Another great tutorial Peter. Thanks for sharing. I do agree it is hard to beat an analog meter for testing receiver signals. A lot of folks say use digital because analog is useless these days. Those folks do not work with RF lol. Thanks Peter
I agree Buddy, I miss my older analog volt meters , I am slowly building up my bench equipment , radio shops AKA VCR shops are non existing in my town ...... I will be a welcome sight when I hang my Shingle outside .....
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Peter, thank you for this very detailed and concise explanation using both the Spectrum Analyzer and True RMS volt meter with applied math.
The power reduction circuit for the LED to work is a PWM Circuit like a Switch-mode Power Supply - Mike at Mike's Radio Repair showed a San Quan Frequency Counter in one of his repairs that created all that Static Noise 60 Hertz hum.Bell's CB and others have had problems with Galaxy Radios Starlight LED Face-plate with the high pitched hum - same problem the LED Driver Display Power Source.
One thing to note when doing the math. You can save having to type in a lot of stuff if you don't bother with the X10-3, etc. In fact you only need to type in 28 over 4 to get the result.
Great minds think alike Mike...as long as the exponents are the same you can disregard them but that could be confusing to a newcomer at first so doing the long math is probably worthwhile until they realize the shortcut method. TNX Peter, another great tutorial. 73 - Dino KL0S
A great lesson. And beside the maths the conclusion for beginners is: You can do a lot work on receivers with a pencil, a sheet of paper and 100 bucks on ebay. It doesn´t take a lot of money but brain to start. THX to TRX ;-) Well done, Peter.
Well, I hope that you would some day be able to test and debunk the IC-9700 horrible preliminary reviews that has started to shown up on internet... You seem to have everything needed to show the whole procedure on you to test the sensitivy, stability and what ever else there is to know on a radio... That would be really nice to see on a brand new radio that does not need repair or tuning, just reading values for the receiving, stability and output power and so on ! I hope you'll be able to do this one day !
Hello Peter, you always inspire me with your videos and this one is no exception. I downloaded Audiotester V3 and i was impressed with it. With this software it's possible to read the signal to noise level from the screen! I checked it with the way you suggest with signalgenerator and a ac millivoltvolmeter. Thank you Peter that i learned from you.
Hello Peter, how are you? I know, you do not have much time, but I need some help... I purchased a CMS54 and my monitor have some issues, I'm trying to find the service manual or schematic, but I have no lucky. Please, can you buy it from R&S? Just tell me the value... Thanks in advance. Yvo from Brazil
If you use a really cheap DMM which might be "average" responding or a VTVM which are often "peak responding"(having a detector and LPF), the measurement of the noise would have a large error. That would make for an interesting follow-up demo.
eventually I switched over to the Sinader because I was working with radios that had discriminators which were very hard to align using signal to noise.
In der Zeichnung von 32:30 bis ca. 34:00 sieht es so aus als könne man den SNR direkt im Spektrum ablesen. Der Abstand des Peaks zum Noise-Level ist aber von der Messbandbreite (RBW) des Spektrumanalysers abhängig. Aber das hast du wohl absichtlich vereinfacht, damit es einfacher zu erklären ist...
Hi Peter! To execute this measure, the AGC control must be disabled? I have tested an old AM cb radio, but when i put -107dbm signal into radio i read about 800mV (S+N)…when a noise floor is 40mV 🤷♂️
Good question. At this very weak signal level of -107dBm input level, the AGC should be automatically off (maximum receiver gain) You likely need to get close to S9 (50uV signal) before AGC action starts. recall that there is a 6dB ratio between S units, so -107dBm is a faint signal equivalent to about S3
Very informative video yet again Peter. Do you ever dabble in any of the digital voice modes such as DMR, D-STAR, Fusion, etc? I don't think I have seen you do any video on either repair of any digital radio hardware or a tutorial on something similar to today's video, for example receiver and power measurements for digital radio? Just a thought... Great work Peter and best wishes, 73, Brian EI8EJB
Thank you Brian! Yes already thought about the subject. That would mean a hole series which is very time consuming and I have a huge lack of time....But more serious is the fact that the Retevis DMR radios are so cheap that a repair does not make sense economically ..., that is the main reason for no repairs yet...73
Hi Peter! In this video you calculate S+N/N. In more radio manual’s are reported an example: sensitivity 1.0uV for 10 dB S/N (…not S+N/N). How i can meseure 10 dB S/N ?
The noise accompanying the signal is generally so much smaller than the receiver noise, it can be neglected. S/N is essentially same as S+N/N in his demonstration.
Cordless drill battery chargers will also cause noise when they are charging in the same area as the radio and some Fluorescent bulbs will cause interference..
How do you connect the signal generator to get the right frequency for the receiver test -is there a setting for 27Mhz and a switch for the 1Khz tone that is injected? What quality generator is required for alignment?
Hello,Sir I hope you are OK ,and everithing go well.I send this message,because I realy need help from a profesional.If you are agree,I will send you a panasonic schematic,wich have a stand by voltage problem(it is missing)and the driver is a FAN6755U.I am not able to understand whthe IC don.t start.In the datasheet ,said,that need a 7,5v on VIN pin to start ,but i have only 2.8v.PLEASE ,give me a hand with that,and if you want to help me,i will send you the schematic .Thanck a lot
worroSfOretsevraH actually he calculated the (s+n)/n. The voltmeter measures the sum of the signal, the noise, the distortion, everything in the passband. The sinad measurement uses a notch to exclude everything but the signal. He’s showing this technique is pretty close, using simpler equipment
Another great tutorial Peter. Thanks for sharing. I do agree it is hard to beat an analog meter for testing receiver signals. A lot of folks say use digital because analog is useless these days. Those folks do not work with RF lol. Thanks Peter
I agree Buddy, I miss my older analog volt meters , I am slowly building up my bench equipment , radio shops AKA VCR shops are non existing in my town ...... I will be a welcome sight when I hang my Shingle outside .....
Peter, thank you for this very detailed and concise explanation using both the Spectrum Analyzer and True RMS volt meter with applied math.
Thank you again for sharing your knowlege. You are an excellent teacher and I learn a lot from your videos.
Peter thanks for the time you take to make the video.
The power reduction circuit for the LED to work is a PWM Circuit like a Switch-mode Power Supply - Mike at Mike's Radio Repair showed a San Quan Frequency Counter in one of his repairs that created all that Static Noise 60 Hertz hum.Bell's CB and others have had problems with Galaxy Radios Starlight LED Face-plate with the high pitched hum - same problem the LED Driver Display Power Source.
Another great video Peter - thank you for your education help.
Hi Peter, Another very nice tutorial. You explained the subject very well. Thanks 73
Thank you Larry, glad that you like it 73
You are are a great teacher, Thank you again for the very best videos on you tube
Thank you Dennis for your kind words! 73
One thing to note when doing the math. You can save having to type in a lot of stuff if you don't bother with the X10-3, etc. In fact you only need to type in 28 over 4 to get the result.
Great minds think alike Mike...as long as the exponents are the same you can disregard them but that could be confusing to a newcomer at first so doing the long math is probably worthwhile until they realize the shortcut method. TNX Peter, another great tutorial. 73 - Dino KL0S
You are totally right Mike but my concern was like Dino already said....Thanks for comment 73
Thanks Dino, totally agree with you 73
Shortcuts are great when you already understand what is going on. Not so great for folks trying to figure it out for the first time.
A great lesson. And beside the maths the conclusion for beginners is: You can do a lot work on receivers with a pencil, a sheet of paper and 100 bucks on ebay. It doesn´t take a lot of money but brain to start. THX to TRX ;-) Well done, Peter.
Thank you Olaf 73
Well, I hope that you would some day be able to test and debunk the IC-9700 horrible preliminary reviews that has started to shown up on internet... You seem to have everything needed to show the whole procedure on you to test the sensitivy, stability and what ever else there is to know on a radio... That would be really nice to see on a brand new radio that does not need repair or tuning, just reading values for the receiving, stability and output power and so on ! I hope you'll be able to do this one day !
Hello Peter, you always inspire me with your videos and this one is no exception. I downloaded Audiotester V3 and i was impressed with it. With this software it's possible to read the signal to noise level from the screen! I checked it with the way you suggest with signalgenerator and a ac millivoltvolmeter. Thank you Peter that i learned from you.
Hello Peter, how are you?
I know, you do not have much time, but I need some help...
I purchased a CMS54 and my monitor have some issues, I'm trying to find the service manual or schematic, but I have no lucky.
Please, can you buy it from R&S? Just tell me the value...
Thanks in advance.
Yvo from Brazil
Thanks for the tutorial Peter interesting as usual. Robert.
Great video, very helpfull and grundig explaination. Now spectrum analyzers are not that strange.
I think you made a video a while back on a homemade meter for adjusting the receive on radio's ??? Which one was that ????
I believe you mean video #50?
What audio software are you using?
Great video as always. Also dBm is 10 log, where as voltage is 20 log.
So it is :-) Thanks for watching 73
If you use a really cheap DMM which might be "average" responding or a VTVM which are often "peak responding"(having a detector and LPF), the measurement of the noise would have a large error. That would make for an interesting follow-up demo.
eventually I switched over to the Sinader because I was working with radios that had discriminators which were very hard to align using signal to noise.
Thanks Peter. very nice tutorial.
In der Zeichnung von 32:30 bis ca. 34:00 sieht es so aus als könne man den SNR direkt im Spektrum ablesen. Der Abstand des Peaks zum Noise-Level ist aber von der Messbandbreite (RBW) des Spektrumanalysers abhängig. Aber das hast du wohl absichtlich vereinfacht, damit es einfacher zu erklären ist...
Do you have to make sure that the receiver's AGC circuit is turned off for this measurement?
At the limit of the receiver’s sensitivity where this test is done, the AGC should not be active regardless of the setting.
Great video one of the best explanations thanks for sharing regards Chris
Thanks Peter for a very good informative video.......................................Berni
Thank you for sharing, Peter
Thanks for watching Nikola
hi Peter!
what software an/ord hardware can I use to display the audio signal? an R&S analyzer is beyond my possibilities! hahaha
Hi Peter! To execute this measure, the AGC control must be disabled? I have tested an old AM cb radio, but when i put -107dbm signal into radio i read about 800mV (S+N)…when a noise floor is 40mV 🤷♂️
Good question. At this very weak signal level of -107dBm input level, the AGC should be automatically off (maximum receiver gain) You likely need to get close to S9 (50uV signal) before AGC action starts. recall that there is a 6dB ratio between S units, so -107dBm is a faint signal equivalent to about S3
@@emylrmm tnx !!!!!
Very informative video yet again Peter. Do you ever dabble in any of the digital voice modes such as DMR, D-STAR, Fusion, etc? I don't think I have seen you do any video on either repair of any digital radio hardware or a tutorial on something similar to today's video, for example receiver and power measurements for digital radio? Just a thought... Great work Peter and best wishes, 73, Brian EI8EJB
Thank you Brian! Yes already thought about the subject. That would mean a hole series which is very time consuming and I have a huge lack of time....But more serious is the fact that the Retevis DMR radios are so cheap that a repair does not make sense economically ..., that is the main reason for no repairs yet...73
Point taken! Thanks Peter :)
Another great teaching video, Paul. What are you using for your your Audio SA? Thanks Fred
Thank you Fred but my name is Peter :^) My audio SA is audiotester.de 73
Hi Peter! In this video you calculate S+N/N. In more radio manual’s are reported an example: sensitivity 1.0uV for 10 dB S/N (…not S+N/N). How i can meseure 10 dB S/N ?
The noise accompanying the signal is generally so much smaller than the receiver noise, it can be neglected. S/N is essentially same as S+N/N in his demonstration.
@@emylrmm tnx !!!
if you would be using the HP3400a would you get also the distortion?
No as long we are talking about THD...
Cordless drill battery chargers will also cause noise when they are charging in the same area as the radio and some Fluorescent bulbs will cause interference..
Is the audio volt meter RMS? Great videos thanks !
How do you connect the signal generator to get the right frequency for the receiver test -is there a setting for 27Mhz and a switch for the 1Khz tone that is injected? What quality generator is required for alignment?
William, some of the requested infos you will find in video #159, best 73
Thank you.
Very helpful, thanks!
Do you also have a German channel? :-)
Great videos . I wonder how you find him for repair work? Or is it a secret?
Not sure what you mean Josh...
He wants to know how to hire you for repair work.
Would be a good way to try out my Heath-Schlumberger SM-22.
good luck with testing 73
Awesome thank you very much once again. Reminder: db voltage chart ? ;-)
Hi Leo, thank you! What is your e-mail. 73
TRX Bench PA1LDB@veron.nl Will work Thanks a lot
Great.... Grazie
Excellent
You only calculated the S/N ratio, not the S+N/N. That's why the result was lower than the tester showed.
This demo gives you some idea of how bad even 20dB S/N ratio sounds like.
A 10dB S/N would be barely perceptible phone (speech) on AM
You have 50 hz power supply noise in there, 120db down.
120 dB down is pretty much the definition of “in the noise”. It is utterly insignificant.
Hello,Sir
I hope you are OK ,and everithing go well.I send this message,because I realy need help from a profesional.If you are agree,I will send you a panasonic schematic,wich have a stand by voltage problem(it is missing)and the driver is a FAN6755U.I am not able to understand whthe IC don.t start.In the datasheet ,said,that need a 7,5v on VIN pin to start ,but i have only 2.8v.PLEASE ,give me a hand with that,and if you want to help me,i will send you the schematic .Thanck a lot
Solar panels are the worst one.
You only calculated the S/N ratio, not the (S+N)/N. That's why the result was lower than the tester showed.
worroSfOretsevraH actually he calculated the (s+n)/n. The voltmeter measures the sum of the signal, the noise, the distortion, everything in the passband. The sinad measurement uses a notch to exclude everything but the signal. He’s showing this technique is pretty close, using simpler equipment