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Using FT8 with Bitx40 (and microphonic problem). #bitx40 #ft8

Robert D. Bowers
 

I have a rock-stock BitX40 that I'm trying to get running with FT8 - I've pretty much given up on using this for sideband, as much as I wanted to have a portable 40m rig.  However, FT8 requires upper sideband, and the BitX40 is lower sideband only.  I'm hoping to get FT8 going with it (maybe even PSK31), so I can use it.  It seems sensitive enough, and for FT8 (or other protocols), the power out should be sufficient.

Is there some way to get WSJT-X to function with lower sideband?

Also, a minor problem - the radio board is microphonic when the audio is turned up.  I've gone crazy trying to find the source - it's somewhere in the middle of the board - but I can't find where (no matter how much I tapped with a non-conductive object.  Trying to use the radio for SSB - the feedback is very irritating - like an echo circuit.  (It would be nice to be able to use the radio as intended - if I can get through/past the Kilowatt crowd.)

Any suggestions on what component might be the problem?  (At lower volume levels, you just about cannot tell that it's there.)

Thanks!
Bob
N4FBZ

Viktors Miske
 

See if I get this on the right post this time. (Smartphone not too bright).
Did a quick Google search, found this...


On Wed, Oct 16, 2019, 5:54 PM Robert D. Bowers <n4fbz@...> wrote:
I have a rock-stock BitX40 that I'm trying to get running with FT8 - I've pretty much given up on using this for sideband, as much as I wanted to have a portable 40m rig.  However, FT8 requires upper sideband, and the BitX40 is lower sideband only.  I'm hoping to get FT8 going with it (maybe even PSK31), so I can use it.  It seems sensitive enough, and for FT8 (or other protocols), the power out should be sufficient.

Is there some way to get WSJT-X to function with lower sideband?

Also, a minor problem - the radio board is microphonic when the audio is turned up.  I've gone crazy trying to find the source - it's somewhere in the middle of the board - but I can't find where (no matter how much I tapped with a non-conductive object.  Trying to use the radio for SSB - the feedback is very irritating - like an echo circuit.  (It would be nice to be able to use the radio as intended - if I can get through/past the Kilowatt crowd.)

Any suggestions on what component might be the problem?  (At lower volume levels, you just about cannot tell that it's there.)

Thanks!
Bob
N4FBZ

Robert D. Bowers
 

Thanks.  I've got a working radio and don't want to mod it (I have no use for CW and want it pretty much stock) - I was hoping to learn of a setting in WSJT-X to make it work with LSB.

(I'm sick of having to work on stuff - long story - and would just like to be able to operate - and actually make some contacts.)


On 10/16/19 6:06 PM, Viktors Miske wrote:
See if I get this on the right post this time. (Smartphone not too bright).
Did a quick Google search, found this...


On Wed, Oct 16, 2019, 5:54 PM Robert D. Bowers <n4fbz@...> wrote:
I have a rock-stock BitX40 that I'm trying to get running with FT8 - I've pretty much given up on using this for sideband, as much as I wanted to have a portable 40m rig.  However, FT8 requires upper sideband, and the BitX40 is lower sideband only.  I'm hoping to get FT8 going with it (maybe even PSK31), so I can use it.  It seems sensitive enough, and for FT8 (or other protocols), the power out should be sufficient.

Is there some way to get WSJT-X to function with lower sideband?

Also, a minor problem - the radio board is microphonic when the audio is turned up.  I've gone crazy trying to find the source - it's somewhere in the middle of the board - but I can't find where (no matter how much I tapped with a non-conductive object.  Trying to use the radio for SSB - the feedback is very irritating - like an echo circuit.  (It would be nice to be able to use the radio as intended - if I can get through/past the Kilowatt crowd.)

Any suggestions on what component might be the problem?  (At lower volume levels, you just about cannot tell that it's there.)

Thanks!
Bob
N4FBZ

Vic WA4THR
 

I have found the BitX40 to be a nice SSB rig and I am curious about your feedback problem. Are you hearing yourself through the speaker when transmitting? What microphone are you using?

=Vic=

Robert D. Bowers
 

It's in receive mode only, and somehow coming from the main board.  It is also volume-dependent - the louder the volume, the louder the 'ringing' (actually sounding a bit like an echo chamber).  Up to about 1/2 volume, it's not an issue or even noticeable.  Tapping on components didn't narrow it down that much - somewhere in the middle of the board is about as close as I could get.

I DID pick up a single PSK31 transmission last night - too bad that mode seems to have largely faded away (at least on 40) - it's great for 'weak signal' work - especially if you want to ragchew.  If I remember right, PSK31 isn't dependent on which sideband is being used.  I'm using FLDigi for PSK (and may try other modes), which I think can be set to work with either sideband (worth asking).

I've heard people on the radio, but any attempts to be heard have mostly been futile (only a couple of partial contacts made).  I do know I'm putting out signal - shows up on a meter.  Antenna is a dipole at 50 ft... works fine with my main radio (an ancient TS-520).  I don't know what the issue is - but only two partial contacts in hours of trying - that's not good.

The BitX40 is perfect for emergency communications - I've got it in an old movie film case (like tool box) with battery and external DSP noise filter (also provides 20db or more of AVC - still not always enough) and speaker.  I think I have enough parts to cobble together a little antenna tuner and SWR meter to fit in the case as well.  An easily transportable station in a small (only slightly heavy) box!


On 10/17/19 6:16 AM, Vic WA4THR via Groups.Io wrote:
I have found the BitX40 to be a nice SSB rig and I am curious about your feedback problem. Are you hearing yourself through the speaker when transmitting? What microphone are you using?

=Vic=

Vic WA4THR
 

A couple thoughts about your BitX40. Ashar Farhan suggested that there was possibly too much gain being applied in the LM386 in some applications and that removing the capacitor between pins 1 and 8 might help. Others have said adding a resistor from the volume pot was useful. See the references in https://groups.io/g/BITX20/topic/6827156#34982

Also, the upgrade to the Amunter sketch for the BitX40 does not require any modifications to the rig and still offers tuning benefits. However, with just a few well illustrated and explained additions, which are described in his documentation, you will have many new features like sideband selection, dual VFOs, scanning, and so forth. I highly recommend that software.

=Vic=

Doug W
 

On Fri, Oct 18, 2019 at 04:51 AM, Vic WA4THR wrote:
with just a few well illustrated and explained additions, which are described in his documentation, you will have many new features like sideband selection, dual VFOs, scanning, and so forth. I highly recommend that software.
Allard's sketch for the BITX40 is fantastic https://github.com/amunters/bitx40 With just the addition of a momentary push button you gain a ton of functions including switching to upper side band.
 
--
www.bitxmap.com

Robert D. Bowers
 

Thanks for the link.  I'm very good at research, but lousy at Googling (never seem to find the right search terms to use).  That sounds like it could be a good fix for the feedback, and the description of the symptoms sounds like an extension of what I've been experiencing - including distortion (on very strong signals and higher volumes).

I've had people suggest those other sketches, but don't want all of the bells and whistles - there is only one mod I do plan on making soon and that is to eliminate VFO gallop (except when wanted) - and that's a very simple hardware mod.  I will have to think long and hard, if I want to go through the process of changing firmware - I don't have lots of time to spare to read a lot of server posts just to find out a little tidbit that wasn't clear or dealt-with by the firmware author in the beginning.

I'm trying to find out what might be the best digital mode for QRP emergency communications - since I can't (reliably due to neurological issues) do CW - and I can't seem to get past the kilowatt bunch on SSB.  A low-power laptop and a BitX would be (IMO) ideal - I like FT8, but already know it wouldn't be the answer for emergency communications.

I appreciate the response!

Bob

On 10/18/19 5:51 AM, Vic WA4THR via Groups.Io wrote:
A couple thoughts about your BitX40. Ashar Farhan suggested that there was possibly too much gain being applied in the LM386 in some applications and that removing the capacitor between pins 1 and 8 might help. Others have said adding a resistor from the volume pot was useful. See the references in https://groups.io/g/BITX20/topic/6827156#34982

Also, the upgrade to the Amunter sketch for the BitX40 does not require any modifications to the rig and still offers tuning benefits. However, with just a few well illustrated and explained additions, which are described in his documentation, you will have many new features like sideband selection, dual VFOs, scanning, and so forth. I highly recommend that software.

=Vic=

Werner de Vos
 

JS8CALL will do the job.