Topics

uBitx v6 low ssb transmit rf output low, CW works OK #ubitx #ubitx-help #v6

Andy Page
 

Hi All 
I have my new uBitx V6  :) the CW output is a healthy 8w or more, But the ssb is very low e.g. hardly moving the power meeter on 5w.  I can hear clear audio on another reciver on ssb. I can see no mic gain control. Dose anyone have a list of ouput voltages I will find on the test points on the PCB I could use to start the diagnostic  ? 

Note I am using the provided Mic that came with the kit. I have a scope, Multiy meeter, frequncy counter at hand.

Thanks
Andy

 

Andy,

Everything in power amp is OK. Only start from Mic and move towards the output.

Check first if the receiver is working ?

Raj

If you are replying to me please leave the relevant portion below and delete all below
your signature including the dah-di-dah-di-dah!

At 20-02-20, you wrote:
Hi All
I have my new uBitx V6 :) the CW output is a healthy 8w or more, But the ssb is very low e.g. hardly moving the power meeter on 5w. I can hear clear audio on another reciver on ssb. I can see no mic gain control. Dose anyone have a list of ouput voltages I will find on the test points on the PCB I could use to start the diagnostic ?

Note I am using the provided Mic that came with the kit. I have a scope, Multiy meeter, frequncy counter at hand.

Thanks
Andy

_Dave_ AD0B
 

I would definitely start with the mic cartridge. While the elements work excellent they are prone not working. I think they get voltage spikes when plugging them in. They are very inexpensive and can be replaced for cents.  I have lost maybe half a dozen.  

Don't go messing with the circuitry until you have replaced the cartridge.
--
73
Dave
AD0B
Raduino bracket and Ham_Made_Keys

Curt
 

Andy

unless you have a special peak-reading power meter, most of our power meters are rather insensitive to normal voice modulation.  so it is difficult to determine whether you really have a problem. 

best approach is to use an audio source - a steady audio sine wave input - and then see what your power meter (or scope) reads.  the rig does not have ALC - so it will 'respond' based upon what ampitude it receives. 

on the air, I have had my few watts go nowhere - or had an op come back to me on top of when I said my call a second time - and he seemed annoyed so my signal had to then be fairly strong across the Atlantic. 

possibly your rig is okay.  if you are too worried - build a simple audio oscillator to test it. 

Curt

Andy Page
 

On Thu, Feb 20, 2020 at 02:55 AM, Raj vu2zap wrote:
Hi Raj
Thanks All for the tips I will start with the Mic,  The reciver works fine it's just the rf output on SSB that's low I can clearly hear myself on another reciver. and CW is all good. It's a 
baofeng mic i did plug it in while the radio was on so it might be as Dave said.

Andy
M0JLY  

 

Hi,

Probably a microphone quality control issue.  Check this post:. https://groups.io/g/BITX20/message/74340

73

Mark

Arv Evans
 

Is it possible that the microphone is wired backwards?  The mike cartridge has one
connector pad tied to the shell  (ground).  The other pad should go to the microphone
pull-up resistor that provides DC for the internal FET amplifier. 

Arv  K7HKL
_._


On Thu, Feb 20, 2020 at 2:41 AM Andy Page <andymdpage@...> wrote:
Hi All 
I have my new uBitx V6  :) the CW output is a healthy 8w or more, But the ssb is very low e.g. hardly moving the power meeter on 5w.  I can hear clear audio on another reciver on ssb. I can see no mic gain control. Dose anyone have a list of ouput voltages I will find on the test points on the PCB I could use to start the diagnostic  ? 

Note I am using the provided Mic that came with the kit. I have a scope, Multiy meeter, frequncy counter at hand.

Thanks
Andy

 

Hi Arv,

The new rigs come with Baofeng mics and not capsules.  Older posts here report that some of these are OK, but some have the mic capsule inside blocked by plastic flashing or just misaligned with the sound port.

73,


Mark.

Arv Evans
 

Thanks Mark.  I was not aware that HFSigs had changed from bare capsule to a
commercial microphone. 

Arv
_._

David Wilcox
 

That is typical of ALL the Chinese microphones I have ever seen.  Always open them up and look to see that the mic capsule is free and unhindered. 

David J. Wilcox K8WPE’s iPad

On Feb 21, 2020, at 12:56 PM, Mark - N7EKU <n7eku@...> wrote:

Hi Arv,

The new rigs come with Baofeng mics and not capsules.  Older posts here report that some of these are OK, but some have the mic capsule inside blocked by plastic flashing or just misaligned with the sound port.

73,


Mark.

Mick
 

Also make sure there is a hole in front of the mic. Beofeng mic’s have been known to be constructed without a hole.
73
Mick VA3EPM 

MVS Sarma
 

Misaligned hole might slighy reduce audio and it can be amplified. Main advantage is, accidental  waterfall on the mic doesn't effect the mic directly.

Sarma

On Sat, 22 Feb 2020, 7:13 am Mick, <Mgsebele@...> wrote:
Also make sure there is a hole in front of the mic. Beofeng mic’s have been known to be constructed without a hole.
73
Mick VA3EPM