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high pitched wine on 80 and 40 M

jfein2000@...
 

Hi tried to search for this issue on the forum but without success.  My microbitx works on all bands, transmit and receive but I experience a high pitched wine on 80 and 40 meters.  It isn't present on 20 meters or on 160 meters for that matter.  Any suggestions would be much appreciated.  Thanks Jeff
 

 

 

Ian Reeve
 

The original thread is elsewhere but the symptoms disappear when the rig is run from a 12v battery.This points to power supply issues and may be worth a try.I have a uBITX and power it from a gel battery and test have proved that some 12v wall wart power supplies are troublesome with high frequency emissions which are then picked up by the circuitry


From: BITX20@groups.io <BITX20@groups.io> on behalf of jfein2000 via Groups.Io <jfein2000@...>
Sent: Monday, August 26, 2019 7:36:19 AM
To: BITX20@groups.io <BITX20@groups.io>
Subject: [BITX20] high pitched wine on 80 and 40 M
 
Hi tried to search for this issue on the forum but without success.  My microbitx works on all bands, transmit and receive but I experience a high pitched wine on 80 and 40 meters.  It isn't present on 20 meters or on 160 meters for that matter.  Any suggestions would be much appreciated.  Thanks Jeff
 

 

 

jfein2000@...
 

Appreciate the feedback.  I am was running it from a linear power supply.  Tried a wall wart as I read that thread and it was the same...only 80 and 40 m.  It should not be there though with a linear power supply.  It is a Yaesu FP1030.  I have a battery handy and will give it a try to see what happens though.  Thanks Jeff VK3GMO
 

 

 

jfein2000@...
 

G'day Ian, can confirm the whine exists when using a 12 volt battery as well.  :(  Cheers Jeff
 

 

 

John (vk2eta)
 

Hi Jeff,

Not sure which version board you have, but could it be usb/lsb related (despite the 160m absence which I presume was in LSB)?

If it is, I would look at the Arduino clock issue which I suspect should only affects V3 and V4 boards (V5 has a different 2nd IF frequency). 

I have a few post on this subject in this forum.

73, John

jfein2000@...
 

Thanks John,  it is rev 4, 2018 vintage.  It receives on 80 and 40 but the whine in the background is very irritating.  Tried to find any relevant posts by you as noted but without success.  I suspect it is SSB related. 

cheers

jeff

 

 

 

John (vk2eta)
 

Hi Jeff,

Here is the link to the thread.

https://groups.io/g/BITX20/topic/8872690#54576

In summary it was the nano's crystal frequency. 

I changed the nano and it solved the issue.

To see if it's related to this issue just touch the nano's crystal or change slightly the BFO's calibration and the tone will change too.

If it doesn't, it's another issue.

Hope that helps.

Cheers, John

_Dave_ K0MBT
 

I had that whine occur on a V4 uBITX that I purchased used. It was also fairly deaf.  The solution was to change the bfo frequency to stock. It was about 2 kc off. It works well now. 
--
73
Dave
k0mbt
http://veloliner.com/ham/k0mbtkey.pdf

jfein2000@...
 

Thanks Dave and John.  Yes I think the BFO was the issue. Actually got onto that  a few days ago.    Also found if I turned on the attenuator and it went away.  Reset the BFO and seems ok now.  I do notice that it is not very sensitive on receive compared to any of my other radios.  Wonder if that is just how it is? 

cheers Jeff VK3GMO
 

 

 

John (vk2eta)
 

Hi Jeff,

Glad you resolved the issue.

My V3 uBitx is as sensitive as my FT817 with the preamp off.

Could this be a perceived effect of the relative lower audio chain gain of the V4 units, or is it that faint signals are heard on other radios but are "lost in the noise" on the uBitx?

73, John

jfein2000@...
 

May well be.  The audio is too low for the speaker to be of any use.  I recently was able to pick K6MYC from CA who usually comes booming in at 10 or 20 over S9, using headphones.  I will be using powered speakers with it and that should help somewhat.  However I suspect it could be more sensitive....just doesn't feel like it is solely an audio issue.  Given there is iimited alignment functionality not sure how to progress that.  Also very hard to find a decent USB signal in Australia atm with propagation so poor.  It has been awful here for the last week. Cheers Jeff VK3GMO