The (not really) official electronics workbench thread

Mr_Roboto

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Saw this video on reverse input voltage protection, chuckled a bit and thought the info was really good. I'm going to use it with the Lemons instead of a diode if I ever get er running again.



I also ordered an ATU100 antenna tuner kit. I want a ubitx haven't pulled the trigger yet though. I want to combine that with a homebrew antenna, end product would probably be 250-300 for a HF station that's highly portable.
 

Mr_Roboto

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So, I purchased a ubitx yesterday. This could be interesting. It's an older V3 but I wanted something without the bigger LCD display due to the power demands. My goal is to make it where I have a custom 3D printed case where I can do digital modes on ham radio (the plan is to integrate an older mobile phone to handle that functionality using DroidPSK and DroidRTTY) so that I wind up with an ultra light setup for this. The initial goal would be something like 7-8 lbs I Think for a radio, battery pack, tuner, (NIMH or Lion) some form of charging, an antenna and possibly the mobile device. The metal cased kit is 2.5lbs so I think I can 3D print that weight down since the shielding seems really minimal.

I know I've got a series of mods I need to make to this. It's very much a hacker's radio so we'll see how that works out.

I'm thinking about one of these as well so I can be sure I don't have spurious transmissions. They seem to have a pretty good review based on forums I've read through.

https://www.ebay.com/itm/293856994838?_trkparms=ispr=1&hash=item446b3de616:g:Cv4AAOSwQ3Ffv3aM&amdata=enc:AQAFAAACgBaobrjLl8XobRIiIML1V4Imu%2Fn%2BzU5L90Z278x5ickkvjzWOStkxwnlDuxSI1PVVtN0K0d2oOjU1qpGehMA9Twkza4jyKfeboFe2n165sn94fCKnLcgrjs4fl3fehqMd4ToJePC3Rij0upz9f5W7K0MMTPyeAkD%2FhOuUU0mTqUweTi6WZYt56IJvGRbQOo6FJShFItUzhcNKBMlcvtGCk1ZZm1xh97YNsC99DGgJoMbh3m9eVSqlQWWb4NaMO39fAQkElOxjr2a0uZRQp7%2BSQwkXQLfNA77zew9N9U4KQR7fh4P5owklHFOaWQ7UfxUGP8ziQqNdFcm2AIYnRx5%2Bm7%2BXxCOG7RPrDwbOIbVARlWjeSoTL1VtgvqjhsbRb2H0Ydk7chkUFobjGb1vrbihX0Jsi7RKx1Ls2kmlmG%2FhAPpDLSvZ2B%2FWkOLGYbj64ktXim7EsBloHxJ45NCjdPBHgD3myBnmf2q3NNW51TYWLTCCIVlJVDc041gtEhwV0hGeZM5xDctW9Vco2pkMd%2F0M%2BRrmxDzSEomkfTfTcN5OFmSFgyuoj9242qxYTl%2BEEBvLfXcPLYgyg5NhHi8RSMgr88wqcAYpQyGmzfR%2BcGCH62SSpXGxF8Z53erdjbEkKPoGXzTTQTeRqb2N3Khbp3yY9o0yoIf%2FomJu57l88NWJ4zw3NUDTqfpyJIEcQyMfts%2B%2BzSINsXf71S9uZPzxgoSWTdo4hbBolR8Bs9837CPw3Q5BCpToeihhwQuUgVXJMrY0wtvZpAjZhLXgGiUwzoFWC1DO5smpIc4Bv95r9DsP1WD8WIXwCwAW%2FxM79%2B5TMdqdi5Ib34sccMioi5GEBqkq%2F0%3D|cksum:293856994838be1b87d0cb4b4b6098f671be10a873d3|ampid:pL_CLK|clp:2334524
 

Bigturbonotch

WAIT AND SEE
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Our testing hardware for cable harnesses.



89CDF32B-83E4-497A-982B-388463A15BFE.jpg
 
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Mr_Roboto

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Right now anything tech related is a hobby, but I would rather work with hardware than software when I do.

There is no reason not to do both. There are some super cool pcbs out there that ise code. I rolled my eyes at the Arduino stuff but the capability is awesome.

I will say if you want to go true old school we could talk tube gear. I love tube gear.
 

Mr_Roboto

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The ubitx showed up today. Tracking said Tuesday I thought so no complaints about the usps here.

weight less rf and power connectors was just over 12oz less the board. That is really good for my weight desires for this. I need to 3d print a case but want the tuner I am integrating to show up first.

I need to start seeing about that spectrum analyzer and parts.

IMG_20210529_174048009.jpg
 

Mr_Roboto

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fixed the wiring the po had fucked up, dug out a power brick for a monitor, tested, calibrated, flashed the firmware, tested and calibrated some more, put an antenna in the yard, hooked stuff up, bought an android app and received psk31 on 20m from nc, tx and Venezuela. The receiver in this met spec as documented for sensitivity using my signal generator I am impressed. The transmitter needs a decent bit of work before even getting close to being ready to use. I don't even have a mic hooked up.

IMG_20210530_175210641_HDR.jpg
 

Ron Vogel

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It’s based on a brown fender princeton. I replaced the tremolo circuit with a deluxe style phase inverter. That way I can get power tube distortion. Also added an extra filtering section for the preamp section

used this amp for all the electric guitar work here:
 

Mr_Roboto

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https://www.ebay.com/itm/332189331793?hash=item4d5806f151:g:imAAAOSwY3BZJVl~

This attached with some sort of massive heat sink would make for an awesome dummy load for radio work. I ordered a few so we'll see. I'd previously built something out of some 250 ohm 50W resistors but they are wire wound so that's not going to work at all. I'll find something to do with them eventually (more than likely I'll make a big resistor to test power supplies of some kind) but not yet.
 

Mr_Roboto

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I have never aligned a radio before. My inlaw asked me to look over his Philco. The audio out tubes were really sketchy looking (mixed pair) so I stuck in a pair of mine. Much better but even so I needed -28dbm on the signal generator to hear a tone. Basically a deaf radio. I did the alignment on it and am at about -50dbm now. Every 3db is a doubling of power basically so that means the radio is over 128 times more sensitive.

I think the rf tube is shit so I ordered another along with the audio tubes to replace his. I haven't really heard much on shortwave but I think that the new rf tube may help that and trying at night when the lower frequencies open up. I have heard a lot of the Japanese short wave stations shut down but am still hoping a few exist to hear.

Otherwise I just replaced the power cord on this radio. 1938 vintage, built to last.IMG_20210609_173148187.jpgIMG_20210609_173135790.jpg
 

Ron Vogel

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I have never aligned a radio before. My inlaw asked me to look over his Philco. The audii out tubes were really sketchy looking (mixed pair) so I stuck in a pair of mine. Much better but even so I needed -28dbm on the signal generator to hear a tone. Basically a deaf radio. I did the alignment on it and am at about -50dbm now. Every 3db is a doubling of power basically so that means the radio is over 128 times more sensitive.

I think the rf tube is shit so I ordered another along with the audio tubes to replace his. I haven't really heard much on shortwave but I think that the new rf tube may help that and trying at night when the lower frequencies open up. I have heard a lot of the Japanese short wave stations shut down but am still hoping a few exist to hear.

Otherwise I just replaced the power cord on this radio. 1938 vintage, built to last.View attachment 91531View attachment 91532
I have a tube tester if you need to check. It doesn’t do some of the old tubes, but just about anything after the 40’s/50s though.

3E2B9445-2C35-4533-BD5B-5A8643EAF7BC.jpeg
 

Mr_Roboto

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We'll see how the new ones do.

I'm guessing the "good ones" are probably audio preamps like 6DJ8s and 12AX7s and power tubes like 6L6es? You should see the stash of 7868s and 7591As I have laying around. I have a Fisher (I remember it as a) KX200 that needs to get put back together as well. I got it for parts since it was super rough they just seem too damn expensive now to do that to.

I ordered up a pair of matched 6F6es and 6U7G for the RF amp. That's a Pentagrid converter so it's a bit of an intricate tube and I just didn't have anything stashed. I also ordered a stack of 6AG7s since shipping was free and they're good for ham radio stuff like oscillators. I swapped the 6F6es after the alignment but considering it's strictly audio tubes I have no qualms about it throwing the alignment off.
 

Ron Vogel

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7591’s are the shit, I wish I still had some. I only have 6k6, 6v6, and vt107 for power tubes since that’s what I like to use in guitar amps. Power tubes are fast sellers, so if I ever run across vintage 6l6 or kt’s etc I know I can get top dollar and flip them.

I have some nice late 50’s black plate RCA preamp tubes though I could never sell since it’s so rare to find good ones anymore…and they last forever.
 

bikrboy128

Some say.....
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Not sure of I am that serious, but what brand/model may I ask?



It's a little overkill for what I use it for, but I enjoy working on electronics and having everything on one station is great. The vacuum desoldering gun makes component swapping cake. Also both hot air and de/soldering temps are adjustable with multiple saved presets.
 

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