Original thread was "RX Trouble". ? Sort of a rant here...

I am not superstitious but beginning to believe my uBITX (both factory & CEC firmware) is cursed. Have had issues since first power-up, but now I think the problems are fatal.? Have a lot of time & money in it (Axicom relays, trouble shooting, etc.) but think I might call it quits.? Never had problems with my scratch built rigs.? Had a problem with my K2 build, but fixed that when I discovered a copper whisker (under the coating, I took optical micrographs !) shorting a pair of runs on the control board.
However, the uBITX has been a relative nightmare.

Original issues, to name a few:
Not on frequency, low audio, poor RF sensitivity, pinched audio response (narrow - filter issue?),? very narrow tuning for understandable audio, etc.

I fixed the too low for headphones audio with an off board amplifier.? But, the distortion was even worse from the speaker. I found a power/signal driven oscillation in the external amp and fixed that.? Afterward, the volume was OK and the distortion was somewhat lower - but still not great audio.? The other problems remained.

Observation:
There was (I think, maybe) something oscillating on the board. There was a low level (~700) Hz tone on the audio coming from the board.? Found that with a 'scope, but did not find the source. Also, the 12 MHz crystal filter was rather microphonic - With no received signals lightly tapping crystals produced audio output. Normal?? Not normal?

The TX power was inconsistent with measurements by others.? Got 10 +- watts out on higher bands, dropping a bit as frequency increased.? But, for 40M and below, the power dropped to about 1.5 watts while the supply current was much higher (almost by 1 amp). ? Frustrated with the RX problems, decided to look at the TX power issue using 'scope on TPs in the TX amp stages.
-- The following is when the patient died. No brain activity ;) --
CW keyed the TX for testing but I didn't get far before the fatal problem occurred. After a few short dummy load TX sessions, it stopped keying.?? Immediately noticed a display issue.? The top row was all solid fill characters, nothing on the bottom row. Clocks 0, 1, 2 not there.? The 7805 on the Radiuno is supplying 5 v.? This is a bit subjective, but is does not seem to get quite as hot as initially? -? likely not supplying as much current as before?.
Hoping the cause was somehow corrupt firmware, tried reloading. Xloader appeared to connect and tried to upload, but never left the "uploading" mode - Failed to reload firmware.? The display stayed the same - solid top row, empty bottom row.
Tried uBITX Manager to read.? It appeared to connect, but when "Read from uBITX" was attempted, returned this:? "[8:30 PM] Error Receive Length = 0/1027".
OTOH,? uBITX Manager did report success when told to upload the .btx backup file I created earlier (Load from File).? BUT - it again failed the "Read from uBITX" command.? Display never changed.? I get the impression the Arduino died...

Ready to take it outside and shoot it? ;) , but probably will put this project away for now.? A big question is, if a version 5 is released to fix some of the original issues like spur/harmonic levels, do I try again ????????

Better luck to everyone else!
73,? Woody?? KZ4AK

I have finally got my "Franken" uBitx to the point where it is receiving
signals; at least from my HP 8642A signal generator. But, there is
something
strange going on, and I am wondering if anyone else has seen the same
strangeness.

When I originally ran the si5351 calibration program, everything looked
great and I have up with a correction number of 15380. The 10 MHz was
measured by my HP 53131A counter referenced to a GPSDO.

Fast forward to a little more testing, and I discovered signals I had been
receiving were no longer where they once were.

Running the calibration program again, with the same Adafruit Si5351 board,
I arrived at a correction number of 14210.

So my question is: has anyone else seen the same Si5351 use different
correction factors to generate the same output frequency?

Really scratching my head over this one.

73

- Mark N1VQW

I hope your coming wattmeter will come properly set with reliable readings at least for CW keydown or average SSB power. It seems there are many cases they sell stuff non properly set. When I got the licence I too had bought a new swr-power which was showing misleading values. Luckily enough at the local ham radio club my elmers not only found the problem but in few minutes set it right (three trimmers....). I have to say my wattmeter was neither Chinese nor Indian (!!!!) but made in Japan... A reliable and cheap way to measure the power (not the swr) on CW keydown is the RF detector as the one sold by Hendricks.

Il 02/nov/2018 03:11, "Joe Puma" <kd2nfc@...> ha scritto:

Ok? got it.
> On Nov 1, 2018, at 4:10 PM, Clark Martin <kk6isp@...> wrote:
>
> I should have said you need to subtract the Tx idle current instead of the Rx idle current.
>
> Sent from an iPhone, don't ask whose.
>
>> On Nov 1, 2018, at 12:13 PM, Clark Martin <kk6isp@...> wrote:
>>
>> You also need to subtract the Tx idle current.? You can find this by keying up the mic with no audio input.? This current is mainly the bias current in the finals but also the relays and some other things.? The Tx idle current will vary with band.
>>
>>
>>> On Nov 1, 2018, at 11:07 AM, Joe Puma <kd2nfc@...> wrote:
>>>
>>> Hey guys,
>>>
>>> I will probably have a watt meter in the coming weeks but I still haven’t measured my power out on the uBitx. So with a dummy load hooked up I took some power measurements with my DMM. I am not sure if this is a good way to tell power output but here are some measurements.
>>>
>>>
>>> Voltage is 12.67 Radio idle and 12.45 while Tx’ing. not sure which one matters most when calculating power or if the difference is negligible but I calculated wattage from the 12.45v
>>>
>>> band? ? ? ? current? ? ? ? watts
>>> 80? ? ? ? ? ? 2.18? ? ? ? ? ? 27.14
>>> 60? ? ? ? ? ? 1.50? ? ? ? ? ? 18.67
>>> 40? ? ? ? ? ? 1.97? ? ? ? ? ? 24.52
>>> 30? ? ? ? ? ? 1.42? ? ? ? ? ? 17.67
>>> 20? ? ? ? ? ? 1.65? ? ? ? ? ? 20.54
>>> 17? ? ? ? ? ? 1.22? ? ? ? ? ? 15.18
>>> 15? ? ? ? ? ? 1.15? ? ? ? ? ? 14.31
>>> 10? ? ? ? ? ? 1.0? ? ? ? ? ? 12.45
>>>
>>> If I take into consideration the .33a for radio idle (4w) is my RF wattage 4w less then my measurements.
>>
>> Clark Martin
>> KK6ISP
>> Another Designated Engineer on the Information Super Railway.
>>
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