Don

28 watts on 80m?? most of us are around 10 watts - could be an inaccurate power meter - or if you really are doing 20-some watts you could be over-driving badly.?

notice I am suspicious that relay itself may be still okay ....

you might have some RF getting into raduino that is locking it on transmit.? at the same time, its not wise to make this much RF with the ubitx - you could be jamming all kinds of fellow hams - for not much benefit on FT8.? if it does not lock up when doing SSB voice - another clue it may merely be too much drive into the PA.?

much better to solve it with an adjustment than to take the ubitx into unnecessary surgery!?

Curt

I have a bunch. I can mail you a couple.

I'm glad you found the answer. I looked at the schematic trying to make a suggestion on what to check but I have no experience with the ubitx. There has been quite a few Cobra mikes used over the last 10 years or so. The main thing to watch is not to overdrive the bitx mike input.
Leonard

Go here for schematic and Arduino sketch:?

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Those relays are only rated for two amps @ a not very high voltage; Contacts will eventually wear out on any relay. ?

I have a V3 uBITX that was stuck in TX last night...until I opened the rig up and tapped on the relays to "correct" the problem temporarily. Does anyone know which relay is to blame, and what the replacement is for it? Until this, it had been perfect for more than a year and a half.?



John KB2HSH?

I don't think anyone has mentioned the nanoVNA.? These go from 50 kHz up to 900 MHz, color touch screen, built with rechargable battery and PC sw.? They cost less than 70 USD.? Look at?/g/nanovna-users/

It is strong competition I am afraid for the antuino,? Though I will probably still get an antuino because it will no doubt be the learning and experimentation platform that the BitX radios have become.

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Success.? The problem turned out to be a short between the mic audio line and ground.? Sunil from amateurradiokits.in had sent me a second front panel PCB after I reported my initial problem to him. (His customer services has been awesome and very responsive.)

I could not figure out where the short was - so I wired up a the new PCB - using a smaller iron tip and smaller gauge solder.? No short this time.? I can report that the Uniden/Cobra mic with the 4 pin connector works fine - completely unmodified. ??

Here is a video of the completed rig receiving (sans the send/receive LED which I still have to wire up)



Thanks everyone for the help and advice. ?

Dean
KK4DAS

Curt -- I can reflow each pin if I pull up my pants and stop being a whousssssss.

Good implyed question on the drive level. SWR meter says 28w on wspr on 80m, which means two full minutes of hard duty. ?But I don't know what band it was on when it locks up. ? I was so freeked about how it could be in drive when there was no TX command from my computer, a disconnected sound card, a reboot, a physical turn off/on, that I didn't notice what the band or pwr level was. I feel silly now not noticing that.?

I'll look for any anomolies on the board. ?The "case" has a lot of air flow, so something could have landed where it wasn't supposed to be.?

The lock up is seemingly random, so I can't make it misbehave on command (yet). ?If it keeps up, I'm sure that even I will figure out the pattern. hahah. ?This is the third time so far.?

If i decide to replace it, I assume the required relay is the axicom ?V23105A5403A201 discused (endlessly) in previous threads?

Given that I may need only one, there must be some uBITX builder who got 5 or 10 and would send me 1 or 2 (pleaseeeee..)?

Don
km4udx

I've been reading the topics regarding the ssm2167 with much interest.? So finally I integrated the board into my ubitx v5. I ended up with a trimmer on the output of the board, and pots on the compression, and noise gates.? ?The problem I ran into is that on the air, rotating the 100K pot I had for compression had little to no effect, but I was getting compression as it was clearly audible on the air.?

I read the data sheet more thoroughly on the ssm2167 and found that the input voltage has to be quite low. -20 to -30 dBV or so.. measuring the electret microphone output on the scope, yielded much higher.. aha..I thought.. I need yet another pot to trim the input voltage. I still needed the 5V to get to the electret so I wanted the trimmer past the 0.1 uF on the board..:-(? so I took of the 0.1 uf cap off the board, and made connections for the trimmer post 0.1 uF cap. So now 3 pots and one trimmer. Trimmer adjusts the output voltage, pots are input voltage to the board, compression and noise gate.? ?On the air..no compression sounds like no compression.. and turning up the pot makes now a profound difference in on the air sound with a LOT of punch. the Power meter goes way up with compression now. What I believe was happening is that the input was so high that I was in the limiting portion of the transfer curve for the ssm2167, and now I'm back in the linear portion, and all is well!? My problem is that it would really be good to have the trimmers on a board, so maybe I'll design a board to accommodate the changes.?
73
Brad N8YG

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The 12/11mhz crystal filter is after all IF amps on receive.
The IF amps are operating at very low signal levels, most of the gain is in the audio amps.
It's the audio pre-amp (a 2n3904 just before the volume control) that overloads first,
by a very wide margin:? /g/BITX20/topic/5945215
That thread is about the Bitx40, but the uBitx will have the same issue.

So, if you have a very strong CW station 500 hz away from the weak signal you are trying to hear,
the strong signal will cause audio distortion in that audio pre-amp and any audio filter
that follows the pre-amp won't be able to clean it up.

The solution is to have a choice of wide crystal filter for SSB, and narrow for CW.
But that's not a big deal for most of us, easier to implement the audio filter for CW.


Jerry, KE7ER
?
Jerry, KE7ER

Don

First before we assume its a bad relay, reflow each pin and also reduce the transmit drive level. You never know the relay may be okay. I assume you tried more than one band? Make sure you don't have a small strand of wire to blame for this mishap.

Curt

On Tue, Aug 13, 2019 at 05:50 AM, Jack Purdum wrote:

Inexpensive DSP is incorporated into the JackAl board.

The JackAl board looks like it is a good all in one upgrade to the uBitx.?

So it looks like, in all but the more extreme cases, people are happy with DSP audio bandpass filters. Crystal CW filters can provide some additional protection from overloading from a strong close by frequency signal.

It would seem the reason for this is, the crystal filter may filter out the strong unwanted signal while the signals are still in the first stages of the IF chain. The signals are still relatively weak at this point and the undesired signal is removed before it can get amplified to the point that overloading starts to occur.?

Tom, wb6b

On Tue, Aug 13, 2019 at 07:42 AM, MadRadioModder wrote:

I use my own coded version of this thing

That looks like a cool implementation. Is your audio bandpass filter stand alone or is it an add-on to the Sotabeams filter board?

It sounds like it is a stand alone DSP filter and display.

Is the code on GitHub or somewhere?

Tom, wb6b

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You are welcome! Just learning myself.