I've been having fun with my V6 uBITX on the air while I'm waiting on some revised prototype boards to arrive from China.? I'm mainly a CW op and and that usually works best QRP anyway.

Worked K9CT on 40 a couple days ago (got him first call), W3R on 20 yesterday (again, first call) and just a few minutes ago worked W1VE on 20 meters.

My antenna is an end fed Zepp QRP antenna (PAR EndFedZ) and it's only 15 feet off the ground plus it's only about 3 feet above the roof of my house.? I use it mainly for testing when I'm working on things like the uBITX.

I was also using our TSW Teensy 4.0 to NANO plug in adapter on the Factory supplied V6 Raduino.? For the CW ops out there having problems with the keyer timing in the stock firmware, you might consider changing over to the Teensy 4.0 and our latest firmware (available from TSW) as the keyer operates like it should with decent timing.? TX starts immediately on the first character element and if you set CW Delay to 200-250 milliseconds, it comes back to RX fast enough that you don't lose the other guys first character.

All the details are on the TSW website - .? Using the adapter, you might have to bend the 7805 regulator slightly toward the bottom of the factory V6 Raduino in order for the bottom edge to clear the heat sink on the 7805 (Factory has it a bit too close to the NANO socket).

I've been running the rig on the air configured like this for quite some time now and have run into no issues at all regarding the Teensy 4 replacing the NANO as the CPU.? Nice thing is the Teensy 4.0's available program space is only 2 percent full whereas the NANO with current software is around 90 percent full.? Add much more to the NANO's program and there won't be enough room for the program to operate properly.?

Some people are balking at the $19.95 price of the Teensy 4.0 but yet they are willing to spend quite a bit more than that for the NEXTION display which won't fit the mounting holes of the factory case (so they have to modify it anyway) and also the NEXTION's connections are not really "plug and play" either.?

Using the Teensy 4.0 to NANO adapter is about as close to plug and play as you can get except for the need to use a separate key jack for the paddles.? If you don't use the keyer, and just use a hand key or plug in an external keyer you can use the PTT contacts on the microphone connector and you don't have to modify your pretty case.?

No matter what you do there are going to be compromises that will have to be made if you want to really speed up the display and allow for the ILI9341's available font libraries to be used.?

We've kept the screen close to what was original with a few useful additions and ours doesn't take 3-4 seconds to paint the display.? Also ours doesn't repaint the entire display every time you change something and doesn't "blink" when tuning or touching an on-screen button.? This is one of the real advantages of a 600 MHz processor vs the MUCH slower NANO.

Just food for thought ----

Jim, W0EB
TSW Project Coordinator

That EEPROM thing is inside the ATMega328P processor chip used on the Nano.
? ??http://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-7810-Automotive-Microcontrollers-ATmega328P_Datasheet.pdf
It's 512 bytes a of a special kind of memory that that is easy to write to,
but sticks around when power is off.

Jerry

Glad you found it.

Ideally, all firmware would have sanity checks on critical values stored in firmware,
ignore them if they are out of bounds.
And there should be an easy and obvious menu entry to revert to reasonable default values from flash.

Jerry, KE7ER
?

Firmware for a v3 or v4 board mistakenly installed on a v5 or v6
would seriously attenuate 80 and 40 meters, but 10 and 20 meters should be unaffected.
Operation on 80 and 40 would be as if the antenna was disconnected, might damage the IRF510's.

Firmware for v5 or v6 on a v3 or v4 board would allow harmonics out on 80 and 40 meters
since only the 30m filter would be getting used, but again 20 and 10 meters are unaffected

Here's what the routine setTXFilters() does in the firmware for v3,v4 and v5,v6 boards:
To get the symptoms reported (particularly an attenuated 20m) would require two different problems
out in the LPF's.? ?Possible, but seems more likely to be trouble further back in the power amp somewhere.

He reports that CW transmissions are also affected, so not an issue of anything prior to the first mixer at D1,D2.

Jerry, KE7ER

If you are referring to the KD8CEC stand alone s meter and spectrum analyzer, it is on the Hams Key Blog. the latest is here:



Otherwise you can search Hamyskey blog, the messages section in this group, or ubitx.net for other sources.

73
Evan
AC9TU

going to fit a sotabeams? cw filter to my ubitx v5 ,where can i insert this on the board (before lm386 amp) if any one has done this what tracks will i need to break into as i would ike to fit inside the case?? many thanks dave c

anyone got a bix40 pcb bare or (partially) populated they want to part with? dave c? gw0nvf

I have the same question did you ever get a answer?

Mike

Thanks for the reply Jerry and I think you're basically correct.? It's working again.? The problem was the calibration value that was stored in the EEPROM (where ever that?thing may be).? I was implementing a change to the Setup code that would show the stored value when you went back to Setup.? Somehow - and I still don't see how it happened - the calibration value that got stored at some point included the entire frequency plus the calibration value! That made the calibration?way out of range and shut everything down.? Even after reloading the original code the problem persisted because the EEPROM values stayed the same.? Once I had that figured out I forced the EEPROM value back to 875 and the radio started working again.? Now I can re-calibrate and see the stored values when I do.?

Well, I guess you have to expect that kind of stuff to happen when you go messing around with the code....

Simple question:
Are you using the factory V5 firmware?? Confirmed that your board is a V5?

With board changes from V3/4 to V5 the BFO and filter circuits changed.
I haven't gone through the logic mapping of what exactly would happen on the LPF circuits if the wrong version of firmware is used, but it will be problematic.

开云体育

where can i find the lashup for the extra board.? i had not been following that thread and now i would like to add these features to the radio.

dave k7da

I would also check that there is not an issue with one of the relays/LPFs.? Without power connected to the PA (brown power wire), check each band for continuity from the antenna jack to TP7.? You should have a connection for all of the bands.??

The above reasoning is that all of the relays are de-energized for 10 meters (28 MHz).? Not sure why all of the other bands have low output, however it is worth a try.

Just a thought.
73
Evan
AC9TU

Try sending CW, do you get any power out?

If not, my best guess is that the Si5351 is not working for some reason.
You can verify this by bringing a shortwave receiver near your uBitx
(or bringing your uBItx over to a friend's shortwave reciever)
and listening for a carrier within 10khz of 11.059 mhz, being radiated from CLK0.
The uBitx can be in receive mode for this test, doesn't matter what frequency it is trying to receive.

CLK0 is the uBitx BFO signal, the 11.059mhz BFO beats with any incoming signal
that makes it through the 11.059mhz crystal filter.

Jerry, KE7ER

F4huy,

My best guess is a broken or shorted wire in one of the transformers: T8,9,10,11

The fact that you get 2 Watts of SSB at 30mhz is good news,
that shows that everything from the mike to the first mixer at D1,D2 is working fine.

When transmitting CW, CLK#2 is a square wave at the operating frequency.
Mixer D1,D2 is unbalanced by CW-KEY to allow that signal right on through to the final amp.
So this is not an issue with the BFO offset as previously suggested,
this would affect only SSB transmissions, and attenuate all bands equally.

If the receiver works at 3.5mhz, then the low pass filter at L1,2,3,4 should be working fine.
The problem is somewhere between Q90 and the antenna jack.

The signal going into Q90 should be around 0.1 volts pk-pk,
and the voltage increases by roughly a factor of four as it passes through each stage.
Since there are four stages of amplification between Q90 and the IRF510's,
the output from the IRF510's should be roughly 0.1*4*4*4*4 = 25.6 volts pk-pk.

If you have access to a good oscilloscope capable of seeing at least 3.5mhz,
probe the collector (or drain) of each of the four amplification stages.
See if the AC voltage increases with each stage when operating at 3.5mhz.
Compare that to what you see when operating at 30mhz.

If you don't have a scope, I suggest you build a diode RF probe.
Use either one of the first two circuits shown here, they should give equivalent results:
? ??
The first circuit shown is the one most commonly described elsewhere.
The second circuit is easier for most of us to understand.
Note that the smallest AC voltage either circuit can sense will be around 0.3 volts rms,
so it probably will see no signal if you look at the base of Q90.

Many webpages on diode RF probes recommend using a germanium diode,
but those are getting hard to find.? A schottky diode such as the 1n5711 will do fine.
Many dishonest vendors of 1n34 germanium diodes will actually ship a schottky diode instead.
A true 1n34 will be able to see slightly lower level signals than an 1n5711.

When output varies more than it should between bands, my first suspicion
would be the output low pass filters selected by relays KT1, KT2, KT3.
However, all of those output filters are low pass, so all of them should pass
a 3.5mhz signal unmolested even if they got swapped around somehow.

If you do suspect trouble between the IRF510's and the antenna connector,
a good test would be to cut the trace between transformer T11 pin 5 and relay KT1 pin 12,
Then put your wattmeter directly between T11 pin 5 and ground.
The wattmeter will see the raw power coming out of the IRF510's, harmonics and all.
So readings will be a little high, but 3.5mhz should definitely be stronger than 30mhz
since each of the 4 amplifier stages will have more gain at lower frequencies.

Verify that your BNC antenna connector is working with an ohmmeter,?
perhaps go around it by soldering a wire to the PC board till you find this problem.
There have been reports of some BNC connector center pins not making proper contact.


Best Regards,
Jerry Gaffke, KE7ER

Assembled BitX40 is sold. Unbuilt BitX40 v3 with Universal Maroon Case II still available. $100 shipped. CONUS only. PayPal preferred. Thanks for looking...Jim WB2LHP

My V6 suddenly decided not to transmit or receive.? I did do a frequency and BFO adjustment a few days ago and had it dead on frequency.? It is possible that I may now have wiped out the settings on the EEPROM but nothing I have tried to correct that situation makes any difference.? The factory software is installed. The software operates as it should but there is no power going out and no audio coming in even when I transmit on my Kenwood (from previous tests I know that this should be working). There is no burning electronics smell and no visible damage inside the radio (I have made no hardware mods). The speaker still produces the 'live air' sound but there does seem to be an extra 'whistle' in it.? It is very cold and dry here so maybe a static charge problem?? Is the EEPROM onboard the Nano? I don't see any I can recognize on the main board. I can replace the Nano if you think that might be a solution.

Summary: worked fine but stopped suddenly.? No power out at all, no reception even from a nearby transmitter.?

Ideas?