schreef J Mcvey via ARC5:
> The LO stability was a  "best estimate" by tuning in a weak beacon and 
> listening for a while. It didn't seem to move much , if at all.
> I do have real equipment to measure the LO drift, but i haven't got 
> around to doing anything formal yet.Once i do that, I will share my 
> drift measurements with the group.
> BTW the little white compensation cap is present in both.
> 
> 
>      On Monday, December 11, 2017 1:34 PM, Kenneth G. Gordon 
> <kgordon2006 at frontier.com> wrote:
> 
> 
>   On 11 Dec 2017 at 18:19, J Mcvey wrote:
> 
>> 
>> Ken,
>> 
>> using the BFO on CW is OK, once the set warms up of coarse.
>> However the digital modes mentioned are VERY drift sensitive, so it's 
>> a problem.
>> I can see the waterfall going sideways just like the guy in the video.
>> 
>> Even after taking the can apart and cleaning the variable cap 
>> contactors, things
>> did not improve.
>> I changed the external blocking cap, but not the internal one which 
>> tested OK,
>> Maybe that was a mistake?
> 
> I don't think so.
> 
>> Try wspr and JT  on your equipment and see if you get better results. 
>> Wspr is the
>> more popular choice.
> 
> OK. I'll set it up here and give it a try. I'll report back here what 
> the results are. My 630 meter
> antenna is not the best, but since Rudy is not that far from me, I 
> expect decent results.
> 
>> The LO appears to be stable.
> 
> How are you measuring that?
> 
> Later,
> 
> Ken W7EKB
> 
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