¿ªÔÆÌåÓý

  1. BITX20
  2. Topics

uBitx "Shadow"

 

Hello everyone! I would like to share with you some informations, I installed a new Inverted V antenna for 20m and I discovered that my uBitx is transmitting some "shadow" signal along the center frequency. I can't remember seeing this before, when I was using a zig-zag dipole. This is not happening in LSB. Does anyone know what is this if can be somehow corrected ? Picture attached. Thanks!
 

uBitx version ?

Raj

At 18/05/2019, you wrote:

Hello everyone! I would like to share with you some informations, I installed a new Inverted V antenna for 20m and I discovered that my uBitx is transmitting some "shadow" signal along the center frequency. I can't remember seeing this before, when I was using a zig-zag dipole. This is not happening in LSB. Does anyone know what is this if can be somehow corrected ? [] P
 

This looks like a BFO adjustment issue to me.? I believe that the carrier is in the waterfall as well.? Another possibility is the balanced mixer with T7 and D5 may have issues.? You could have a filter issue, not sure how to test that without a spectrum analyser.? Last that I can think of off hand is an error in the nano program, though this is the least likely.

I had a similar issue, though it was on LSB.? Adjusting the BFO solved my issue.

FWIW
73
Evan
AC9TU?
 

Thanks for your advice, Evan./// It's model V4. Thanks!
 

V4: One you do the spur mods these should reduce or go away!

Raj

At 18/05/2019, you wrote:
Thanks for your advice, Evan./// It's model V4. Thanks!
 

Daniel YO8UFO op

Likewise I am thinking it could be your BFO setting - mine was way off when first delivered.? If you listen carefully to SSB you might come to same conclusion that it may need an adjustment.? Instructions are available at HFSignals - BFO adjustment tends to be easier than frequency calibration.? also see this guide at my local club:

??? ubitx calibration INSTRUCTIONS

Raj also brought up the topic of spurious - I have a v4 also.? In a typical v4 there are spurious issues in some of the bands, generally not much more than 10 dB out of compliance.? In mine I installed a circuit board containing a set of 3 relays, to separate input and output relay function.? it fixes spurious at 18 MHz and below (unfortunately the board and kit are not for sale anywhere yet!? I have dropped hints to ubitx 'merchants' to sell it).? my rig was okay 'as delivered' on 80 and 20 meters.? (I have not yet solved spurious above 18 MHz - they are from a different source - Raj I remember uses better relays and some shielded inductors - I am not sure what else.? I am wondering how the shielded inductors will work in conjunction with my relay solution - I need to get some to find out!? other fixes did not work for me without reducing CW output power).?

Enjoy your ubitx - I recommend 20 and 80 meters from what I have experienced with my rig for spurious. ??

Curt
 

As other have said it seems the BFO. You probably need to shift by at least 500hz. This picture is very similar to the one I showed to a professional vendor when I bought from them a 'fully aligned' transceiver ... they gave me money back... I am still wondering what that full meant...


Il 21/mag/2019 18:34, "Curt via Groups.Io" <wb8yyy=[email protected]> ha scritto:
Daniel YO8UFO op

Likewise I am thinking it could be your BFO setting - mine was way off when first delivered.? If you listen carefully to SSB you might come to same conclusion that it may need an adjustment.? Instructions are available at HFSignals - BFO adjustment tends to be easier than frequency calibration.? also see this guide at my local club:

??? ubitx calibration INSTRUCTIONS

Raj also brought up the topic of spurious - I have a v4 also.? In a typical v4 there are spurious issues in some of the bands, generally not much more than 10 dB out of compliance.? In mine I installed a circuit board containing a set of 3 relays, to separate input and output relay function.? it fixes spurious at 18 MHz and below (unfortunately the board and kit are not for sale anywhere yet!? I have dropped hints to ubitx 'merchants' to sell it).? my rig was okay 'as delivered' on 80 and 20 meters.? (I have not yet solved spurious above 18 MHz - they are from a different source - Raj I remember uses better relays and some shielded inductors - I am not sure what else.? I am wondering how the shielded inductors will work in conjunction with my relay solution - I need to get some to find out!? other fixes did not work for me without reducing CW output power).?

Enjoy your ubitx - I recommend 20 and 80 meters from what I have experienced with my rig for spurious. ??

Curt

1 - 7 of 7