Could use some advice on getting in to radio repair.

[JDE]

General-class ham here, licensed for 3 years. I'd say I have an intermediate understanding of RF, electronics, and electrical components. Decent-ish at reading schematics. Many years of tinkering/soldering/etc under my belt in various other hobbies.

I've wanted to take the next step in to being able to diagnose/repair my own radios for some time now, and recently the last guy in town that handled radio/amp diag and repair for us hams in the area moved away so I figured now is as good a time as any to start learning and see if I like it enough to stick with it. Not interested in doing this for money at all, I do IT for a living and that pays the bills. This is just going to be a weekend hobby, and if I'm any good at it, something I can do for the other guys in the local ARES club. Main purpose is that it just plain interests me, and I like working on stuff like this.

I figured I'd get my start on CBs, simpler and cheaper than amateur radios, so I have a few cheap Cobra 29 LTDs on the way from eBay that probably need various repairs or calibrations. I've done a lot of googling, reading forum posts, and watching videos over the last few weeks. I have an email out to Lou Franklin to order his books and a few tune up manuals (no reply yet, he still around and selling books?), and have been browsing what I can from the mirrored cbtricks sites.

On to my question; realistically, how effective can I be at radio diag and repair with basic tools, a dmm, a dummy load, and an swr meter? At what point do I need a spectrum analyzer, signal generator, oscilloscope, etc? Are people still just finding and buying old gear on ebay? It seems anyone I watch on Youtube that does this stuff has all that, and I imagine quite a bit of money invested in to it.

Thanks for your time.

 

[sp5it]

For fault finding dmm, scope, rf probe is enough in most cases. More important is skill and knowledge how to use them and interpret results. You can't learn that from YT.

 

[Handy Andy]

Following @sp5it - lead...

At what point do I need a spectrum analyzer, signal generator, oscilloscope, etc?

The real tools are the radios themselves.

Always good to have several receivers around - ones you can tinker and learn to trust and know the "quirks" they will have with oscillators circuits and receiver noise and the scratchy sounds of old rheostats "tuning in" on signals.

Once you become familiar with your equipment - the SA (Spectrum Analyzer), or the Signal Tracer Or the Oscilloscopes, Many, including myself - find the RECEIVER your most familiar with - is the one that becomes Your major tool you use to help you "align" your other equipment and radios to, it becomes your reference - for your references.

So, to me the Oscilloscope is a good backup to your ears - Spectrum Analysis is more for those whom have to find problems that go beyond typical Oscilloscope and Signal Tracing - and are more for those willing to show their "expertise" if not their pocketbook - to others for their own EGO.

As a Ham operator, you are responsible for your own equipment and emissions from them, so the choices are up to you - but you don't have to sell the Farm to get the latest and greatest.

Sadly, though, the more "fun times" in kit building and self-help/taught "Heath kit" as well as other homebrews - are rare and discretes and support for them are rarer now due to the flood of overseas marketplace crap being dumped onto our shores. Preassembled metal cases with foil backed cardboard to hold SMD components smaller than the many of the letters typed in this message

So, this ties back to original premise of this post.

You are responsible for your own equipment - you now have a license (so to speak) to become its care-giver - you become the one that lives (some of - not all) your life thru the equipment you use to contact others. So, these pieces, then become more than simple tools and equipment - they become a part of you.

 

[TM86]

General-class ham here, licensed for 3 years. I'd say I have an intermediate understanding of RF, electronics, and electrical components. Decent-ish at reading schematics. Many years of tinkering/soldering/etc under my belt in various other hobbies.

I've wanted to take the next step in to being able to diagnose/repair my own radios for some time now, and recently the last guy in town that handled radio/amp diag and repair for us hams in the area moved away so I figured now is as good a time as any to start learning and see if I like it enough to stick with it. Not interested in doing this for money at all, I do IT for a living and that pays the bills. This is just going to be a weekend hobby, and if I'm any good at it, something I can do for the other guys in the local ARES club. Main purpose is that it just plain interests me, and I like working on stuff like this.

I figured I'd get my start on CBs, simpler and cheaper than amateur radios, so I have a few cheap Cobra 29 LTDs on the way from eBay that probably need various repairs or calibrations. I've done a lot of googling, reading forum posts, and watching videos over the last few weeks. I have an email out to Lou Franklin to order his books and a few tune up manuals (no reply yet, he still around and selling books?), and have been browsing what I can from the mirrored cbtricks sites.

On to my question; realistically, how effective can I be at radio diag and repair with basic tools, a dmm, a dummy load, and an swr meter? At what point do I need a spectrum analyzer, signal generator, oscilloscope, etc? Are people still just finding and buying old gear on ebay? It seems anyone I watch on Youtube that does this stuff has all that, and I imagine quite a bit of money invested in to it.

Thanks for your time.

Everybody has to start somewhere. When I first started "fixing" radios all I really had was a soldering iron and an analog VOM. People paid me to swap out their finals and add frequency range. Would have been better if I had known what I was doing.

 

[Handy Andy]

When it comes to SMD though, you might want to look into "hot air" stations for that type of work, far easier than using a soldering iron.

Since technology for this has advanced, some older Air Stations are still viable for most main-plane SMD work, some main reasons for the resale is due to the delicate nature of the microminiaturization and increased complexity of the trace and foil layering designs requiring a more dedicated narrow feeder/blower system with higher tolerance controls.

Else, other aspects of the Oscilloscope is - don't just buy a simple scope, although great for low-cost, what about those other features? Like Frequency Counter and time domain and snapshot multi-trace input and display - might help you in seeing not just RF issues but the CPU communication to and from other devices on the main PCB for SIGNATURE analysis - different from Spectrum Analysis - which is more dedicated to RF signatures than the digital side of the communication process to make it go...

To give you specific models - heck I cannot even begin to state the obvious, there's a lot out there and those offshore accounts are adding more to the eBay junkpile every day. Just find a used one with a counter in it - or review the YT vids and see just how much they fiddle with these display icons and on-the-shelf-and-don't-touch-it-devices - meaning they only use it to show a feature or quirk because they finally figured out enough of the owner's manual to make it do something - not just sit there...which, in their vids - is doing just that...

When you invest money, you have to look at the ability for ROI (Return On Investment) - if it's a labor of love, you don't need to spend much because of mentioning the receiver parts earlier.

You achieve a level of performance using simple tools that many accept as standard - the stuff between the ears interprets. And how good you sound is from your level of experience and the knowledge gleaned - it's done by monitoring the signal thru another receiver - just don't go by using headphones on a tape monitor loop off the receiver itself - Listen to your signal thru another radio you know, as your reference radio - to prove you are ok, the problem is on the other end - not you.

 

[JDE]

Handy Andy - Appreciate the wealth of information! When you say receiver, are you referring to something like a monitoring radio that I know is within calibration? Some of the guys I've watched have a monitoring radio nearby when testing transmit, echo, etc from the radio they're working on.

Sp5it mentioned an RF probe, I'm not familiar with this tool. Looks like something I can get fairly cheap or even build myself and use with a DMM to get a relative reading of RF amplitude. I'll do some reading on that.

All of this is why I wanted to start on CBs from eBay. They're a cheaper, simpler version of my HF rigs and seem like a great way for me to learn about radio circuits and the tools needed to troubleshoot them. Unfortunately, we don't have anyone left in the area to tutor me so I'm relying on the internet for learning resources.

 

[JDE]

Does anyone know if Lou Franklin is still selling his books? I sent him an e-mail 2 days ago and haven't heard back. His website is still live with a 2022 copyright at the bottom of the pages. Everyone seems to love his books and they sound like a good source of information for me getting started on CB diagnosis and repair, so I'd like to order those.

Also, and recommended techs to follow on Youtube? I understand there is always going to be that disconnect between watching versus doing it myself, and I'm more of a hands-on learner anyway, but there is a wealth of information on youtube from the right folks. Lately I've been watching a lot from Mr Carlson's Lab, MikesRadioRepair, etc. Many of the more popular CB repair guys seems to be hit or miss on the quality of their work, and most skip past the meat and potatoes of the troubleshooting and repair processes which is what I'd like to see.

 

[guitar_199]

Handy Andy - Appreciate the wealth of information! When you say receiver, are you referring to something like a monitoring radio that I know is within calibration? Some of the guys I've watched have a monitoring radio nearby when testing transmit, echo, etc from the radio they're working on.

Sp5it mentioned an RF probe, I'm not familiar with this tool. Looks like something I can get fairly cheap or even build myself and use with a DMM to get a relative reading of RF amplitude. I'll do some reading on that.

All of this is why I wanted to start on CBs from eBay. They're a cheaper, simpler version of my HF rigs and seem like a great way for me to learn about radio circuits and the tools needed to troubleshoot them. Unfortunately, we don't have anyone left in the area to tutor me so I'm relying on the internet for learning resources.

I found this one relatively recently and like the look of it. It is a kit meant to feed into a meter....but I suspect it would work into a scope as well.

It picks up RF and demodulates it.... but it is not tuned for any particular "band". That makes it great for probing around in RF circuits to see whether or not they are alive.

He asks $15 for that kit and that is not too bad.

RF Probe - Pacific Antenna

Pacific Antenna.

www.qrpkits.com

 

[guitar_199]

Does anyone know if Lou Franklin is still selling his books? I sent him an e-mail 2 days ago and haven't heard back. His website is still live with a 2022 copyright at the bottom of the pages. Everyone seems to love his books and they sound like a good source of information for me getting started on CB diagnosis and repair, so I'd like to order those.

Also, and recommended techs to follow on Youtube? I understand there is always going to be that disconnect between watching versus doing it myself, and I'm more of a hands-on learner anyway, but there is a wealth of information on youtube from the right folks. Lately I've been watching a lot from Mr Carlson's Lab, MikesRadioRepair, etc. Many of the more popular CB repair guys seems to be hit or miss on the quality of their work, and most skip past the meat and potatoes of the troubleshooting and repair processes which is what I'd like to see.

Regarding Lou's books: back in 2019 I tried "most of the year" to get in touch with him to order a set.... and it seemed he never answered. Then... around September I got an email response telling me that his "official email notification system" had been broken for a year...and someone else told him about it and he got it fixed. As a result... I used his "order form page" to put in an order... and about 2 weeks later... here they came.

I for one.. really enjoy them. I trained in electronics technology back in the 70s (another DeVry puke!) then worked digital electronics for about 10 years... then went into software in operating systems. So I have a head full of "theory" just no practice!!!!!!! The big book... really helps someone like me.... who THINKS they know what is going on.... but has "gaps" from not having "hands on" experience for a long time like many on here. Most of his explanations are pretty darned good and will "get you there".... again as HA says.... if YOU can interpret the info properly.

As for YouTube videos.... I am convinced that many of them put them up there for the sole purpose of marketing their repair service (to show you that they can fix a radio)... and there is nothing wrong with that.... not at all. But I have seen a few helpful ones from Mikes (one on using a spectrum analyzer as a signal tracer in troubleshooting frequency synthesis, another troubleshooting a low/no modulation problem). Another one ... Klondike Mike (haunts this forum!)... has videos that show some tracing level troubleshooting.

Another YouTube channel to dig into..... w2aew. There are some REAL gems in there. He has videos the demonstrate how PLL synthesizers work....WITH a REAL DEMO using a PLL and scoping it. He has another that shows demos of how small signal diodes work as "switches" (THAT concept got away from me for a while!). There are MANY other handy "technique" and "basics" videos hiding out in w2aew's channel.

 

[guitar_199]

Also, and recommended techs to follow on Youtube?

Another channel you might find handy.... is TRX Lab. Again, in here are some gems on "basics" AND repair jobs as well. You just have to hunt through his list and see what strikes you as useful.....

 

[JDE]

Regarding Lou's books: back in 2019 I tried "most of the year" to get in touch with him to order a set.... and it seemed he never answered. Then... around September I got an email response telling me that his "official email notification system" had been broken for a year...and someone else told him about it and he got it fixed. As a result... I used his "order form page" to put in an order... and about 2 weeks later... here they came.

I'll roll the dice and submit my order for the 3-pack of books and two tune up/mod reports. Worst case, a few weeks go by with no books or updates and I can always file a claim on Paypal. Hopefully that's not the case.

I'll check out those other youtubers. It is definitely hard to find quality content on there to learn from, since a lot of them don't seem to provide content with the intent of teaching you anything valuable or accurate.

 

[guitar_199]

I'll check out those other youtubers. It is definitely hard to find quality content on there to learn from, since a lot of them don't seem to provide content with the intent of teaching you anything valuable or accurate.

Like I say, some are doing to teach..... some are doing them to show you that they can repair your radio if you send it to them. Detecting "which is which" and separating them is, unfortunately, up to us. Do take a GOOD look at the w2aew and TRX Lab channels. A lot of handy "basics" hiding out in those two .... at least I have found.

And I will plug THIS one... right up front. Watching him walk down the RF-IF strip with that analyzer and explaining the mixing process and then showing you the analyzer display to back it... is pretty neat. But then... I am "easy to impress" sometimes!!!!!

 

[Handy Andy]

When you say receiver, are you referring to something like a monitoring radio that I know is within calibration? Some of the guys I've watched have a monitoring radio nearby when testing transmit, echo, etc from the radio they're working on.

Yes, the one you hear - but not always see.

There are also YT techs that simply put the radio in a PA speaker and use the Talkback function - er - NO!

What I think, believe and use, are simple CB's - known to be noisy even slightly off - but if you really want to have a good known monitor radio - best to use a Base station type - built in power supply.

You can use mobile types, but they just add to the jumble jungle of wires crossing your desk and behind the bench - the best advice here is K.I.S.S (Keep It Stupefying Simple).

Which to choose, SSB over simple AM? Also - FM is a new standard they put in place for CB, so that kinda' ups' the auntie and now narrows the selection. But if you can locate a Ham bander set up for (shh...don't tell anyone - it's our little secret - 11-Meter) and can take the time to know it inside and out - then, POW, there you go. (IN reality I can't tell you to buy this or that and you'll be ok, just get something you can learn to fall in love with and then you can set the date to get married to your job over it)

It's the little things in life that make you go crazy...

So, to protect the investment - make your first projects a set of protective devices like fuse blocks and binding posts - build your own Dummy load and put it on the back of that radio first thing - so you don't make keyup mistakes - then you can graduate to external antennas and even raise a field full of them (If your wife will let you), just get a radio - CB or Export, Base over Mobile - just prefer a radio that can be fixed or even examined and test lab'd to help diagnose the other patients that arrive across your desk.

Eventually, the simpler tools might wind up being the ones you create and build to suit your needs at the shop (if you decide to open one) like Panel meters for mA power settings, A simple diode, resistor and cap combination to make your own SINAD meter LED for Bargraphs, simple routing switches (Your IT stuff can work here too) for signal routings and branching off for the various sensors and tools - even a few things from Harbor Freight and some simple sockets from a local Menards or Lowes - goes a long way in making test jigs and holders for radios and their associated "guts" to hang out on

 

[JDE]

Yes, the one you hear - but not always see.

There are also YT techs that simply put the radio in a PA speaker and use the Talkback function - er - NO!

What I think, believe and use, are simple CB's - known to be noisy even slightly off - but if you really want to have a good known monitor radio - best to use a Base station type - built in power supply.

You can use mobile types, but they just add to the jumble jungle of wires crossing your desk and behind the bench - the best advice here is K.I.S.S (Keep It Stupefying Simple).

Which to choose, SSB over simple AM? Also - FM is a new standard they put in place for CB, so that kinda' ups' the auntie and now narrows the selection. But if you can locate a Ham bander set up for (shh...don't tell anyone - it's our little secret - 11-Meter) and can take the time to know it inside and out - then, POW, there you go. (IN reality I can't tell you to buy this or that and you'll be ok, just get something you can learn to fall in love with and then you can set the date to get married to your job over it)

It's the little things in life that make you go crazy...

So, to protect the investment - make your first projects a set of protective devices like fuse blocks and binding posts - build your own Dummy load and put it on the back of that radio first thing - so you don't make keyup mistakes - then you can graduate to external antennas and even raise a field full of them (If your wife will let you), just get a radio - CB or Export, Base over Mobile - just prefer a radio that can be fixed or even examined and test lab'd to help diagnose the other patients that arrive across your desk.

Eventually, the simpler tools might wind up being the ones you create and build to suit your needs at the shop (if you decide to open one) like Panel meters for mA power settings, A simple diode, resistor and cap combination to make your own SINAD meter LED for Bargraphs, simple routing switches (Your IT stuff can work here too) for signal routings and branching off for the various sensors and tools - even a few things from Harbor Freight and some simple sockets from a local Menards or Lowes - goes a long way in making test jigs and holders for radios and their associated "guts" to hang out on

Appreciate all the info again!

I do have various swr meters, dummy loads, different types of coax, plenty of connectors and termination tools, etc that I've collected in my time as a ham. Some of it will prove useful as I start tinkering on these cheap Cobra 29s I picked up from eBay.

I was definitely lacking in the DMM department, just cheap DMMs I've picked up up from walmart or amazon over the years. Fine for simple stuff, but nothing I'd trust to be accurate for much else, especially if working on radios. UPS guy should be delivering a Klein MM600 and a nice assortment of leads for it today. Definitely not a top shelf unit, but it'll do.

For soldering, just have a generic pencil style 110v and a Weller WLC100 that I've had for a few years and quite like. Again, not top shelf, but they work fine for what I use them for. No hot air station, and no experience there yet, but I'm intrigued enough to pick up a cheap station just to play around on some worthless PCBs.

As I mentioned earlier, I'm a hands-on learner and my biggest hurdle isn't so much the how, but the why. I can use a DMM and test a final, resistor, capacitor, test for continuity, etc. However, if you sat a no-rx or no-tx Cobra 29 down in front of me, no idea where to start, and if I did know which components to check first, parroting what I read or saw online, I wouldn't understand why I'm testing those components first and that is the downfall of relying on youtube or forum posts. I have a good head start in this field, more than the average joe, but achieving that level of fully understanding what this stuff is and why/how it does what it does is pretty much my only roadblock and I'm very much interested in getting to that point.

 

[guitar_199]

I'll check out those other youtubers. It is definitely hard to find quality content on there to learn from, since a lot of them don't seem to provide content with the intent of teaching you anything valuable or accurate.

One more of Mikes that is really good IMHO.....

troubleshooting a "no modulation audio" issue..... on camera....