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- Опубліковано 15 лип 2024
- I recently picked up this Sinadder 3, a very useful tool for FM receiver alignment. This video reviews the definition of SINAD (SIgnal to Noise And DIstortion), and shows how the Sinadder 3 makes the measurement. The block diagram is reviewed and as well as a quick walk-through of the schematic diagram. Finally, I demonstrate the basic operation of the Sinadder 3 and how it can be used to help with the alignment of, and check the sensitivity of a common FM receiver (Kenwood TS-231A 2m ham radio). Helpful links:
SINAD wiki article:
en.wikipedia.org/wiki/SINAD
Sinadder 3 Manual:
repeater-builder.com/test-equi...
Kenwood TM-231 Service Manual:
www.radiomanual.info/schemi/KE... - Наука та технологія
A very handy instrument Alan, I’ve been using one daily for years working on CB radios everything from early 60s to late 2010s.
Extremely handy for doing receiver alignments. I use a lot of BK Precision gear, HP SA and tracking generator and Tektronix 2465B scope plus other test equipment.
I do have a HP 8924C but i only have it on the bench for radios outside of 27MHz as I find the BK equipment very fast to use.
Love your very informative videos.
Excellent video, and I love the old piece of test equipment that you have! Thanks for sharing the schematic as well.
This brought back some memories. I first started using this exact instrument about 35 years ago while working for a communications repair shop. Haven't had the need to use one in the past 25 years.
This video reminded me of my days at Motorola (1979-1998) repairing portable communications equipment. I had that same SINAD'er at my work bench. Even though I had the best service monitor at the time -- with a built in SINAD meter -- I mostly relied on the Helper.
Never a dull moment on your channel. Thanks for sharing!
I just repaired my one. The SINAD function pinned the needle. It was an oscillator. It turned out one of the 10nF in the notch circuit had failed open circuit. I changed some of the electrolytic capacitors at the same time. Works OK for looking at FM, AM and SSB Sinad
The unit I have had another double ganged potentiometer on the front panel, which tuned the notch over a range. Thought it might have been part of the reason it was unstable. It looks like a homegrown modification. Disconnected now.
Might try your notch board in a SINAD meter circuit.
Thanks for posting this. Wish I had one of these back in the day when putting together those TenTec transceiver kits!
Alan, thank you once again for sharing. I enjoyed this new video concise and very clear. SINAD figure is now clear for me. Have a good one..
Yet another demonstration of your teaching skills. Clear concieus and to the point!
An excellent clear and concise explanation and demonstration. Thank you!
Thank you for sharing Alan. I always had my eye on one of these units from Sinadder, even though my two test sets have SINAD built in. Looks like a quality unit.
Well done video. Appreciate the explanation of the Sinadder 3 internals and the description of how to use it.
That was a nice explanation. It was nice to see the AGC section.
I did a demo last week at my radio club of my newly repaired Stabilock 4040 and I tried to explain why SINAD measurement equipment is useful to a radio amateur. Suffice to say you explained it far better than me, infact I might show them this video and explain to them "This is what I wanted to say"
Thanks for another great demo.
Great demonstration of he Sinadder Alan. Thanks for sharing
Thanks Bud.
Thanks for the video. Extremely useful when aligning repeater receivers. Mine is a "digital" version in my HP 8924C.
Just discoverex your channel a few days ago and really like what I see! Now my big issue is catching up on almost 300 videos. As an EE I'm especially intrigued. You go over stuff I forgot about years ago....
Hopefully the video index file (linked on the main channel page) will help you to find the videos that interest you.
You got the thumbs up before I hit play, always good Alan!
I had no idea Tektronix was making scopes so small! Incredible how technology is changing! LOL. - 9:25
Those flash drives are awesome. I want one.
€3,250 gasp
Thank you for posting this, Alan. I was curious how it actually works
Thank you, Alan! I was given a crippled (non-op) SINADDER 3 that has been sitting on a shelf for decades! Now that I have seen the schematic, theory and application, I am confident I can repair it! Now to find that schematic! Thanks again, Alan for your outstanding/professional presentation! A.
Did you find the schematics? I actually found a complete documentation online.
Great Channel !. May Almighty grant you a long healthy life to create these amazing videos.
I used a Sinadder for a long time. It worked very well. I didn't know that they were no longer available, but I retired 11 years ago.
Thanks for the great video Alan.
Neat piece of old gear. May have to look for one of them. Nice demo! 73's RDU
Hard to find, Bob. I got lucky at the FLARC auction on black friday.
Pretty sweet! Simple and clever.
It occurs to me... it might be fun to see FFT's of the pre- and post-filtered signals.
Thanks very much for the video. I’ve got a Sinadder 3 and the Motorola one also. I prefer the Sinadder though for checking sensitivity on CB radios.
neat and informative as always, thank you.
When my IFR starts acting up I pull out my Sinnader 3 and crank up the RF signal generator and it works like a charm even though it's old school. I did move the rear panel input BNC to the front panel to make that connection more convenient. Thanks for sharing Alan! 73 - Dino KL0S
I'll have to consider making such a mod on my unit too.
It's a snap to do, there's plenty of real estate inside and it fits nicely in the lower right hand corner of the front panel....looks like it was meant to be actually.@@w2aew
@@PapasDino Mine doesn't have a BNC on the rear panel, it has the test lead permanently attached (through the panel), right to the circuit board.
Hmmm, it's been a while. Wait, I remember, that BNC was already on the front panel, the guy I got it from put it there in parallel with the rear panel lead; I simply got rid of the rear panel connection. While you're inside you may want to touch up the alignment as mine was just a bit off as I recall. If you need a copy of the manual I can send it along.@@w2aew
@@PapasDino I already touched up the alignment (adjusted the 1kHz source, adjusted the AC voltmeter accuracy, adjusted the notch filter, and adjusted the SINAD accuracy). I have a PDF of the manual, but it isn't a super copy. I also noticed a few differences between the PCB layout in the manual and the actual PCB, so I wonder if there were different variations. It'll be interesting to see what your manual shows.
I never understood how this works. Now I know that it is the AGC amp that does the magic. That 1 KHz notch filter could have been a little tighter IMHO, but I guess it serves the purpose as it is. Great video!
Yeah, it it could be sharper. I should measure the width at the 12dB SINAD level, that would give a better indication of the filter's Q. I'd like to compare results of this inexpensive meter to a more professional piece of equipment, but I don't have access to anything else at this point.
Another great video Alan, though I am late finding it. I also have a Sinadder, very popular here in the UK too in the past. A friend built a clone, I think he had problems with that AGC circuit, I suspect he used the wrong type FET. Very useful units and sometimes just handy to have an audio amplifier and speaker in a box too.
my hp 8921a has one built in. Very important part of my test bench
Dear Alan,
Thank you very much for your great videos ! (I'm a fan)
As suggestion could you give a "back to basics" on radio transmission (RL tank, oscillation, how was the technics at the time of RL, how is the evolution until Quartz etc... )
I think it could be very interresting for many elect. amateurs.
Bye ! Excellent Videos !
Happy New Year.
Merry Christmas And Happy New Year .
Nice explanation. Thanks for sharing
Never seen one before, Thanks.
Very Interesting, Thank You! Happy New Year!
Useful video 👍
Thanks for uploading it. I need revised this topic. Thanks
A great explanation of SINAD and how it works. I knew the basics but this really helped me refine what I knew. You got my thumbs up and subscribe.
One really minor thing, you were referring to voltages in the spec as nano volts. But the symbol in the spec was micro volts. A little thing and I'm sure just a slip of the tongue. Thanks for a great video!
The specification says 0.16 microvolts, and I stated 160 nanovolts, which is the same quantity.
And I missed that, lol my mistake. I thought I heard the same number. Sorry about that.
Thanks for video! I use HP8920A test set for SINAD but want to make the same compact device for outdoor tests
Always enjoy "your stuff"
👍Thank you sir.
Great video
Great! as always. I really like your videos.
I really miss the Sinadder's analog meter - I find it harder to align receivers with the digital equivalent on today's service monitors - trying to watch a bar graph representation is not the same as the smooth movement of a d'arsenval meter...! As always - a great video. Thanks!!
Hi Alan,
Very informative video. Excellent visuals. 73 WB3BJU
Another great video! I thought I understood what SINAD was, thanks for making it click !!!
73 N8AUM
This is definitely a nifty gadget, and I'm thankful that the manual I downloaded from the above link contains the schematics, I can see where at least some parts of this are going to be useful in the context of the audio stuff I like to mess around with. I see a few of the comments below where people are talking about building one, or making a kit, or similar. How is any of that going? I'd sure like to hear about it if there's any significant progress...
Thanks Alan.
Very interesting thanks for Posting.
Thanks a lot, 🌷 interesting!
Gracias señor por la explicación mi Sinadder 3 se descalibro...!!!! mide -6 dBM cuando le aplico 0,35uV. Ahora se como calibrarlo. Debería medir 0,35uV/12dBM o 0,50uV/20dBM...!
Saludos desde Quito-Ecuador...!
Bought one at a Ham swap meat, neither me or the seller knew what it was, but, the price was right :)
excellent instrument but in my country very difficult to be found the sale I came to think of putting together a unit based on the diagram of Sinadder 3, as soon as I start my holidays at the end of the year I will carry out this assembly ... Thanks for sharing Alan! 73
@@jim9930 , thank you very much for the tips are very valuable post need to mount this instrument for my daily use..........Thank you Jim Mitchell.
@@jim9930 I keep trying to understand both the osc and filter circuits, but they use constructs I have difficulty analyzing entirely. Could you explain the process of picking the value of R19 in the filter? I'd also like to understand the oscillator circuit, especially the R50-R53, C24 feedback section.
An indispensable tool for doing transceiver alignments. I have a few of the Helper Instruments models, two of the Motorola units and it's built into all my communications test sets. I gave one of the Sinadder units to Buddy (The Radio Shop) some time ago. They also work equally well for doing AM and SSB alignments. Did a video a while ago describing the difference between SINAD, THD and THD + Noise.
I’d like to see that video. Can you share the link?
@@w2aew
Well I would love to but I can't find it. I don't know what the heck is going on but it appears to have vanished from UA-cam. I know I posted it because I remember Dino emailing me the notes he took after watching it and that he presented at their club meeting. Shoot I even printed the "cheat sheet" he emailed me. Going to have to investigate further what happened to the video.
Is this the video Mike?: ua-cam.com/video/kMdJY69g97A/v-deo.html ~Jack, VEG
@@VintageElectronicsGeek I looked at that one, but it's not the one that describes the differences.
@@w2aew
Nope, that's not it. I looked and looked again and the video appears to be gone. Ironically Dino emailed me asking me if I had a copy of the notes he had emailed me that he took when he watched the "missing" video. Luckily I did still have them and all the notes I used to make the video so I sent them to him. Looks like the UA-cam monster ate my video. Guess I will have to do the video again. Uggg....
I have one myself and still in use
Thanks
Hi,I have found your videos to be interesting and useful. I was searching for a video from long back but i have not found any where. can you please do some experiments on LO leakage optimization practical video it will be very useful to understand the concept of DC offset in zero IF receiver.
Nice demonstration! Is there any tutorial video how to measure selectivity of an VHF or UHF FM receiver?
Would be an interesting project to do this digitally using mic input on a computer and a freeware app like Scilab (Matlab substitute). A little sinewave least squares fitting routine would be the main coding work. Good news is you could have it calculate the exact frequency around 1khz.
I think i have seen something like this before in an audio testing software, but i can't remember the name right now. You would need a decent audio interface (mic/line inputs in onboard soundcards are too crappy) and you need to calibrate it to read acurate dB levels :)
Might be a little more complex that it seems, for it to be practical you’re most likely going to need at least some custom hardware to handle the front end level settingY, calibration etc... You might take a look at something like the Audiomatica CLIO system as it’s pretty much what your looking to do. But a DSP library with FIR filters, FFT and some basic math would get you close... Have fun with it...
w2aew Wow, that Sinadder is gold for those that do Rx alignments often. Thanks for explaining all this. I left you a comment (question) on another video about the NanoVNA and characterizing (S11 & S21) a 75 ohm impedance antenna when the Nano's directional coupler's Zo is 50 ohms. Do I need to calibrate the NanoVNA with a 50 to 75 ohm pad and 75 ohm Termination, short and open all with F- connectors in the calibration plane or how to do it and easier or better way? Thanks Alan!
9:22 The Sinadder 3 is really huge compared to the MDO3000...
Hi Alan, Why does the DB scale of the meter show "minus" 12db while in fact we are talking about "plus" 12db?
I wish you would have shown how you were making the adjustments inside of the radio.
That's interesting. I just happen to have a Kenwood TM-231A myself that I bought new in the early 90's or so. The front panel light have all gone out and there is still a bug that causes a reset of the memories sometimes on power up. Maybe I should consider fixing it up.
If I recall correctly, there is a Kenwood Service Bulletin that describes a mod to address the memory issue.
How does the 12 dB SINAD measurement compare to a true RMS S+N/N measurement?
Great video! I am wonder is it possible to buy such a tool today. But is it possible to measure SINAD using oscilloscope with FFT?
It is possible, but would require you to do some processing on the FFT result. In a nutshell, you would compute the total power within your desired measurement BW which will include the main signal, it's harmonics (distortion components) and noise. Then compute the same total power but mathematically remove just the fundamental of the signal, leaving the harmonics and noise). The ratio of these will be SINAD.
Thanks for another great video! Unfortunately it's difficult to find a sinad meter here in the UK now. I'm going to search your videos to see if you have one covering sinad measurements with an oscilloscope.
You should be able to find a Keithley 2015-THD digital multimeter - this has a SINAD measurement function.
@@w2aew Thank-you Alan, I'll have a look. I'm also looking for a reasonably priced LCR meter for QRP and ham projects. I'm building a shopping list!
@@acestudioscouk-Ace-G0ACE Good luck with your search. I have the DE-5000 which works well, but has gotten pricey (over $200 now). Just take care to check the specs on what you get - many very inexpensive LC meters can't measure very low values (inductors in particular) that are often needed in our radio projects.
@@w2aew Thanks Alan, the best price for a used Keithley 2015-THD I found is $796.00 + import duties, so out of this hobbyists budget. I had been looking at the DE5000 and that comes to the UK for about $180, which is do-able. Others have recommended it and your endorsement adds weight to that. Is there a way of measuring SINAD with an oscilloscope? I have an old LeCroy scope.
@@acestudioscouk-Ace-G0ACE You can do the THD part of SINAD - it's just adding the noise component in that is difficult (integrating the noise over a limited BW). I did a video on the THD part...
Thanks for the video! Unfortunately I still don't know how to interpret sensitivity specs when comparing two radios.
What kind of radios specifically? FM VHF/UHF rigs? HF multi-mode rigs?
@@w2aew Yeah FM UHF/VHF.
@@jeffsmith3350 FM VHF/UHF receivers are typically spec'd for sensitivity by listing the minimum signal level required to achieve 12dB SINAD. Sometimes the 12dB SINAD is mentioned, sometimes it is omitted. The minimum signal level that is indicated is the sensitivity spec. For example, the Icom IC-2300H specs the receiver sensitivity at 0.18uV for 12dB SINAD. While the Kenwood D700GA 0.16uV. Thus, the Kenwood is slightly more sensitive since the signal level to achieve 12dB SINAD is slightly lower than the Icom. The Alinco DR-735 specs 0.20uV for 12dB SINAD, making it less sensitive than the Icom and the Kenwood.
@@w2aew Aha, excellent! Thanks so much for taking the time to explain that to me. Now it makes sense.
Do u ever see these for sale
Just wanted to say I have learned alot from you - probably more than from any other UA-cam videos. I don't always understand alot of what you say but I always pick up something. Your knowledge is rather mind numbing . Sorry to hear you lost your father last october. Thanks.
What basic equipment would I need to measure receiver sensitivity of an old (boat anchor) amateur radio receiver?
I would say a signal generator and some attenuators, and your ears! You can also use a simple voltmeter on the audio output to measure received signal level. At the end of the day, when aligning a receiver, you're simply trying to get the best SNR. That can be determined with your ears. If you really want to get the "numbers", then you'll want calibrated signal generator and possibly a way to measure SINAD.
-103dBm equates to 1.583uV for the SSG output, I assume 1.7uV is the instruments actual output?
@-103dBm, the generator shows 1.6uV
Interesting stuff, Alan. Do you have the "modern day" equipment that you can compare it to? It would be interesting to see the differences.
I don't.
The free app baudline and a sound card can do all sorts of audio band spectrum analysis.
@@NiHaoMike64 Looks cool, but sadly no Windoze build.
@@w2aew Maybe worth a try running it with WSL or a Linux VM? I'm not sure what sort of distortion Windows audio processing will introduce.
Hi ElmerFuddGun, I have a SINADDER 3, and have recently owned a SINADDER 5. Both of these were compared against my recently ( 12 months ) calibrated HP 8903A. Both SINADDERS were within 0.5 dB with what the HP measured and these measurements were taken at 2 points, 6dB and 12 dB :-)
I am confused. Shouldn't the SINAD reading be a positive 12 dB not -12 dB?
5:09 - Oops... it says it is a LM388 not LM386. I've never used the LM388 but apparently it is based on the LM386.
Ah, so it does! Oops! You found one of a few verbal errors that I noticed...
Can the sinadder 5 be used in an AM environment like 11 meter radios to do RX alignment or is it fruitless ? Newb asking......
If you use it to measure SNR with a weak signal, and then try to optimize the IF alignment to improve SNR, then yes it can be used.
Could somebody explain how the oscillator and notch filter circuits work? The several feedback paths make it difficult for me to understand by inspection how the overall circuit behaves.
I'll add these to my long list of future video topics.
@@w2aew Thanks!
Does the same procedure apply when using Sinad for am/SSB receiver alignment?
73s
Basically, yes, but there will be minor differences as outlined in the service documentation for the unit.
I'm afraid I'm a hopeless dinosaur. I still tend to default to pounds, ounces, microvolts, and 20dB sig to noise thought on receiver sens. I can remember when .5uv was considered, "pretty fair."
A NOOB assumption at the risk of looking dumb, if my cheap signal gen doesn’t go to -123db could I calculate a simple rf attenuator as shown in one of your previous videos to achieve this. Anyone feel free to educate me. Thank for your experience and hard work
You certainly can build an attenuator, but beware that at these very low power levels, it is very easy to get fooled by leakage from the coax (signal leaking through the coax shield into the air on the "high power" side of the attenuator, and being picked up through the coax on the "low power" side, thus making the actual power level higher than you'd expect on the attenuated side. Double or triple shielded coax helps in this situation, but gets pretty pricey.
Thank you, time to start looking for a better signal generator.
You keep forgetting the minus - it is MINUS 12 db SINAD.
The meter scale is calibrated in the standard audio dB level (0.775Vrms into 600ohms is 0dB), that is why is shows the negative values. However, the SINAD quantity is >1 (Signal+Noise+Distortion divided by Noise+Distortion), this results is a positive SINAD value - so you simply omit the negative sign from the meter scale when reading SINAD.
im going to build a modern day version ill send you one when i am finished
Now, *that* will be interesting!
You are driving me crazy! Availability? Nope. Nowhere.
There’s a very basic model on eBay for $150, but it appears to have minimal features compared to the 3 model.
Seriously.. Thanks for he knowledge!
I don't think I'll every own one of these.