Re: Ubitx will be here tomorrow. Any suggestions for a Bitx newbie #ubitx

Bill Cromwell <wrcromwell@...>

Hi there..

do step 3 before step 2. Install that resistor first. Then apply power.

4. The software is already 'loaded'.

After you install in a case you will have left me behind. I am not interested in touch screens, etc. Enjoy your new radio:)


Bill KU8H

On 08/02/2018 01:38 PM, Truffies wrote:
I just received my ubitx building this weekend on cardboard to see if works.

Questions on steps

1. build on cardboard
2. power
3 place 4.7k in key jack
4 ? do you need to load software?
5. Final listern test to see bands turning rec.
6. Test in dumb load transmit
7. OK build into a case
8. now ready to modify - AGC
9. LCD touch screen add software first to use screen?
(load hex and how to do in steps please where to find) dumb all new to me

-----Original Message-----
From: ajparent1/KB1GMX
Sent: Aug 2, 2018 1:22 PM
Subject: Re: [BITX20] Ubitx will be here tomorrow. Any suggestions
for a Bitx newbie #ubitx

ITs been said but I will repeat.

Build it first and test. Insure you have the 4.7K in place on the
key jack. Double check wiring.

If you are bench testing before boxing it. Use care to avoid
accidental shorts or wires touching
the wrong thing and outside events like ESD (carpet static!). One
example seen was taped to
a piece of card board to keep everything from moving around, worked
well too.

Use 13.8 volts for testing as its likely a V4 board (discrete
transistor audio amp).

If all goes well you may want mods and to pick out what your box is
to look like.

Good luck!


bark less - wag more

Re: click fix and squeal on transmit #ubitx

Don, ND6T

When the rig is not powered or in the receive mode there should be continuity from the Rx connection point to 12V. through relay K1 contacts 3 and 5. That is normal. The squeal is not!
First step in diagnosis is to check the voltage on the gate of Q3 when in transmit mode. It should be below 1 volt referenced to the ground connection on that board. If not, check to see that the ground connection there has the same potential as the ground plane of the BITX. Then track down the voltage discrepancy. The operation depends on Q3, acting as a gate, being turned off, thus opening that gate. If that gate is allowing the I/O (when in transmit, it is the microphone pre-amp output) to be leaking into the audio output then you will get enough feedback to oscillate. If the gate of Q3 is below 1 volt referenced to the source during transmit then Q3 may be bad. If there is voltage on the source, check your solder connections of R4.
Keep us informed, please. 73, -Don

Re: µB FT8 Success!

Rob Snow

I went a slightly different direction and picked up a cheap temp fan relay from Amazon:

I superglued the probe to one of the finals heatsink and then played with ON temp and hysteresis temp, I settled on 50deg ON and 35deg OFF.  It was $5 for the fan relay + probe and ~$8 for a 12v 2wire fan.  Works great.

73 Rob de AG5OV

Re: Off Topic: Gap Antennas

Vince Vielhaber

If you can, put in for your first name server and see if that does it. That's google's name server.

Vince - K8ZW.

On 08/02/2018 04:02 AM, DaveC wrote:
Thanks guys, Don't think it has anything to do with the EU privacy
issues also cleared out all cookies etc and no change.
It looks like a DNS issue and somewhere in the chain from the masters an
update error is occurring.

73 Dave G8PGO

Re: click fix and squeal on transmit #ubitx


Thanks, Don! In a surprise move, the problem turned out to be uncarefulness on my part. My confidence was misplaced, since I'd used wrong capacitors in a total of four places: both caps in the circuit were 10μf, not 10 nf, and my replacements for C50 and C63 were not polarized. Now that I've replaced all four with the correct caps, the squeal is gone. The click is still audible in the headphones when the volume pot is turned way up, but it's much less than before. I think I'm going to declare this a qualified success and put the radio back in its enclosure.

Re: experience with Sunil VU3SUA's enclosures #ubitx

Dave New

I found out that the MH3 mike that came with my KX2 works peachy plugged into the 3.5mm PTT/MIC jack.  No wiring, no fuss.  The up/down buttons, of course, don't work (they cause PTT), but otherwise, I won't have to come up with an adapter for anything.

So far, using my Picokeyer plugged in to the CW jack, and my Bulldog paddle for CW.  Works peachy, too.

Showed it off at the Detroit Maker Faire (special event station N8M) this past weekend, and it drew a lot of positive comments and questions.  Mine is dark green, and the green LCD sets it off nicely.  Left the lid off so everyone could see how it went together.

I'll be at the MI QRP club picnic this Saturday (1000 to 1400 ET), and running CW/SSB on likely 40 and 20 meters, using my Super Antenna on the picnic table with tuned counterpoise wires.


-- Dave, N8SBE

-------- Original Message --------
Subject: Re: [BITX20] experience with Sunil VU3SUA's enclosures #ubitx
From: "Eddie Esserman" <ee@...>
Date: Wed, August 01, 2018 11:35 pm

Thanks Ian at ? for email.
Making good progress.  Don't think I will be using the digital connections on the back panel, but putting in the board.  Also switching from the panel.
Rest seems pretty well being resolved.  Need to find a good picture of the relay for the TX/RX LED connection.
And wiring the mic connector.  I'll learn Arduino on an easier board.  My first experience, and this is in place and seems to work.  That's another lesson.


Re: ubitx CW straight key wiring

Dave New

Wow.  I missed that completely by using the front panel PCB that came with the enclosure from

Seems like with online resources like that, the schematic and wire-up page could get updated.

Just sayin'...


-- Dave, N8SBE

-------- Original Message --------
Subject: [BITX20] ubitx CW straight key wiring
From: dkuk@...
Date: Wed, August 01, 2018 9:29 pm

I've gone through 2 rounds of blowing finals before I finally found it mentioned that the wiring in the manual for the CW straight key was wrong.
It is also wrong on the website
The resistor and blue wire must be wired to the upper right terminal in both pictures for it to work properly.
With the wiring as pictured my keyers essentially shorted the ring to the sleeve, hard keying the rig.

I would set up my keyer - plug it into the jack on the ubitx, then power the ubitx up,
unaware that as soon as I powered up, the ubitx was keyed until the finals finally fried.

This is the reference from the same web page mentioning the error in the schematic:
"There is an error on the circuit diagram and the wire up instructions for the CW Key.  The
diagrams show the key connected to pin 2 of the key jack. Pin 2 is the RING terminal, not the TIP."

Just wanted to put this out there in case anyone else is going through similar frustration.
I was so frustrated that I was ready to scrap my ubitx.

Re: End Fed antennas w/ uBITX #ubitx

Chuck, N1KGY

On Tue, Jul 31, 2018 at 06:38 AM, Warren Allgyer wrote:
In actual operation these losses would be the best case and would be experienced only when the antenna is a resonant multiple of a half wave. The losses when not terminated in a 2470 ohm resistive load, which would be the case if the antenna were used on any band other than the single resonant band, are far higher. On the order of 8 - 10 dB.
Thank you Warren.  Your VNA and 'scope plots illustrate very clearly why in antenna literature, "all band" doesn't mean what most folks would have it mean - it almost always means "lossy".  Even commercial manufacturers have a difficult time producing a high transformation-ratio UNUN that operates across multiple octaves of frequency with acceptable losses - it's just not an easy set of design objectives to satisfy...  so for casual construction projects it a reasonable design constraint to limit (focus) yourself to making a transformer with minimal losses across ONE octave of frequency.  I.E 1.8~3.6Mhz; 6~12Mhz, and 14~28Mhz.  Even minimizing losses in the 14~28Mhz range can be challenging, due to the very high transformation ratio (1:49) - look very closely at your use case before choosing core materials -

Material #43 isn't  "the best" choice in many cases; in fact I try to avoid it whenever possible below 5Mhz and above 20Mhz because of it's high(er) losses. 
Material #61 yields lower losses than #43 for nearly every application in the 10~30Mhz; and Material #31 has lower losses than #43 in most applications at or below 5Mhz. 
In practical applications, the loss curves of materials #43 and #31 'cross each other' in the ~8Mhz range, so an UNUN | BALUN made for use on 40 Meters can utilize either core material and achieve a respectable loss figure, when all other design limitations are observed.

This is why I strongly recommend designing and building separate matching units for (80)/40/30 meters, and 20/17/15 meters - that way, each can be optimized for minimum losses in the specific band(s) it will be used on.

I would use matching techniques for 12/10/6 Meters which don't employ ferites or iron powdered toroids at all.  Air core coils and/or transmission-line sections are compact enough on these bands; yield very generous matched bandwidth figures; and have much lower losses when compared to the toroidal transformers [tuned and un-tuned] being discussed throughout this thread.


Re: RFI Problem related by routing audio through K3 (uBitx)?

Gwen Patton

From what I've been able to find, if it has silkscreened component locations, it's not a PWB, it's a PCB.

Most people use PCB nowadays.

Additional Boards supplied with Case V3

Don Coulter

Hi everyone,
can anyone please supply the wiring diagrams or photos of the correct connections for thee small pcbs that came with my kit cant find any wiring details anywhere any help would be most gratefully received
73 de Don G4MTR

Re: Harmonic performance - SSB vs CW

Warren Allgyer <allgyer@...>

The signal at TP1, the output of the first mixer is a pure square wave as it is derived directly from the Si5351 in CW mode. The signal in SSB mode is much closer to a sine wave as it is a mix of the Si5351 square wave and the 45 MHz drive that has been filtered by the roofing filter of Y1 and associated components. 

The only filter that the CW signal encounters before the output filters is the 30 MHz LPF between TP1 and TP2. It has a 2 dB point of about 34 MHz in my case so any harmonics below that are unattenuated until after the final.

The obvious way to fix this is to do the CW generation prior to the roofing filter. What is not obvious to me is the best way to do that. As it stands it is pretty messy.


Re: Harmonic performance - SSB vs CW


I it was soemthing easy to try but I'd call it the same as you.  Lots of harmonics
in square waves and little filtering.   

At frequencies below 20MHz the filters at the amp output are the only filter.
Not my favored way, either. 

If there were band pass filters at the amp input this would not be an issue
nor would spurs be an issue.

One way and likely there are many:
An improvement is to move the keying (CW_TX) to the product detector/ TX modulator
and move the BFO to the edge of the pass band and key that.    The easy way is
remove R105  and run a wire from the junction of C1/R104 under the board to
a replacement R105 at the modulator junction C222-1 and the transformer T7.   
Then both the 12 and 45mhz filters can clean it up.  That would be the wire changes.

Doing that requires a code change.  Actually any change that comes immediately
to mind requires that.    The code change would remove the mix of VFO switching
to only the BFO and the signal CW-key would drive the Balanced modulator.  That
works well as It has been done on many other radios.  Code is easier than solder.


Re: any tips for debugging RFI issue? #ubitx-help

Lawrence Galea

You said you are using the coax shield as the counterpoise?
RF pickup on all bands or all bands?
Try changing the length of the LW + or - and use a 1/4λ counterpoise connected to the case.

On Thu, Aug 2, 2018 at 4:23 PM, Michael Babineau <mbabineau.ve3wmb@...> wrote:
Mike :

It certainly sounds like RF getting into where it doesn't belong.  End-fed wires are notorious for bringing RF into the shack.

I would suggest trying to put a ferrite choke on the power leads and keeping them as short as possible.
Any external wires (PTT, Mic, key, power, headphones) might be acting like an antenna and allowing
RF in where it isn't wanted. 

Is there any way that you can try a different coax fed antenna ? Maybe try the same configuration at a friends place where they 
have different antenna setup ?  That would at least allow you to rule out some internal issue in the radio.  If you can't reproduce the
issue elsewhere with a real antenna on it then it is likely something specific to your use of the end-fed wire and resulting RFI. 


Michael VE3WMB 

Re: Ubitx will be here tomorrow. Any suggestions for a Bitx newbie #ubitx


Add in 6b : modify the raduino vanilla software to use kd8cec memory manager and get the settings -so you can put these settings in your other nano with the kd8cec software neesing very few calibration.

to do that :
1-load official raduino sources v4.3
look at it and apply the mod shown on kd8cec site to use memory manager with original firmware (add Memory CAT communication kd8cec compatible -take care the published file is for v3 raduino, on v4 sketch the « case » instruction Is used In places of multiples « if » but you can use the same logic (i will send you the file after returning from hollyday this sunday -but if you know arduino prog it’s easy)
2-apply it on your vanilla nano (working nice, well calibrated)
3-run kd8cec memory manager and retrieve memory data from your board
4-save the datas (write or print the main values -calibration, bfo...)
5-program your New nano with kd8cec firmware and preset the values previously found (it’s perhaps not perfect but might not be totally off-calibration is a true problem, i ve not seen a nice process to do it)
TAKE care the pins on the nano might be reversed (the ch340 on the uper side), I ve  put them in order to be able to insert the nano on 1 side or the other
i hope i m Clear enough (not so easy on a smartphone)

Re: any tips for debugging RFI issue? #ubitx-help


Mike KK7ER,

What form of end fed 1:9 with random wire very bad without counterpoise.
Or resonant half wave (swr under 1.7:1).  FYI if not low at the desired frequency
read the manual and tune it.

FYI: a dipole without a balun or with one and a bad coax routing has RF on the coax
and off center fed is pretty bad too.

Most vertical with out a choke at the entrance are pretty bad as well. A Butternut
HF2V was the only antenna that gave me bites despite 8 radials.  The fix a 
length of LMR240 with about 50 FT50-43 toroids. before it cam into the house
and grounding the sheild.

Solutions, one is a choke balun (air or ferrite) at the shack entrance and also ground it there.
The other is load up all the wire you suggest has RF on it with ferrite.

Then again I ran into that with someone and moving the antenna (he was
literally less than 10ft under it). Didn't help that the coax used had broken off ground
in the connector too.

Insure the lead from the board to the coax connector really has the ground lead to
ground and not swapped.  You laugh...

More than like if the picture is correct... The wires hanging out of it could be as much the cause.

Power supply leads can be an path in.


Re: any tips for debugging RFI issue? #ubitx-help


Forgot one...

Painted box, did you clear the pat at the coax connector and use the star washer?

Same for the board mounting standoffs, All of them.


Re: Ubitx will be here tomorrow. Any suggestions for a Bitx newbie #ubitx


I added a file/photo showing the reversed side mounting pins for nano

Re: any tips for debugging RFI issue? #ubitx-help



I agree with everybody else that your getting RF back down the feed line, it happens bad on my Par EFHW on 20 meters. Thanks for unwittingly giving me a tip on where to buy my case for my uBitx, I haden't thought of Jameco. I just placed the order.


Re: any tips for debugging RFI issue? #ubitx-help



Try changing the length of the coax on the PAR.  Something like 5FT can change that.

For cases Allied Electronics too.  They stock a lot of the Hammond products.


Re: ubitx CW straight key wiring

Gwen Patton

I also "cheated", using Jim W0EB's breakout boards for the sockets and encoder. They're silkscreened with labels for tip, ring, sleeve, so I didn't wire it to "pin 2", I wired it to what is marked as "tip". So I avoided the incorrect instructions entirely.

Best purchase EVAR.

Gwen NG3P