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There's a lot more going on here than just replacing R13 with a 1n4007. We need to send a current through the 1n4007 from a control circuit, the more current through the 1n4007 the lower its

RE: Allison recommends using a 1n4007 as a pin diode to set the gain in one (or both) of the bidi IF amps, many of us have a 1n4007 in the junk box: /g/BITX20/message/45984 Jerry,

Hi Bret, I got a result, not perfect but It will do for what I want. I adjusted up RV1, a 100ohm trim pot which is before the final chain. It didn't solve the problem of why the difference between

Chuck, Check to see if you have the heat sinks on the finals touching the case. That will blow them. 73 Mike KF6KXG

How big are the spurs at 12Mhz? Transmitting on 20m I could barely see that on my Softrock receiver (which grounds on TX) and a lot less than the fundamental, seems, I would say at least - 50db. The

Thanks will check.? I was thinking about that before and I tried a random cap I had around but didn't seem to make a difference maybe have to try a different one.

Chuck,? there are cases where people have wanted a new Raduino and hfsignals has allegedly sold one of those , independently of other hardware (via an email enquiry to the gmail.com? letterbox ).?

Thanks to all who responded, I was checking solder points with a meter... voltage ect and it blinked and blew a fuse( 2A)? ? ?now i get no hiss out of the speaker.... after replacing the

Basis of? above? rabbit out of the hat statement Drive power? in this case 25 mW =? 10 Wout? x Alog? ( - 26/10)

Reviewing this tale of woe, I find no mention of initial bias. It's a common failing that people will 'zero' the pots before power-on, and *before* RTFM! Reading that fine manual will reveal the bias

Hi Rod,? Did you ever get your low power issue resolved? I have finally gotten around to getting my UBITX V3 board done and on the air and I find the same issue as you have described here on this

Check (with an ohm-meter) for resistance to ground on generator ...Likely it has 50 ohm to ground ..If you hook that directly across the base of the transistor, you've just mucked up the bias on that

Yes, points connected to volume control are in parallel with existing wiring.? The relay and regulator are new, not the existing uBITX ones.?? Here is a photo of the mod that I made for mine.

Interesting thanks that is a good map to work through will try to trace. I noticed something interesting maybe it's expected trying to understand why though.? If I input a low signa from generatorl

There are pros and cons to each approach, which is why JackAl has both RF and audio AGC. Indeed, the AGC section takes up a good portion of the JackAl's nanoacres. BTW, we just received the assembled

There have been dozens of threads in this forum about adding AGC to the Bitx40 and uBitx. Most get hacked in (both detection and attenuation) after the rx audio preamp, to prevent ear damage on a

I had microphony that turned out to be coming from a poor fitting 8 pin audio cable.

I could only find link to complete kit, is their a link to just the parts ie: main board as it comes in a kit ? I did send an email a couple of weeks back to hfsignals but have heard nothing back...

Wow clever adjusting the bias on the pin diode. I assume that the points connected to the volume control are added in parallel to existing wiring? Where do a1 b1 a2 b2 c1 and c2 go? Is that the

Ok Bill, I think that solution may be temporary but it does not end with the problem. I have to continue investigating where the microfonics arises and how to solve it, because this effect is a