Re: CB amplifiers RM-Italy KL203P

ajparent1/KB1GMX <kb1gmx@...>


Its not so much what they use but how they use them.

I have a Silconix 100W SS (literally CB) amp.  Got it cheap for modding.  Base design is
EB63/Granberg with shortcuts and omissions.   Only a few things wrong with it.  Class B
zero bias (no bias circuit at all) so it had serious crossover distortion Add a regulated bias
and that cleans up. Then it needed varying drive depending on frequency and a seriously
bad input SWR at all frequencies from 3-30mhz.  New ferrite, equalization network plus
a 2db pad to keep it under 1.7:1.  Remove a half dozen mica caps factory installed to
try and calm the amp, added feedback.  Remove the useless RX preamp as it was
noisy and excessive gain.   Add switched LPF.

So why buy it?  The transistors were good (MFR454s), the heatsink and board were good,
and the TR relay worked.   Use it as was, not on a bet (it worked but RF dirty!).   Once I got
done it was a nice clean 13db amp that could run at 100W easily with 5W drive.

Way to many out there like that.


Re: ubitx first power up

Mark, KE6BB

Take a look at this:

I haven't tried to set the BFO in my uBitX, so I can't really vouch to this, but it makes sense and is easy to follow.  It appears that it would affect both RX and TX, except TX in CW mode since that bypasses the BFO and uses Clock 2 from the Raduino directly.  

Re: UBITX Touch Control TFT Display


 I have my TFT Display working fine. PTT and all.

I have a question regarding bfo calibration.  I am able to align it but unable to Save the bfo caiibration.  I press the V
Save button on the screen and it quicky flashes.  Then when I turn the radio off and back on, it reverts to a default, i think.   I lose my previous calibrations. 

Also, should I have t save LSB cal.  and also USB Cal. separatly?


Re: Latest Build, Mods and results.

brad martin

Just taking a guess that it’s a push button wired to the CW Jack that when pushed its transmits CW as if your holding down a straight key. At least that’s how I’m planning on doing it this weekend.


On Tue, Jun 12, 2018 at 5:53 PM Nick VK4PLN <nickpullen@...> wrote:
On Tue, Jun 12, 2018 at 11:08 am, <Mharpen@...> wrote:
push button switch to produce a carrier
Mike, could you please share details on how you did this?


Re: Latest Build, Mods and results.

Nick VK4PP

On Tue, Jun 12, 2018 at 11:08 am, <Mharpen@...> wrote:
push button switch to produce a carrier
Mike, could you please share details on how you did this?


Re: CB amplifiers RM-Italy KL203P

Russ KG0BK

I ordered one just to have some more "fun" with.
Being a broadcast engineer I love to rework something to make it work with something else,
The one I ordered says from 20 mhz to 30 mhz it will do 250 watts.
Power output drops down below 20mhz.
Should be fun to play with.
Should have it by Friday the 15th.
I'll play with it over the weekend and post comments.

Russ     KG0BK

Re: uBITX Version 4 first attempt #ubitx-help #ubitx

ajparent1/KB1GMX <kb1gmx@...>

Can't comment on the audio.  It s been changed for V4.  However if you expecting a lot of hiss
that not something it does.  Hook it to an antenna and tune around to see.  You should hear
an increase in noise just putting antenna on it and depending on the band, stations.  The
receiver was designed to be quiet, that means low internally generated noise.

I think during the transmission tone there is a spot where you measure the frequency or compare it to
WWV at 10mhz.
Its not unique to V4.  I suspect if you read around you answer is there.

Best I can do as I took a very different path to calibration.


Re: No Power


Many Thanks Ian.

You have help me to solve the problem. Firstly I have been pressing PTT and then keying up. When you described the changes I should expect and as I had no change just keying I checked the commercial keying lead and it had an OC earth connection. I had previously just checked the inner.

Repaired and it popped into life.

Power out is low but there are many suggestions for setting bias and many other ideas.

Getting 2 W on 80M and 40M but .5W on 15M

This is a fantastic piece of learning, even if mine was a basic one, relying on a commercial lead.

Thanks to all and now more trawling and reading so I can get it digital.

Peter Paul Fox G8HAV
Mid-Cheshire Amateur Radio Society
5 Llandovery Close
Cheshire CW7 1NA 

Group Controller
Dane Valley RAYNET 
Tel: 01606553401 (H)
Tel: 07919315547 (M)

From: <> on behalf of Ian Lee <kd8cec@...>
Sent: 12 June 2018 00:24:36
Subject: Re: [BITX20] No Power

Press CW Key and the screen (second line) should change as shown below.
(This is the same for stock firmware, CEC Firmware)
LSB A: 7.010.000     (receive)
    CW: 7.010.000     (when press cw key)
     TX: 7.010.000     (when press PTT)

If there is no change in the screen, check the CW Jack and CW Line. Especially, check the resistance part attached to CW Jack
If the screen changes as above, please check if you can hear the side tone and the relay sound from the speaker.

You can test it with the scope or spectrum analyzer as follows.
RX : 
  CLK0 : 11.9 to 12 MHz measurement
  CLK2 : It depends on your receive frequency and mode.
              if your mode is 'USB' and 
             44998500 + your Frequency = meaurement frequency
TX :
  CLK0 : 0 Hz (Sleep)
  CLK2 : TX Frequency +- (2000Hz because of applied side tone)


2018-06-12 4:09 GMT+09:00 G8HAV <g8hav@...>:
Thanks Allison and Lee.

There are no changes on the LCD screen. just TX and the frequency in use VFO A. CW is set to ST.

The CW-KCLK#2 R100, and it is not a clean waveform; Scope indicates about 100 mV average.

Hope this helps

Best 73
KD8CEC / Ph.D ian lee
kd8cec@... (my blog)

Learning Arduino

Ken Frazer

For those of you who are trying to learn Arduino programming, edX is offering a course, Arduino Programming, from novice to ninja. The course covers basic Arduino programming and connecting to and controlling external sensor and devices, such as motors. It also talks about using libraries. The house starts June 18, runs for 4 weeks and typically takes 2 - 3 hours per week of your time. It is also free! 


ND6T and K5BCQ = Genius

Bill Carpenter

I just finished building and installing the click eliminator in my uBITX and to my utter and absolutes amazement it worked the first time!  I am an experienced kit builder but other then very simple mods and/or repairs to my K3 and KPA500 I have never done anything with SMT stuff.  But the very well put together kit by Kees and the detailed instructions from Don really made it much easier than I thought it would be.  The board ain't pretty what with a few not-so-straight components because I was afraid to move stuff around too much but it works!  Just worked a 2 in VA and got a 579 with my 2 element quad.


Thanks guys!   May take a while before I try the AGC kit but I plan to soon.

73 Bill NZ0T

Re: Instruction Manual needs revision #ubitx


Does this tune up process work for Align the master clock on the version 4?   When I press the encoder knob it begins to transmit.

Re: Spurs for Dummies? #ubitx-help

ajparent1/KB1GMX <kb1gmx@...>

The spur get visible when the drive is up.  Generally for 10M that means well under 5W.
Some are better than others but I know of three that at 2W on 10M do not pass even at
40db down. measured.

External band pass filters do work like those used by multi-multi contesters.


Re: Latest Build, Mods and results.


FB Ken, I should have included in my list a 330 pF mica cap across the primary of the output former and a push button switch to produce a carrier for tuning an AT or external PA, e.g. my sb200.
Thanks for you interest.
Mike N6CMY

uBITX Version 4 first attempt #ubitx-help #ubitx


I was very excited to get my kit - I am pretty novice, but have a firm grasp of basic electronic theory - I followed the direction from HF Signals, and had it up and running pretty quickly,  its mounted in an old Midland  CB Case and using a Baofeng handmic  (MIC Only)  Speaker is the old midland speaker. I have the VER 4 with no Audio IC On the board and here are my issues:

1. Very VERY Quiet audio using the internal speaker or an small amplified stereo speaker.

2. The Calibration for the 25MHz crystal doesn't work at all like the directions -  I enter the menu and it says setup, turn to on then move to calibrate and hit the button, it tells me to turn exactly to 10 MHz, and a second later begins to transmit -  I hit the PTT Button and get rewarded with a sidetone that is Very loud from the speaker -  I put it on a dummy load, listened with my IC 746 unhooked from an antenna and try to match the sidetone with the noise from the Icom .   

Is this a thing with the V4? 
I am not confident enough to reload the firmware but have messed with the Calibration and BFO SO much things SSB Sounds Horrible!  Ill try to post a video tonight.

Re: Channel to talk in

Arv Evans

Richard  KB3VGW

Please explain more.
The URLs appear to be a group of some sort that requires sign-up for membership.

Arv  K7HKL

On Tue, Jun 12, 2018 at 8:50 AM Richard E Neese <kb3vgw@...> wrote: 

channel to discuss ham builds

Re: Latest Build, Mods and results.

Ken Peck <kenbpeck@...>

Thanks so much for sharing this.  I have been trying to assemble a list  of the mods that I want to do, and you just saved me the trouble!  Very nicely done!

Channel to talk in

Richard E Neese <kb3vgw@...>

Re: RF power chain mods and improvements..

ajparent1/KB1GMX <kb1gmx@...>

makes sense to reuse parts where possible.

My experience with output transformers is more ferrite the better.
However the 2:4 turn transformers at 12-13V had very poor efficiency 
as in under 40% and a lot of heating and the linearity was also poor.
Didn't make any difference which device.

Note I  measure the current to the finals alone since the board provides
the separate feed.  As a result anything over 2A for 10W was deemed 
not good (under 50%) and with the 2:3 and 2:4 I was seeing typically
2.6to 3A again for only 10W out.   Going from 43 to 61 ferrite made little
difference if the ferrite was enough except at 80m.   A transmission
line transformer 1:1 hooked in with DC blocking caps (.1uf 100V)  as
a balanced to unbalanced was  remarkably good on a BN43-6802 at 10W.
Most cases of ferrite heating it was the wire or how it was wound had
a greater effect.


Re: Spurs for Dummies? #ubitx-help

Tom, wb6b

Someone was good enough to email me and let me know the uBITX does seem to meet the -43DB down specification. So, I'm doing WSPR on 15,12 and 10M now. I did back down the audio drive level a little more, just as a precaution. 

However, now that I discovered a way to switch one more filter with the relays that are already on the board, maybe I'll try putting a 160M lowpass filter there.

Thinking about how to reduce the spur was fun though. Even pondered bypassing the 45Mhz filter when transmitting on 15, 12 and 10 meters, and using the 12Mhz chain all the way to the mixer driven by CLK#2. Looked like it required a couple of switchable hi-pass filters on the output filters and, therefore, an additional relay, so no panacea. 

Thought experiments are no substitute for breaking out the soldering iron and trying some things, but, thought or solder, this is the type of thing that makes this transceiver fun to have. 

Tom, wb6b

Re: ND6T AGC implementation for uBIT-X

Dennis Yancey <bigbluedry@...>

Just sent you PayPal for 2 kits of each... 
72, God bless