Got my BITX-40 this evening.? Built it up and got it working well.? I had a inductor with a broken wire, but after soldering it back on the board, all works great.? First contact was IK8ETA, then a Florida station.? Good stuff on 7W!

Look forward to getting this thing boxed up and looking better!

Jason

N3YUG

That figure could vary widely depending on how your ohmmeter is built and the charge state of the battery in it.

Jerry, KE7ER

Hey gang,

That would be me that set up a yahoo group for pnw builders.

I don't know how or why I became the focus of email flow for builders in the Radio Club of Tacoma and the pQRP group but it very quickly got way out of hand. People were left off the email list, adding them and getting everyone to use the larger list was impossible, and my time is better spent playing with my BITX40. My only recourse was to centralize the listees and encourage all to seek out the other groups that traded BITX40 info. So I started a yahoo group pnwBITX40Builders. Where it goes is up to the members... I guess.

I just don't have time for it.

73,

PJH, N7PXY

Did you check the mic amp output with a scope after removing the transformer? ?

> ?I have removed the trifilar transforme to make sure there were no shorts.?

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Well, no vote for a separate group for the smd version from me. Virtually anything applicable to the through hole version is potentially applicable to the smd version, including expanding band cover etc. As time goes on, fewer smd rigs are likely to remain the same as they left the hfsigs base in VU land, as new and better mods are identified.

Why dilute the knowledge base by splitting the group?

Bill, VK7MX

Hi all !

Does anybody knows if the Electronic store "Indo Ware" still is in business ???

I have tried to mail them several times with no succés.

73 de sm6mpa/Hasse

That's a weird one all right. ?I can't tell you where the problem is, but I could tell you how I'd go about looking for it.

If the diodes don't look fried, I doubt going to the dual diode package is the difference in readings. ?Maybe short out the 100 ohm pot, see if that makes the ohmmeter readings on the new rig more closely agree with the old (though I'm not totally convinced that's possible). ?Could also check the data sheet on the dual diode (whatever it is) and compare with the old 1N4148's, perhaps the knee in the V-I curve is a bit different, and your ohmmeter is testing with a voltage there that is right at the knee. ?Put a little heat on the diodes of each rig in turn, see if that makes for vast changes in ohmmeter readings.

There's three networks involved here, the modulator, the mic amp, and the rx audio amp. ?Maybe pull C112 and C126 on both rigs to isolate the three. ?Now see if the mic amp output is comparable, measuring AC voltage at the collector of Q12. ? You could also compare the 12mhz AC at the Q6 collector when injecting DC into pins 2,4 of T4 to unbalance the modulator as per post 20933.

Let us know what's going on once you figure this out. ?You got me curious.

Jerry, KE7ER

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groups.io provides for the admin(s) to set up subgroups

I'm happily retired but still get too much email. ?That's why the only email I receive from groups is important owner/admin messages. ?When I'm ready to scan the new traffic, I visit the site with coffee in hand. ?The info I needed to tweak my -40 board came from the experienced folks with -20s - if we split the groups we'd still have to join both to be able to tap both resources.

73,

Andy KG5RKP

Been a ham for 54 Years and engineer professionally. The low power on the new radiuno has me stumped. ? ?I have set up side by side an original bitx40 and the newer radiuno. ?My bitx40 does about 7 ?watts with 12 v. ? ?I am feeding a 1004 Hz sine wave into both units and making measurements into 50 ohm dummy loads. ?All voltages are pretty much in line between the bitx40 and the radiuno. The radiuno only does 1 watt. ? After putting a scope on the radiuno I found some interesting things. ?when transmitting the scope shows that the signal level is very reduded. ?This starts just about at the output of the mic amp Q12 ?and goes up through the trifilar transformer and then on to the input of Q6. ?This level is about 1/3 of what it is in the bitx40. ?I think the low power output is being caused by low drive of the audio signal but I can not seem to locate the issue. ?I have removed the trifilar transforme to make sure there were no shorts.?

There is one change i see between the bitx40 and the radiuno. ? ? Farhan has take out the two diodes and R106 ?and replaced that with a single dual diode (surface mount) ?I removed the dual diode and measured front to back and they are ok.. ? Not much to go wrong in this circuit but I still can not see it. Here is one measurement that I can not quite understand. ? ?At pin 2 of the trifilar transformer T4 ? on the bitx40 (which is working i get resistance measurements of 292k ohm and reversed i get 1.6 Meg ohms. Now on the radiuno i get 14K ohms and reversed i get 81K ohms. ?This is a big difference. I believe it is caused by the new smd dual diode. ? Any ideas?

Tom W5KUB

We need a separate group for the "new" BITX40 SMD board (semi kit). I really don't need to know the fixes to any of the other BITX boards or (kits), and I'm sure that those that have non BITX40 SMD boards don't really want to know the fixes to these new boards.

Yeah, I know what you mean, Ralph. From the various groups I subscribe to, I get about two hundred messages a day. I glance at the subject line and if I'm sure I don't care I hit the delete key. It takes me a entire two minutes to get rid of what I don't want so I can finally read the dozen or so I am interested in. It's especially hard on me because I'm not retired.

73,

Todd K7TFC

Boy. I'm sure glad that I'm retired so I can have the time to keep up with all these posts.? We need a separate group for the "new" BITX40 SMD board (semi kit). I really don't need to know the fixes to any of the other BITX boards or (kits), and I'm sure that those that have non BITX40 SMD boards don't really want to know the fixes to these new boards.? I do like all of the info on the new digi VFO with the BITX 40 SMD. Keep that info coming and I might get a second line of text on the display.

???????????????????????????? 73 Ralph? K1KOB

Tips n Mods.? OK, I've added the voltage table plus a couple of bits.? I think we are close to the end of anymore to add.

Now, in the light of present circumstances, do you want me to upload a copy to the file folder for all to view.? I suggest pdf only it's 571kb in size
--
Rob G4NQX