5v at reg out. Changed finals. No go.

Hi everyone...

My dev rig has zero output.

Receive is fine. No tx. Finals are hot without xmitting. Fielding ideas while I troubleshoot. I did have it hooked to a linear. It was acting weird and then went. Ideas??

Thanks,

My case came with several pages of 'instruction.'? one of these conveys the 3 places the LED solders to for the PTT illumination.? I am remembering this thing to be way too bright, so I used larger value resistors (maybe 3 or 4X) to feed the LED.?

I do remember a video that was or is posted to ubitx.com - I found it after I am had assembled but it was very useful as I remember.? Then it was on the front page.?

A key assembly hint -- remove the front panel to allow easy mounting of the raduino and other things into the main board.?

Use your ohm-meter so that you properly connect to the SO239 connector.? Yes find which side is ground and of course this goes to outside of the coax (hint the 4 mounting holes are ground).?

When you get assembled and power up, note as many discovered you won't like the display.? There is a trimmer pot on the backside of raduino, slowly adjust it until you see the nice display.? then note you push the main tuning knob to go thru the various menus (this may not be explained anywhere?)

That 4.7k resistor you install allows straight key CW.? It takes a moment to engage into transmit - so at first it will be strange - but once you adapt to its timing it does CW quite well.?

I will stop answering questions you have not asked yet -- hang in there and enjoy the build, pretend its a puzzle!?

Curt

In my experience, "learning" code while trying to accomplish something with it is about as much fun as trying to balance a tennis ball on the end of a piece of strong.? Please feel free to share any lines as you like, and maybe I'll pick up something from working with it.


Tnx,

Ted

Tom,

I find EER interesting mostly because it helps me think about
what SSB is in the time domain.? We normally think of SSB as a band
of simultaneous frequencies roughly 2500 hz wide, but somehow?
that can be represented as the voltage in a single node that varies with time.

This business of the DSBSC modulator flipping carrier phase is interesting
for the same reason.? Curious that the phase change is instantaneous,
though happens only at times when the signal is fully suppressed.
After going through the 12mhz crystal filter to strip off one of the sidebands,
a 1khz audio transmission is now just one sideband that is 1khz away
from the 12mhz bfo, no phase changes, at no time is the signal suppressed,
a pure CW carrier.? Very curious!?

Having spent a career in digital design, I find PWM generation of RF compelling.
Should be possible without much drive to the gates.? Here's a 1000W 440mhz
single stage linear amp, the LDMOS FET's need 10W of drive:
? ??
So seems reasonable that we could do fairly clean PWM for anything up to 30mhz or so.
Unfortunately, that's several hundred dollars worth of LDMOS FET's,
though I certainly don't need 1000W.

Hmm, maybe play with IRF510's generating RF for the 472khz band?

Jerry, KE7ER

All,

?Choosing? to "Enable Adjust CW Frequency" got me closer (200 Hz) away now. Is that close enough or do I need to adjust the "CW Freq Adjust value" ? I tried adjusting the BFO and that didn't see to do much.

Thanks
73's

Mike WA3O

Where does the led connect to? In photos it seems to connect to the underside of the main board.

My compressor/limiter?is a dual opamp circuit with the second unit as a unity gain current buffer. There is an output control before that stage. So, it from the above discussion I take it that I will need some series resistance after that stage in addition to the level control I already have before it. I'll try a 50K linear pot.

Thanks for the replies.

Fred

The manual for the module says it has been adapted to the ubitx, and it looks to me like it would work readily enough since it is audio only.??

That is interesting to ponder. I've been up all night working on a client project, so I'm a little fuzzy right now, but is sounds like if you could not control the phase reversals some other way that is more convenient, DC coupling the PSK31 signal to the balanced modulator could be a way to do PSK31.

On your other earlier comments, I think the EER concept interesting (looked at the thread you linked). I have read that the past attempts have been marginal. With the digital signal processing that is now available it would seem it may be possible to do EER well. I wonder if we have reached a point where for small, portable, low power HF SSB transmitters, VHF/UHF power transistors might have reached a low enough price point that we could simply pulse width modulate them at several hundred MHZ to produce SSB signals at HF frequencies. Wonder how hard it would be to drive the gates to switching levels at several hundred MHZ, though. ??

Tom, wb6b

The version you have is the production design. The photos on the website are the prototype revision. After installing it in my own uBitx I realized it was harder then it needed to be so I adjusted the solder pads to make everyone else's life's easier. The only changes are to the pad layout.

73

Tim Keller - KE2GKB

I've got a new problem... and the severe return of an older problem.? Maybe someone has seen this or can explain why it happened.

My BitX40 had a stereo 1/8 jack for audio out.? After all sorts of headaches with cabling connected to it, I replaced it with a mono 1/8 jack, as that was more appropriate (and I have good cables for that).

Once I did that, I now have severe ringing/echo/feedback in the audio - especially when I use my external noise filter (which also serves as agc).? At the same time, the ignition noise and alternator whine has returned almost as bad as when I started.

I'd already replaced the two wires from the board to the original jack with a short length of shielded mono audio cable (rather like found in some computers), and it shouldn't be doing this - replacing that cable (along with re-cabling the wires to the volume control) helped reduce ignition noise and alternator whine? before replacing the jack.

The only thing different is that if I remember right, there was a small disk cap on the stereo jack I removed... I've misplaced it otherwise I'd put it back.? I didn't note the value of it so I don't know what was there - and there is no information I could find indicating what the value should be.? It shouldn't have that much effect anyway based on the schematic, but that's the ONLY real change besides the jack.

Any suggestions or ideas of what is going on?? The radio is useless for what I wanted (as it is right now) - mobile use.? It picks up every hiccup that comes from the automobile electrical system!? (And the ringing/echo/feedback makes volume levels loud enough to understand while driving... difficult.)

Thanks!
Bob
N4FBZ

It appears that you have changed the layout of the solder pads for the switch wires. It does not match the board that I have. Is this a newer design?

Doug WB5TKI

In my case it is probably “0ld School” as I am used to a smooth feel on a tuning dial. If tuning at a medium speed I want to hear the radio signals popping by as I can usually hear and ID a signal opposed to also hearing the mechanical clicking of the detent.
Jim
WA3APC

开云体育

Call me crazy but I find the clicking annoying on a receiver, unless it’s a field radio where the resistance can be an advantage. ?Haven’t seen it on a premium receiver, won’t say none have it.

I have several commercial devices that ALL have encoders with detents.? I have no difficulties operating any of them.? So I have to ask the question why not do the same with your uBITX?

A mod I have done on a couple BitX rigs now is to add a 12v regulator on the line supplying power to the main board and Raduino. Even with a 12v supply the supplied voltage stays up around 11, which is OK and less stressful on the 5v regulator, but you can safely supply up to maybe 20v to the rig, getting the benefit of higher power at the PA, without risking anything else. These regulator chips are pretty self-protective, too, and shut down if they overheat, which is how I discovered that a heat sink is needed on the uBitX with a Nextion display.

=Vic=