What's in the box Mike? A pulse generator for NB noise blanker adjustments. Schematic and demo.

[@bobblum5973]

Schematic Revision 1: Connect pin 7 of CD4093 (Vss) to ground aka battery minus. (Yes, we all miss the little things... :) ) Mike, thank you for all the tips & tricks you send out to help teach people. I haven't touched CB gear in decades, but was around in the very early '70s for tube-type rigs, pre-23 channel solid state ones (like a Realistic TRC-9A three-channel mobile). When I went to a tech school for electronics, the old ex-military instructors called me up to the chalkboard to explain how digital Phase Locked Loop synthesizers worked. I think if I'd kept doing it my bench would look like yours. So from one old electron-pusher to another, keep up the good work!

[@mikesradiorepair]

Thanks for pointing that out. I completely missed that. I added a update to the description under the video.

[@bobblum5973]

@@mikesradiorepair - Good; inexperienced people might build the circuit and not catch that, wondering why it didn't work. But then that's how we learn! I've actually seen a board run a bit then randomly quit, then found it was due to the power pin on the CMOS microprocessor being bent under and not being connected. The CPU was so low power it could steal enough current from other pins to work up to the point where too many pins went low and it conked out. I've also seen someone put a PL-259 on RG-58 coax without using the UG-175 adapter. They unbraided the shield, soldered it into the center pin of the PL-259, and soldered the center conductor to the shell. I wished I could have taken a picture of it, I saw it and I could hardly believe someone could actually wire a coax connector backwards!?!

[@mikesradiorepair]

LOL, now that would be something to see. I have seen a lot but I have never seen a coax connector wired backwards.

[@TheBrforsberg]

Thanks for posting this comment. I just finished building MIke's Noise Blanker generator and found this out as well.

[@bobblum5973]

@@TheBrforsberg Glad to have helped; thanks go to Mike for the original design!

[@Captain1717Q]

Mike my brother come back we're hurting out here in CB and radio repair world you the man come on Mike.....👍👍👍👍👍👍👍

[@zooyawk4526]

Very impressive Mike. It certainly works and very well for what it's intended for. And the cost to build it certainly can't be beat. Big thumbs up on that little box.

[@troydavidson5661]

very cool to see and learn this about the noise blanker, I don't repair radios but this would keep the old lady out of the shack !

[@TheRadioShop]

Nice project Mike. Really great for checking out the NB on radios.

[@PapasDino]

My NB tester was built eons ago with a 555 chip; I like yours and gonna make one just to say I've got a "Mike NB Tester"! ;-)

[@MrCaveman8]

This is really cool, thanks for the video !

[@km6hvu622]

That is cool! It sounds like the alternator noise when the red light turns green and the engine RPM's increases.

[@allthegearnoidea6752]

I was definitely going to ask. Thanks for showing us the magic. It reminds me of a time delay reflectometer circuit i built. These are an ideal projects for dead bug style construction. Regards Chris

[@northbetrue]

AllTheGearNoIdea hey what’s dead bug style? It’s a cool phrase! No idea what it means heh

[@allthegearnoidea6752]

KC1ANR Boston USA John Sorry for not replying I did not see your comments. Dead bug is when you build you circuit on a copper clad board but all the components have the legs sticking up in the air. ICs look like a dead bug when upside down

[@robschlotterbeck2566]

Thank you mike. You are the man! I’ve been excited and waiting on this one! Sorry to ask for the information on how to make one.

[@marktiger4613]

I am new into learning repair part of electronic almost got my kids out of the house I know you don't work for pace but they should hire you I had a old soldering iron that I got at a yard sale for a quarter it took me a while but I picked up a pace mpt system cheap I figured if I was going to buy I would try to get what you say is the best plus it's made in the USA I always give you thumbs up and look forward for new videos

[@marktiger4613]

Also thanks for your service

[@rpcomms1]

Now you done it Mike,put foot right in it lol Good vid Mike Rob

[@martyaussie4538]

Great project, but i'm concerned about the 3 NAND output pins on the 4094 being directly tied to each other, shouldn't we use 3 diodes (or even 3 small caps?) to couple the 3 signals without causing either output pin to blow the other output pin(s) ???

[@bobblum5973]

I'd need to look at how it's wired (don't have time right now) but if the outputs of all three should always be the same state and since this is a CMOS device I think it should be fine. I've seen two TTL gate outputs tied together as what's called a wired-OR or a wired-AND gate, too.

[@RFFrancisrfdx-member]

Hi, Mike. the other end of the 1m resistor should go to ground also?

[@DAVIDGREGORYKERR]

I wonder why the Transceiver didn't go with DSP processing and use an Adaptive Noise Filter and thereby remove the noise from the audio, CVSD ADCs will be used to drive both inputs and a CVSD DAC will be used on the output to recover the cleaned audio, the Algorithm will be the LMS, the noise source will be a noise generator.

[@user-su5sq5ib3i]

I wonder if you put an inductor before the isolation cap on teh output it may cut down on the extra hiss as there is probably 5 to 9 VDC floating right at the cap. PS I wish you would make some more videos here where the heck are ya huh???

[@rickkephart5690]

I need to learn how to do this. How to read a schematic and understand what it does and why.

[@marianmarian8945]

Hello Mike ! Could I use an IC 555 generator instead of CD4093?

[@KJ4CRH]

Is someone tickling you in theses videos??.....I'm just curious 🤔

[@samuelmorrlson9005]

Digikey 438-1160- ND twin industries. Nice find.

[@johncundiss9098]

Question. 1.2 V peak to peak? That cause it unterminated?

[@Jeff-sc1df]

Nice job! Of course you know folks are going to ask you to make them one. Haha........like me......

[@misterhat5823]

One could whip out a PCB in less than an hour and have a Chinese PCB maker make them for less than a $ each. Mike might be able to start a second business.

[@cw5059]

Mike, did you at one time teach?

[@kevintinney6964]

Can you tell me what model cobra radio was the base mobile it was a very large mobile with a biotin 110 posse supply and do you where I might find 1?

[@mikesradiorepair]

Cobra sold numerous different base stations over the decades. Some of the more popular ones were the 89XLR, 139XLR, 142GTL, 1000GTL, 2000GTL. Where can you find one, anywhere used electronics are sold. Public auctions, online auctions, pawn shops, thrift stores, yard sales, HAMFEST shows/swap meets, etc.

[@misterhat5823]

Wait... How can that work? Having the diode in series with that output cap won't allow the cap to discharge and you'll get no output. (Except for a tiny amount as the diode has a parasitic capacitance.) To get positive pulses only, there should be a resistor to ground at the junction of the diode and capacitor.

[@defaultuser000]

That's not what we're after here. If you look at his scope output there are still both positive and negative pulses. This setup just allows for a very short duration pulse, with about a 1ns rise time. You get both positive and negative pulses. The output pulses occur on the rising and falling edges of the NAND gate outputs. You could get something similar using a tiny capacitor (1pF or so) terminated into a resistor which would only allow the high frequency content of the fast rising edge to get through. The square wave output of the gates is rather slow, but the edges have very high frequency harmonic content, and that's all we want here. Honestly, the diode seems to be working more as a tiny capacitor in series with the cap before it to provide the HPF effect to get the pulse content.

[@misterhat5823]

@@defaultuser000 In other words, there's no need for a diode. The cap could just be changed to a few picofarads.

[@defaultuser000]

@@misterhat5823 Yes, you can replace the series cap/diode combination with a 1pF capacitor feeding the 100k output pot and you get the same type of pulse train at the output. It's just an RC high-pass filter you're making with the cap and output potentiometer. It's filtering out all of the lower frequency content of the square wave and leaving only the high frequency content of the rising and falling edges. It works great for testing noise blankers as Mike demonstrates. It's so simple it's genius.

[@TheLonesometoad]

When ya gonna make more vids, and when ya gonna answer texts and emails. I needed something done about 6 months ago but had to go elsewhere as you wouldn't respond.

[@KJ4CRH]

He was getting TICKLING done to his toes

[@مازنجزائري-ص2ع]

شكرا لهذا الشرح اتمنا ان يكون مترجم الى اللغه العربيه

[@Dazzwidd]

that thing needs a bandpass filter and a big amplifier after it 😂

[@kevintinney6964]

I ment built in powers supply

[@stevepotts2116]

IF YOU, NEED A, 9V,CONECTOR,,TAKE, APART, 9,VOLT,,,BATTERY AND YOU HAVE A, CONNECTOR..,,..