Re: qcx calibration

Alan de G1FXB

Hi Terry,
I would be interested in the reluctance to using the GPS calibration, it's good not to just follow the last person but share your reasons if you wish.
(Just, as another Alan says, Hans took the trouble to include set up routine in the firmware and it makes it so very easy.)
The GPS doesn't have to be connected full time, connected once at the time of initial alignment it gives you the correct baseline figures at that specific moment.
From then on if you minimise the changes to the U3S or QCX environment then the two reference xtals should remain stable for a number of days,
just behaves as any free running xtal osc.

If you have a known accurate source you could net both your TS520 and ubitx,
WWV is not an absolute standard, NIST gives a far end dependency within the range? of 10-7
ie:- when simply using a beat calibration method that's in the news at the moment it's in the order of 1hz @ 10MHz
Either U3S or QCX could be a benchtop source, and the accuracy figures Hans provided are:-
low numbers of hertz if left free running, with optional GPS discipline it will be sub
hertz level
(Something better than WWV for most tasks, sits on your bench, frequency agile so not limited to spot frequencies & assembled by yourself.....
Cost ?)

Nothing wrong with TS520's, I have a 830 that just keeps on going.....
You don't require the the PA the U3S provides, if you brought the closely related QRP-Labs VFO kit you could interface it to your TS520 the same way as the Trio / Kenwood 2nd VFO accessory they sold at the time.
Likely it will be more stable out of the box, the difference being that it could be optionally GPS locked in the 21st century.
So many choices.....


On 26/07/2019 12:35, Alan G4ZFQ wrote:
on the frequency - do you mean the wsjx display - i do not have an accurate frequency meter..


That's where the GPS makes it easy.? Otherwise you really need to use a frequency standard, either RWM, WWV etc or get to know a WSPR user who is dead on frequency.
You set the U3 or QCX parameter so frequency is correct.

i have been reading both the qcx and u3s manuals but i am leaning towards the qcx cos its appears a bit less complicated than the u3s.? ie the u3s needs 5 v which would need a regulator to use my 12 v battery,

The regulator is simple, you could even get an Ebay module for a few pounds. I see a switch mode module for 99p inc. but linear is better where radio is concerned.
to equal the pa out it needs the 5 w pa.

That really depends, WSPR does very well with a lot less. 5W is often used but most times that is simply far more than required. I've never used more than 1W, my U3, purposely QRP, puts 50mW to the antenna on 10m and got to FY5KE a few weeks ago.
The U3 does get a little more complicated when you go multiband but it is very well documented and lots of experts here to put you right.

you may be interested that my exiting station has two transceivers - a vintage trio ts520se

There was someone recently using a TS520 for WSPR RX, I was surprised it worked, but it was borderline, it was not designed for less than 4Hz of drift in 2 minutes.

73 Alan G4ZFQ

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