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Hi!

I would like to know whether the behavior of TX frequency of uBitx at CWL and CWU mode I experienced is normal on CECFW v1.08.

For instance,
When there is the CQ station on?7.0100MHz on my ICOM transceiver, ?uBitx at CWL mode shows 7.0085MHz as RX frequency.
Then I transmit CW carrier on ubitx at the exact same RX frequency of uBitx.
CW carrier is observed not at 7.0100MHz but 7.0085MHz on my ICOM transceiver as RX frequency.

When there is the CQ station on?7.0100MHz on my ICOM transceiver, ?uBitx at CWU mode shows 7.0100MHz as RX frequency.
Then I transmit CW carrier on ubitx at the exact same RX frequency of uBitx.
CW carrier is observed not at 7.0115MHz but 7.0100MHz on my ICOM transceiver as RX frequency.

This means that TX frequency is lower 1.5KHz at CWL mode and higher 1.5KHz at CWU mode than actual frequency.

Your comment would be much appreciated.

Akira,
JJ1EPE

I've a tray full of Intersil TO-3 VN66s here dating from about 1980.
Used some in 5 watt qrp amplifier, used to drive it from the Tx low-level stage of my Atlas 210X for QRP.
de miken,? ?zl1bnb

I too have seen this. I have yet to sort mine out and usually for me happens on an antenna and not the dummy load.

Brad

I was testing into a dummy load and noticed that when I whistled into the mike, or even spoke into it on higher frequencies, would cause the rig to react as if I had pressed the button on the encoder. It showed "Band Select >", and receive stopped. Pressing the encoder twice exited the menu normally. Is this RF getting into the switching transistor the encoder switch trips? How can I prevent this?

Gwen NG3P

That's extremely interesting and informative, and completely contrary to what I'm trying to do. I like the answers about using the pot on the board to lower the output power. Excellent. I'll probably do that.

But my initial problem was that, with a particular battery pack, the rig overdrove my tuner, making it fail to tune. Thankfully non-catastrophically, (i.e., it didn't catch fire) but it still wouldn't tune, and indications were that the power was out of range at the top end.

I realize that most users of radios want to MAXIMIZE output power, and then level it across as many bands as possible, so they have lots of output power in all of the bands they want to use. But I don't want to increase the power. I want to control it. The battery's specs list it at 12v @ 5A. So it has plenty of power and shouldn't limit the transmitter. But that's not my issue. The issue is that with that battery supply, there's TOO MUCH OUTPUT. If I run it from a bench supply, it doesn't do this. If I power the bench supply from the battery, it doesn't do this. I'm charging a battery bank I have with a 12vdc output jack, with a limit of 3A, that I'm going to test to see what IT does.

But I don't WANT to maximize RF out. I want to keep it within the limits of my tuner. I will try not setting a limit on the amperage and just try lowering the voltage, and see what that does, if limiting the amperage causes Bad Things.

Am I not being clear as to my goal in this instance? I'm trying to assemble a portable setup to take into the field for battery operation, but everything needs to play nicely with everything else, and the battery I was trying wouldn't play well with the tuner. I'm also testing to see if the problem might have been with the antenna or with the tuner, by testing different antennas and different tuners, to see if the problem actually exists with the BATTERY and not something else. If I can do it with a different battery pack that doesn't overwhelm the rig, PERFECT. But if that's going to cause bad harmonics or spurs or splattery signal, then that's not so perfect. I want to find the actual CAUSE of the difficulty, not just slap a band-aid on it or treat symptoms, but so far the assumptions I keep hearing are that I'm trying to maximize output, which is not the case. If I wanted to maximize output, I'd be building different sorts of radios, not QRP rigs.

Hello Arv
Plastic cases on power supplies can be sprayed with conducting metal paint on the inside to stop RFI. Just be sure no high voltage parts touch the now metalized surface.
73
--
John VK6JAH

Thanks Allard, I will check that out.
73
--
John VK6JAH

Allison I think he's trying the SDR function of Ian's firmware? That taps off the IF to feed an SDR dongle.?

"I have not lost my mind, its backed up around here somewhere."
--
Lee - N9LO? "I Void Warranties"

?

This amp works very well, with very low distortion.

I have built this amp to verify, it but note the voltage range up to 12v. I found the final pair can get very hot over 12v.? Possibly some re-biasing of the first stage might help that. Or use a BD139/140 pair in the output stage.? I got around 600mW out into 10R resistive load with 240mVrms input which is the max my audio gen will give.

glenn

Arv, you are one smart dude! I love your idea.

Mike N4EEV

From R43 to C32, Is this a uBitx or bitx40?

What mod involves the emitter resistor of q40(R43) and output capacitor(C32) of Q32 in the 12mhz IF???


Allison

Perfectly said and I totally agree.? This is a wonderful group to belong to.
--
Lee - N9LO? "I Void Warranties"

?

Good Afternoon,

It appears all the opinions have faded - I have an update.? I purchased an Amazon LM386 mini amplifier, and? isolated it with a 100mF Electrolytic with the positive side towards the Transistor that is feed off the wiper of the volume pot-? ?And Voila-? the speaker is now loud enough to hear across the room, and it sounds nice,? I have now been able to hear SSB QSO's - however I still need assitance in the calibration technique for a V4 with factory Firmware-? Any tips on how to do it?? ? The little amp is pulling some stray RF and I can hear myself a little through the speaker - but I will work on that in a while...

Please understand the V3 Calibration process is different.
--
Richard
KC7DDW

You can't regulate output "power" by regulating the amount of current
the power supply provides. You can regulate the voltage you apply but
the current drawn is a function of the input power to the amplifier
chain and the amplification of the amplifier chain. The amplifier chain
needs to be operated where the amplifier is linear.

If you operate so that the power supply *never* has to provide 1.5amps
then you would be ok. But if you are depending on the power supply to
regulate the current to 1.5amps regardless of the drive level then you
are likely operating the amplifier chain in a non-linear manner thus
causing IMD products.

At 12v to the mainboard and 15v to the final amplifiers my unit pulls
about 2.2 amps on CW. Of course it pulls about 300ma on receive because
I am using an enhanced Radi2cino with a teensy adapter and a teensy 3.6
cpu.

A 3amp supply wasn't cutting it initially, the output voltage from the
suppy would drop on voice peaks. I went to a 10amp supply and had no
more problems.

try this site: en.wikipedia.org/wiki/Intermodulation
to begin with.

tim ab0wr

On Fri, 29 Jun 2018 20:48:55 -0700
"Gwen Patton" <ardrhi@...> wrote:

Thank you, Tim.

That's certainly a better answer than assuming I want to overdrive
it, or telling me what I already knew, that I needed to regulate it.
I'll check RV1.

I'm still a bit confused about what kind of power to put INTO the
thing, though. 12v at how many amps? My bench supply can put out 3a
easily, but I've been running it at 1.5. I got one suggestion to
regulate the input power...isn't that what I was doing, with the
bench supply? Maybe I need a link to a reference or something,
because the docs aren't very explicit and so far I've gotten 3 wildly
different opinions on it.

at the risk of leaving someone out, I won’t mention anyone specific, but rather speak to the several as a group.?

I want to say a special thanks to you... those that provide great kits at a more than reasonable price, those that supply software, articles and tutorials, but also, the wonderful folks that are willing to dig in with you on a problem and help resolve it. This entire group is owed a vast debt of gratitude by those of us that are able to holler CQ, CQ on 8 watts....

Thank each and every one of you.
72 and God bless you.