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v6.1 alignment


Mitchel Rought <mitchelrought@...>
 

assembled new v6.1, hooked up antenna and power( battery 12.9v), only receive very strong signals and these are very garbled, tried tuning wwv at 10mhz, no where to be found, paper work says unit was aligned before shipping and not to try alignment, next best step?


--
Mitchel Rought
644 Main street
Chemung, NY 14825
607-742-5426


Evan Hand
 

Mitchel,
There have been a number of people that have run into the issue that you describe.  Too many have been solved by recalibrating to think that all of the boards coming from HFSignals are truly calibrated.  I only wish that there was a way to go back to the factory delivered setting.  Unfortunately, I do not know of a way to do that.  In the process of calibration, unless you document the setting when you save it, there is no way to read the current setting.  This is for the stock software, there are mods that do display the last value saved.  The ones that I know of do not work with the v6 without modification.  I do not have a v6 to experiment.

The best way to recalibrate a v6 is to follow the instructions in the following video:
https://www.youtube.com/watch?v=t6LGXhS4_O8

Note that it does not have to be WWV.  It could be a signal generator that you know is calibrated or an AM radio station that you know the frequency.

It also helps to know what each step is doing.
The first BFO adjustment is taking the audio signal response towards the low end of the audio range.  Note that Ashhar Farhan is adjusting the BFO) so that the "plateau" is towards the low end of the window.
Then with the added volume for the lower frequency, you will hear the signal closer to the beat frequency.
After you have the master frequency set, now you need to readjust the BFO for the best speech response.

You can always go back and tweak the BFO (the last step), but you must adjust the BFO down before you try to re-calibrate the master frequency.

As warned earlier, be sure to document the settings that you save so you can return to them if need be (like when changing out the Nano).

73
Evan
AC9TU


Mitchel Rought
 

Evan
thanks for the information, I was leaning in that direction but wanted to get another opinion in case I overlooked something
being as this was purchased as a kit I wasn't really surprised by this, what good is a  kit without a little head banging anyway
thanks again


Mitchel Rought
 

Evan
went through the voltage checks and one thing I noticed on the spreadsheet is that Q10-Q42 T and R seem to be reversed
Q70 voltage check  collector 1.73v,  base.832v,  emitter .155v
thanks


Mitchel Rought
 

update- re-positioned the negative lead position and Q70 reads normal as do all other voltage checks


Evan Hand
 

Mitchel,

So how did the recalibration go?  That is my first point of improving reception on the uBITX.

73
Evan
AC9TU


Mitchel Rought
 

Evan
all the voltage checks including U2 were fine
drains on irf510  11.94 vdc
I preset the pa bias full cw
mamp readings standby .333, mic keyed .560, after both adj .760
?

     


Evan Hand
 

Mitchel,
I am asking about the original post from you that said you were having issues with receiving.  My post to that was to point you to the Frequency Calibration video by Ashhar Farhan.  The next few emails have been about voltage checks.  I am not sure how we got there.

Please verify what the current issue is with the rig, and verify that you did try the calibration process that Ashhar Farhan outlined in the video.  Here is the link again:
https://www.youtube.com/watch?v=t6LGXhS4_O8

And here is the message that I had sent:
https://groups.io/g/BITX20/message/82181

73
Evan
AC9TU


Mitchel Rought
 

yes I did the alignment and it worked out fine, receiving very well, now just no output power on cw or ssb


Evan Hand
 

Mitchel,
OK, I will assume that you measured Q90, Q911, Q912, Q92, Q93, Q96, Q97, Q94, Q95 voltages while transmitting into a dummy load.  If all of those passed, then I would check that the relays are working on the low pass filters.  The easiest way is with an oscilloscope on TP7, then TP8, and then the antenna.  That would be using CW.  A static test without power would be to verify continuity between TP7 and TP8.  That would verify the 10meter LPF, but none of the others.  You could see if you are getting any power out on 10meters, though that is characteristically much lower than 80meters.  80 is usually above 10watts, while I have measured only 3watts on 10meters.

If you do not have an oscilloscope, then I would suggest using an RF probe.  You can find ways to build one by searching the internet.  Here is a good article on what they are:
http://www.n5ese.com/rfprobe1.htm

It is really important that you do the testing with a dummy load connected, not to an antenna.  Amazon has pre-built 15 watt devices for $16 with Prime delivery.

Since the receiver is working, the transmitter issue would be somewhere between the base of Q90 and the antenna.
73
Evan
AC9TU


Mitchel Rought
 

Evan
thanks for the info, and as my luck is lately, I fired my tectronix scope and no display, guess that's next on my list
73


Evan Hand
 

Mitchel,
Wow, talk about bad luck.  For me, I would start with the test gear, as you may need that to fix the radio.  The alternative is to build/buy and RF probe per the article.  For testing if RF is getting through that should be enough.  Hopefully, you don't fry your multimeter.

Sorry I cannot help with the scope.

Good luck with your repairs.
73
Evan
AC9TU