Mike this video could not have come at a better time. I was just talking about the fact that I cannot really use my oscilloscope to troubleshoot the home brew receiver (part of a transceiver) because the levels are just too low to see. But the funny part is I have a tektronix spectrum analyzer sitting next to the device and I never thought of using it for tracing through the circuits. I'm glad you mentioned DC block so I don't do something stupid again. Thanks for the great video Mike and 73's Dale
It´s a very good tool to have! Unfortunately not all workshops can have a spectrum analyzer! One day i will get there! Nice video Mike. Thanks for sharing. We all learn a lot with you. 73
I'm guilty of leaving the DC block off the input of my SA periodically...the N-to-N block I have is kinda long and is actually kind of a hazard where the box is on my bench...but as you say forewarned is forearmed! (Trust that Rigol 50V DC spec? Ehhh, well at least until I get burned!). Nice video Mike, great for beginning troubleshooters.
@mikesradiorepair would be great to see the specifics on your probe setup from tip to connection to SA. What do you use and what protections it provides. Is it a purchased DC block or DIY? Is the probe on 1x or 10X. It looks like a great setup and provides protection needed. This kind of knowledge can save someone $$$$. Great video!!!
Good video Mike. Very good tips. It's mostly common sense... although "common sense" is not very common LOL. Thanks for sharing it with us. Regards, Frank K7RMJ
Very nice, MIke! This was really timely for me. I'm just about to trace a signal on a Kenwood TS-590s that is deaf on AM, and planned to use my Spectrum Analyzer (I don't have a decent signal tracer online yet). I was wondering what to do about DC blocking, and voila, 2 days later, you post a video! Thanks for hearing the vibe! Can you give more information on the DC block you use? I've googled around and see them all over the map in terms of pricing. I don't want to spend a mint, but I don't want to buy something worthless either.
I use a Mini-Circuits BLK-89-S+ on my SA. You can get them with whatever RF connector you need. I also use a limiter that will clamp if the input gets too high. www.minicircuits.com/WebStore/dc_blocks.html www.minicircuits.com/WebStore/Limiters.html
Great way to look at a receiver nice video ,Ihave a Marconi 2945 and i will be looking at my 148 in this way. Be good to see an alignment done with a spec analyzer would there be any advantages ? thanks again for great videos
Where do you get uniden service manual? i called them and they absolutely refused to share and said they do not give that info to any distributors and all repairs are done by them in texas...
Either have to search the internet and pray you can find one there or if it's not available you have to reverse engineer the radio and make your own service manual. I have had to make my own service manuals for numerous radios over the years.
Mike, is there any way the 455 filters can stop transmit in a radio, too? Or, is it just receive only? I have a Uniden PRO-710e I'm working on that has no receive and no transmit. Trying to get any ideas I can! Thank you!
Mike, How is it the 50 ohm input impedance of your spectrum analyzer is not loading the radio's IF section to the point it changes how that section works? An ordinary scope has 1M-ohm input. Won't load the circuit.
The scope probe is set to 10X position. The 10X position adds a 9Megaohm resistor in series. That much resistance makes for nominal loading of circuits.
@@mikesradiorepair Thank you for the prompt reply. Wow! That makes the sensitivity of the Spectrum Analyzer even more impressive. It's seeing a voltage roughly 1/180,000th what's on the trace the probe is touching.
@@TheCondoInRedondo Remember, a spectrum analyzer can measure signals lower than -120dBm. -120dBm is 225nanoVolts or .000000225Volts. In the grand scheme of things the loss from adding 9 Meg of resistance inline with the spectrum analyzer is small in comparison to how low it can measure. Remember, I was feeding in (as far as radio signal strength goes) a huge signal at -35dBm.
would a Keysight/Agilent E4406A Vector/Spectrum Signal Analyzer with Rear Output and 202 be a good entry lvl signal analyzer for cb radio repair? I do board lvl repair of cell phones and want to get into working on cb’s. I’m trying to put together the the test equipment needed, but don’t want to sink a ton into it at first if it doesn’t prove profitable in my area.
I really have no idea, I don't own one. You would need to research it and see if it meets your needs. Most of this type of equipment was designed for base band / cell phone service but has workarounds for using in other applications.
This is one of the more more difficult problems to troubleshoot "no receive". Possibilites are many..Injecting and tracing a signal is really the only way..
The probe tip only fits the probes it came with made by Probe Master. Probe Master makes high quality after market oscilloscope probes and other meter probe kits. All high quality stuff.
Mike you need to write an ebook like the Lou Franklin ones which are out of print so prices have gone through the roof, Amazon want 1000 bux for a copy FFS!
Called him from the UK this morning and he says he has health probs on his answering machine, when you try purchase the book it returns an error on his site which hasnt been updated since 2014. anyways its not an Ebook which you could deliver much more cheaply and quickly, I ordered mine from the USA costing $120. you need to do something similar first before your electronics course imho thanks for the reply im a big fan keep up the good work Mike.
Suggestion: use 2 assistant cameramen using tripods as necessary. One to cover the scope presentation, the other to follow your probe. You wear the microphone to let us know what you are doing. By using the 2 cameramen, you can focus on your work and narration. Just saying.
This smart man needs way more light.
That was a great show of how to troubleshoot using the right equipment. Great video Mike.
I wish I had just a quarter of your knowledge. I would love to have a chance to pick your brain.Another great video !
Mike this video could not have come at a better time. I was just talking about the fact that I cannot really use my oscilloscope to troubleshoot the home brew receiver (part of a transceiver) because the levels are just too low to see. But the funny part is I have a tektronix spectrum analyzer sitting next to the device and I never thought of using it for tracing through the circuits. I'm glad you mentioned DC block so I don't do something stupid again. Thanks for the great video Mike and 73's Dale
It´s a very good tool to have! Unfortunately not all workshops can have a spectrum analyzer!
One day i will get there!
Nice video Mike. Thanks for sharing.
We all learn a lot with you.
73
Excellent video Mike. If you have a level diagram like Kenwood is doing it you really can determine if all is working right . Thanks for sharing...
Mike ... what a spectacular video. This one was an unbelievable eye-opener. Thank you.
What a great video. I love these. Thanks
I learnt a lot from this video, thanks!
I'm guilty of leaving the DC block off the input of my SA periodically...the N-to-N block I have is kinda long and is actually kind of a hazard where the box is on my bench...but as you say forewarned is forearmed! (Trust that Rigol 50V DC spec? Ehhh, well at least until I get burned!). Nice video Mike, great for beginning troubleshooters.
@mikesradiorepair would be great to see the specifics on your probe setup from tip to connection to SA. What do you use and what protections it provides. Is it a purchased DC block or DIY? Is the probe on 1x or 10X. It looks like a great setup and provides protection needed. This kind of knowledge can save someone $$$$. Great video!!!
Good video Mike. Very good tips. It's mostly common sense... although "common sense" is not very common LOL. Thanks for sharing it with us. Regards, Frank K7RMJ
You probably should of adjusted the 10.24MHz crystal before adjusting the RX alignment.
Great video, easy to follow, thanks. Where can I get one of those long, skinny probes, please?? Ordering information, please!
Mike another excellent video, may I ask what model narda dc block are you using?
Thank you Mike for another great video.
Thank you very informative.
As far as your parts replacement comment, I am still there now, sometimes I feel like a blind dog in a meat house 😂
Another great video!!! Nice job Mike
Many thanks Mike. I'm off to practice with my Rigol 815tg Analyser.
Very nice, MIke! This was really timely for me. I'm just about to trace a signal on a Kenwood TS-590s that is deaf on AM, and planned to use my Spectrum Analyzer (I don't have a decent signal tracer online yet). I was wondering what to do about DC blocking, and voila, 2 days later, you post a video! Thanks for hearing the vibe! Can you give more information on the DC block you use? I've googled around and see them all over the map in terms of pricing. I don't want to spend a mint, but I don't want to buy something worthless either.
I use a Mini-Circuits BLK-89-S+ on my SA. You can get them with whatever RF connector you need. I also use a limiter that will clamp if the input gets too high.
www.minicircuits.com/WebStore/dc_blocks.html
www.minicircuits.com/WebStore/Limiters.html
Thanks Roy!
I think a better way to describe the 1st IF is that the receiver frequency is the VCO frequency plus the 1st IF frequency.
Wow great video and info.
Thanks for the vid. It was very interesting.
Mike are those filters a parallel tank circuit with no resistance?
Great way to look at a receiver nice video ,Ihave a Marconi 2945 and i will be looking at my 148 in this way.
Be good to see an alignment done with a spec analyzer would there be any advantages ?
thanks again for great videos
Mike, Great video. Question, any suggestion for a DC block to use on the Red Pitaya?
I guess you could use the spectrum ann, in the SDRplay radio right????
Very good video but how can I trace a very small signal without a spectrum analyzer? Will a homebrew audio/rf signal tracer work?
Where do you get uniden service manual? i called them and they absolutely refused to share and said they do not give that info to any distributors and all repairs are done by them in texas...
Either have to search the internet and pray you can find one there or if it's not available you have to reverse engineer the radio and make your own service manual. I have had to make my own service manuals for numerous radios over the years.
Mike, is there any way the 455 filters can stop transmit in a radio, too? Or, is it just receive only? I have a Uniden PRO-710e I'm working on that has no receive and no transmit. Trying to get any ideas I can! Thank you!
No, receive only.
@@mikesradiorepair Thank you! Do you still repair radios?
What bandwidth do you usually try to use for filtering - I see they have a large selection of bandwidths to choose from?
What DC Block are you using?
Mike, How is it the 50 ohm input impedance of your spectrum analyzer is not loading the radio's IF section to the point it changes how that section works? An ordinary scope has 1M-ohm input. Won't load the circuit.
The scope probe is set to 10X position. The 10X position adds a 9Megaohm resistor in series. That much resistance makes for nominal loading of circuits.
@@mikesradiorepair Thank you for the prompt reply. Wow! That makes the sensitivity of the Spectrum Analyzer even more impressive. It's seeing a voltage roughly 1/180,000th what's on the trace the probe is touching.
@@TheCondoInRedondo
Remember, a spectrum analyzer can measure signals lower than -120dBm. -120dBm is 225nanoVolts or .000000225Volts. In the grand scheme of things the loss from adding 9 Meg of resistance inline with the spectrum analyzer is small in comparison to how low it can measure. Remember, I was feeding in (as far as radio signal strength goes) a huge signal at -35dBm.
Hi Mike, could you use a hf home made sniffee to get these values at the IF stages?
Cheers
Andrew
I was wondering where I could buy the long probe tip
would a Keysight/Agilent E4406A Vector/Spectrum Signal Analyzer with Rear Output and 202 be a good entry lvl signal analyzer for cb radio repair? I do board lvl repair of cell phones and want to get into working on cb’s. I’m trying to put together the the test equipment needed, but don’t want to sink a ton into it at first if it doesn’t prove profitable in my area.
I really have no idea, I don't own one. You would need to research it and see if it meets your needs. Most of this type of equipment was designed for base band / cell phone service but has workarounds for using in other applications.
What brand of DC block do you use. does it have any attenuation? I find DC blockers but they have 20db attenuation.
+Harvey Bauss
It is a Narda brand and does NOT have any attenuation other than the normal loss associated with any device.
Hi Sir can you tell me all components on this canal line , probe to SA (dc block name type) ?
This is one of the more more difficult problems to troubleshoot "no receive". Possibilites are many..Injecting and tracing a signal is really the only way..
you should half split bracket...
It hard to find some one were i live to work on cb
where did you get the long nose attachment for the scope probe....
The probe tip only fits the probes it came with made by Probe Master. Probe Master makes high quality after market oscilloscope probes and other meter probe kits. All high quality stuff.
Thanks. I’ve got some dvm probes by them.
Mike you need to write an ebook like the Lou Franklin ones which are out of print so prices have gone through the roof, Amazon want 1000 bux for a copy FFS!
Umm, I'm pretty sure he started printing them again. They are now spiral bound. Check his website.
Called him from the UK this morning and he says he has health probs on his answering machine, when you try purchase the book it returns an error on his site which hasnt been updated since 2014. anyways its not an Ebook which you could deliver much more cheaply and quickly, I ordered mine from the USA costing $120. you need to do something similar first before your electronics course imho thanks for the reply im a big fan keep up the good work Mike.
if they are readily available then why do Amazon Uk want 1000? answer they know its now hard to get
www.cbcintl.com/urbook.htm
In stock and currently for sale on Lou's website.
Never going to happen. I don't have a year or two to take off to write a book.
Suggestion: use 2 assistant cameramen using tripods as necessary. One to cover the scope presentation, the other to follow your probe. You wear the microphone to let us know what you are doing. By using the 2 cameramen, you can focus on your work and narration. Just saying.
Kind of hard to have assistants do camera work when I'm the the only one here. :-)
@@mikesradiorepair I just knew you were still out there somewhere !