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The advice given at this thread works well to get you back on track if your calibration gets knocked out of wack:
/g/BITX20/message/47750

Dan, W2DLC

inline wattmeter? set as needed to keep from overheating.? PSK31 about 1/3 to 1/4 power.
It will be different for different modes and bands.

Many of my radios don't have ALC to watch so you need to know whats going out.

Allison

With the 86mhz filter you need 98mhz and 74mhz for downconversion to 12mhz.
Thn you need LO to signal, with 86mhz filter maybe (have to run a spur table)
83 down to 55mhz? (LO below IF) will work.? Could work on first glance.

Or very simple three filters for 15/12/10 and switching to insert them in before?
the power amp, it can be done with diode as the levels are well below -10dbm
at that point.? ?Add a 10-12db mmic after that with max power out of 10dbm
and push for lower gain in the whole strip.? ?To select the filters we can use?
existing lines TXB and TXC mean thing until TXA is switched as there are
unused states there.?

For band pass selection we have the existing Low pass filter selectors.

TXA? ? TXB? ? TXC
---------------------------------------
0? ? ? ? ? 0? ? ? ? ? ?0? ? ? 30mhz LPF
1? ? ? ? ? 0? ? ? ? ? ?0? ? ?20-17m LPF
1? ? ? ? ? 1? ? ? ? ? ?0? ? ?40-30M LPF
1? ? ? ? ? 1? ? ? ? ? ?1? ? ?80-60M LPF

?Unused states 011 and 001
For for over 21mhz we have two control lines to select filters with TXB and TXC.
TXA =0 means the 20-30mhz selection TXA=1 means below 20mhz selection
or no additional band pass filters required.
So we can select up to 4 filters(two lines encoded) as needed with just a bit
more program logic.? Using the two lines raw then? and two of three (15, 12
and 10) can be selected.

And 6M, sure redesign the entire power chain everything, except for the irf510.
What is it about stuffing 7 pounds in a 5 pound box???

Allison

Sorry for my question if answered already.
I want to know whether ubitx factory firmware support cat control or i need to install others.

Howard,? I called CQ a couple of times after I talked to Stan, then went to bed.?
Dan, W2DLC

For the very low bands and narrow bandwidths I'd thing simpler radios would do well..


Allison

The more I play with the Nextion ?Suite and get use to it the more I like it. As with the button you just click on button and it is done for you, it has a field for you to put in what you want it to do and you are through. This is the easiest for me to do I don't have the coding ?ability that alot of you guys have so I have to go simple. I don't ?need a large LCD because I want to keep my total rig size down for my uses. I have a 7 inch display on a pi that I got from buydisplay, it works but it was no plug and play and by time I was through I was wishing I had of spent $10 more and got the one that was plug and play. I do feel that their are a lot of these displays out their that can do the job and from what I see their are people here on this site that can do it. The more interest we have in doing this the more envolvement we will have in making this work. I am only using a 3.2 screen for what I need if I need bigger then for me I will consider ?buying a IC7300 ?that has the internals to back up the large view. This is just me and I am by no means trying ?to offend ?anyone.
73's ?kn4ud ?
--
Allen ?Merrell

That is good news, I would look at one of the trifilar interstage transformer being shorted.
I mentioned the numbers earlier.

If the transformers are fine then a dry solder in the RX chain or filter would be the culprit.
A DC voltage check on RX BiDi amps would confirm they are OK or not.
A general check to know if a 3904 is blown (very unlikely) is voltage across Base and emitter.
It should be around 0.6-0.7v.
If you get no voltage then check if that stage is getting Rx 12v. Also unlikely in this case.

I will bet on the trifilars as for now!

Raj

Thanks Raj, I will look on that! But now a little more info: I looked up a very strong broadcast station at 13.580 on my little transistor radio (with a small telescopic antenna) and I could hear on it my ubitx! But very weak..
Could it be an idea to order some 2N3904 and start replacing?
H?kan

I think OTOH that this problem is not due to your accidental interchange.

CW is generated by the first mixer stage so it is something in the 2nd stage or
later. Check BFO frequency and IF stage (2nd) for any bad solder and specially
check the T3-T7. Shake them gently and see if any change.

Raj

Hakan,

Got it! the only severe damage could have been cause by PIN 3 +5v and 4 Gnd.. now this would have
connected to volume ground and center variable pin. If the volume as at minimum as it would be
when you switch on then the volume control would be damaged.

5V would have gone through the volume ctrl to PTT line which would have sustained the voltage.
This would have happened if the center pin of volume control went op.

Raj

Raj, I did not shift the pins - I put the Raduino connector on the ubitx board and vice versa!
And more: the CW part works with RF out. (Have not tested the SSB part yet.)
And when I connect the antenna the noice level increases. But I hear no signals what so ever, just birdies and background noise.
H?kan

When I inserted the Raduino one pin to the left the raduino was toast!
The damage depends how many pins did you shift left or right.. one of
the pins has 12v and that would fry the Si chip or the nano.

Raj

Why not keeping just one frequency like, 7177 which is common to both sides of the Atlantic and the other oceans?

John,

I use an Arduino Nano AD9850 external vfo? with my Corsair II, that uses a free turning optical encoder and the Corsair digital display.

Currently working on another version with a 20 x 4 lcd display, 2 memories, changeable step sizes and RIT.
Also has up/down band buttons?so the lcd shows the same frequency as the Corsair, when on normal sideband.

My objective was have a free spinning tuning knob and to avoid mechanical pto wear problems in the rig and external vfo.

Using the Raduino with cat is certainly in the realms of possibility but you would?probably need to add a buffer amp and?certainly a low pass filter.

73 Bob GM4CID

What does local mean? A nearby station on medium wave, a station just above the 40 meters band or an FM broadcast?

Hi,
I have successfully completed the microbitx construction. when I calibrate I could hear the strong signals from the local broadcasting station. I could not avoid it,though I hear the ham nets in 7.050 and 7.12345etc. I tried several times to calibrate it but in vain. any solution for this.? 73 VU3JYT