Date   
Re: ubitx CW straight key wiring

Dave New, N8SBE
 

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

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

Just sayin'...

73,

-- Dave, N8SBE

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

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 https://ubitx.net/wiring-up-a-paddle-and-straight-key/........
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: experience with Sunil VU3SUA's enclosures #ubitx

Dave New, N8SBE
 

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.

73,

-- 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
To: BITX20@groups.io

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.

Eddie

Re: click fix and squeal on transmit #ubitx

Ben AC1FG
 

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: Off Topic: Gap Antennas

Vince Vielhaber
 

If you can, put in 8.8.8.8 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: µB FT8 Success!

Rob Snow
 

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

https://www.amazon.com/gp/product/B00GWFK7FA

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

Bill Cromwell
 

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:)

73,

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
To: BITX20@groups.io
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!

Allison

--
bark less - wag more

Re: Harmonic performance - SSB vs CW

Warren Allgyer <allgyer@...>
 

Allison
I will try lowering the drive to see if it corrects the problem but I am skeptical. I first noted the problem when probing TP1 with the PA unpowered. The discrepancy is already visible at that point. It is pretty clear the harmonics are being generated at the unbalanced mixer.

WA8TOD

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

Truffies
 

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
To: BITX20@groups.io
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!

Allison

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

ajparent1/kb1gmx
 

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!

Allison

Re: Harmonic performance - SSB vs CW

ajparent1/kb1gmx
 

Warren,

During my sessions testing the amp it was noticed but the 20Mhz and up spur was higher 
on the priority list.

Another thing I ran into with a friend was defective low pass filters.  The toroids had different 
numbers of turns from other units.  

First try lowering the drive (RV1) and look again.  If it drops its the amp flat topping (overdrive)
(can be any stage in the amp up to including the finals.).  That can be voltage starving (less than 
12V at the board) or other problem unnoticed.

It is possible that the first amp Q90 is being over driven as well and reducing RV1 will not help then.

Generally the CW drive was found to be higher than clean levels of SSB drive so it could 
be amp overdrive.  Lowering the DC bias to the mixer during CW TX can help that.  The
Mixer (DBM) is being used as a switch but they can also be used as a variable attenuator
as well.  R114 is the point of adjustment.  Non linear action by the diodes is not an issue
as the driving waveform is square to start with which is why the odd harmonics are stronger
on the display.  Add to that the push pull amps (driver and final) are balanced so the second
and forth are better suppressed but 3 and fifth tend to be the push pull amps weak spot.

Also sweep the 3-5mhz filter to insure its working as expected.  Easy to do with power off
and tracking generator as its then isolated.  Also make sure the correct filter is being
selected, TX-A/B/C should all be selected (relay active).

If the TX amp is at or near compression try turning up the DC power a Volt or so (caution TA2822!).
If the TA2822 is on separate regulated power its safe to go far higher than 13V.

Test first as there are many possible solutions depending on the problem.

Allison

Re: Harmonic performance - SSB vs CW

Jerry Gaffke
 

That's an interesting finding, and seems quite likely correct.
Thanks for looking into that.

One possible solution would be to unbalance either the modulator (as done on the Bitx40 by Allard's mods) 
or the second mixer at D3,D4.  In either case, those harmonics should be stripped out by the 45mhz filter
(also the 12mhz filter, in the case of unbalancing the modulator).  Would require minor hacks to the
firmware to set up the si5351 correctly for CW transmissions after this mod.

Jerry, KE7ER


On Thu, Aug 2, 2018 at 09:26 AM, Warren Allgyer wrote:

I am noting a significant difference in the harmonic suppression in SSB mode versus CW mode. 

The two signals are generated in a very different way. SSB is generated at 45 MHz and mixed down to the final transmit frequency by combining with the first oscillator in the balanced first mixer to make the SSB transmission. In CW the 45 MHz path is disabled and the first oscillator is simply moved to the transmit frequency. The first mixer is unbalanced with a DC bias to allow the first oscillator signal to leak through.

It appears the act of unbalancing this mixer produces harmonics, particularly high order odd harmonics that are clearly in excess of the -43 dBc requirement.

The screenshot shows  the harmonics of an 80 meter transmission at 10 watts. The purple trace is the CW and the blue trace is SSB. Signal source for SSB is a approximately -40 dBV 1 KHz tone with the level adjusted to match the CW carrier level. The SSB signal harmonic suppression is just adequate (green display line) however the CW signal is clearly non-compliant.

I am not sure what to do about it yet but wanted to raise the point. I have done a search on this board since I am new and I do not find this has been reported before..... perhaps I missed it?

WA8TOD

Harmonic performance - SSB vs CW

Warren Allgyer <allgyer@...>
 

I am noting a significant difference in the harmonic suppression in SSB mode versus CW mode. 

The two signals are generated in a very different way. SSB is generated at 45 MHz and mixed down to the final transmit frequency by combining with the first oscillator in the balanced first mixer to make the SSB transmission. In CW the 45 MHz path is disabled and the first oscillator is simply moved to the transmit frequency. The first mixer is unbalanced with a DC bias to allow the first oscillator signal to leak through.

It appears the act of unbalancing this mixer produces harmonics, particularly high order odd harmonics that are clearly in excess of the -43 dBc requirement.

The screenshot shows  the harmonics of an 80 meter transmission at 10 watts. The purple trace is the CW and the blue trace is SSB. Signal source for SSB is a approximately -40 dBV 1 KHz tone with the level adjusted to match the CW carrier level. The SSB signal harmonic suppression is just adequate (green display line) however the CW signal is clearly non-compliant.

I am not sure what to do about it yet but wanted to raise the point. I have done a search on this board since I am new and I do not find this has been reported before..... perhaps I missed it?

WA8TOD

click fix and squeal on transmit #ubitx

Ben AC1FG
 

Hi -- I have had my v3 ubitx working fine, and thought I would install the T/R click fix version 2 from http://www.nd6t.com/uBITX/TR%20Click%20Fix.htm. I'm fairly confident in the circuit I assembled, slightly less confident in the jumpers, trace-cutting, and attachment to the board. The click is still audible in the relay but not in headphones on either transition, and I get a loud squeal on transmit into a dummy load when the volume pot is more than slightly turned up. What should I be looking at to diagnose this?

I noticed continuity between the 12v line and the point marked Rx connection in this section after cutting the trace, which seemed odd:

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

Mark M
 

Printed Wiring Board,  a.k.a. circuit board.

Re: ND6T AGC and Click kit wiring notes

Kees T
 

Looks very nice Nick, good luck with it.

You might also label the "+" via on the 5V input since we had some confusion there, and the other grounds (audio, etc).

73 Kees K5BCQ

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

W7PEA
 


Use the Groups wiki site... https://groups.io/g/BITX20/wiki/home  and make corrections and additions if you feel its needed. 

And what they said, build it vanilla first.

Enjoy, its a fun rig,
W7PEA | Patrick

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

 

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. 

Cheers

Michael VE3WMB 

Re: uBITX HF transceiver and blue MBITX metal case.

Sunil Sankaranarayanan
 

Eddie,
            Check this out(from Google)

How to Open and Extract RAR Files on macOS or Mac OSX ...

https://appletoolbox.com/2015/10/how-to-extract-rar-files-on-mac-osx/
7
Sunil Sankaranarayanan VU2MTM
 
 

Re: ubitx and case for sale

Timothy Fidler
 

FET 2N4091 metal case JFET or equivalent. Must be metal case for freq stab.  Bipolars : MPSH 10 or better use  the  BSX-20 which has a FT of 500 Mhz and very low input capacitance c/w 2n2222.  and get rid of the silly 9v regulator chain use an LM 78L09 regulator chip or similar. TEF