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Sorry not deviation meant amplitude. 1khz signal 50% amplitude.


I also did a zero beat against a 7.150MHZ signal 1khz using my signal generator to transmit and then listened on my commercial radio and ubitx to sync the 1khz sound.? BFO sounds perfect at the default.? ?I also noticed through the earphones I could hear as little as 20-30mv signal via ubitx I wasn't able to easily hear on the speaker of my yaesu.??

Even still I can't pull in intelligible ssb conversations on the ubits that my yaesu ft-991 can easily hear even using the same antenna 40/20m fan dipole.

Hi Dave,

There is some FM allowed on 10 meters, higher than 29 MHz, and I wondered if you had yours working to at least receive FM. The xtal filter might make that impractical (I gave it some thought). Mine is about 1700 Hz wide. That is tight for SSB but with fine tuning steps I can get them right in. More QRM gets blocked. I have the CEC software and do my hunting with 50 or 100 cycle steps and then go to 10 Hz tuning steps to listen - fine tuning.

I always use cans for serious listening and QSOs. We can hear right down into the noise with cans and not with speakers. Hi-Z cans help reduce the "sonics", the high frequency background noise or hiss. I have some of those, too. If you get the chance, give a set of the Hi-Z cans a try and switch back and forth between the Hi-Fi cans and the Hi-Z. They also help on SSB or AM but not as much for music. We are not supposed to be sending music, at least not in the USA. Don't use the Hi-Z with your stereo set:)

I wonder if your BFO level is maybe a little soft. Or the incoming signals are little strong. A strong signal just outside the xtal passband can be hurtful. Try reducing the incoming signals (it's easier than increasing the BFO). Use a step attenuator. A couple of ten decibel steps ahead of the receiver input is good enough and you won't need lab grade attenuators:) Attenuators make an enormous difference listening to low level signals in *all* of my radios. Increasing the attenuation (and reducing the signal levels) seems counterintuitive when we listen for very weak signals. But many's the time cranking in 10 decibels of attenuation makes very weak signals audible right next to a blowtorch. Sometimes an additional 10 decibels is even better. And sometimes not. Some times QRM just plain puts us out of the game.

Good luck and 73,

Bill KU8H

--
bark less - wag more

Interesting ubitx can receive FM ?? Could use better headphones though still would expect the sound quality to better.? Powerful signals like my nearby commercial radio come in a lot better, intelligible but a little off but almost any other signal doesn't come in very intelligible at all.

I noticed today something else interesting.
Even though I can get the same receive 1khz zone on both my yaesu and ubitx on the same frequency.? When I transmit from ubitx to my nearby rig the Yaesu picked it up faintly until I tuned 2-3khz down from the 7.150MHZ transmit frequency on the ubitx.? I could hear on the yaesu better the ubitx transmitted audio with the yaesu tuned around 7.147-7.148 or so.

Not sure if that has any correlation to receive since I could zero beat on the right frequency with the yaesu and ubitx on receive...?

Receive frequency seems perfect though so if I change it that would impact my receive frequency also right?? BFO sounds spot on for the receive.

Tried that it's hard to actually even record my volume is so soft to start out with.? But from what I can tell it's seems to be tuned about correct.

I wonder if there is a bug in the software to make the transmit signal wrong.? I will debug it when I get a chance.? Either way though I should be able to compensate for transmit frequency being off via software I believe.

Given how soft my volume is and it doesn't seem to drive the speaker... I might try that RF pre-amp and also thinking about adding an additional audio amplifier board to see if that helps at all.

Dave,

FWIW - My mod of bypassing the audio output section entirely and using a 741 opamp followed by a audio power amp IC gave strong audio...? It was still somewhat RF deaf but the mmic amp / attenuator fixed that too.
Woody

Thanks Ted.? Interesting didn't think about using a board like that, it is an interesting project to try.

For just audio gain I was thinking about one of these??though doesn't have AGC which would still need to be added.

Thanks Woody I'm looking at parts.

Is that MAR3 chip?

Dave,
About all I can say about your link is the part number looks correct and it is relatively expensive.? Not much supporting info though...
I ordered mine directly from MiniCircuits.? The MAR-3+ is the standard chip, the MAR-3SM+ is the low noise variety.?? They were only $1.40 each, but the down side is there is a minimum order of 20.


Woody

Thanks for the link Woody.? I'm looking forward to betting some more amplification in this ubitx, hopefully it helps.