#296

[@ohaya1]

Thoroughly enjoyed this! I think this video should be seen by every ham in training.

[@andrewlit2202]

Alan, just want to thank you for the years of high quality content. I started watching when I was 12 or 13... Now I’m nearly done my degree in EE, and your videos have certainly been a part of keeping me inspired to follow this path. Keep up the good work!

[@Jan_Talcott_100]

What a wonderful job you do explaining this topic. You drawings and notes are excellent!! Thank you.

[@bobkozlarekwa2sqq59]

I’ve been subscribed to your channel for about a year, and I look forward to very new video you release. I also follow a few pages that you follow such as The Radio Shops page and TRX Workbench. I’ve been licensed since 1970 and have remained somewhat radio active throughout that time. Your videos have taught me some troubleshooting tricks and techniques that have resulted in getting me into a restoration mode. In the past when I attended a hamfest I’d avoid radios and test equipment that were in a visible state of disrepair. Now, I look for them, so I can restore them and give new life to an old faithful piece equipment. 90% of the repair process is usually replacing failed capacitors. Just wanted to say thanks for all your hard work!

[@AcctistaZ]

To every viewer of this video (i assume many are students like me), please remember to exclude w2aew from your ad-block list. If you want high quality content such as this, support and give motives to this guy

[@migsvensurfing6310]

What about disabling it completely so YT stays free ...?

[@rabbibacongrease88]

This is one of the best videos I've seen on this subject.

[@lalchandra4590]

This person has amazing teaching quality. I worked hard to understand smith chart from class lecture. But Alan's video help me alot.

[@cbradiomizfit7562]

Yessir i agree

[@rocketryguy]

I just stumbled onto your feed via a google search, and I have to say that at least on this episode you do an excellent job of presenting. This is a distinct skill beyond comprehension of the subject matter (which you obviously also have). Your clear, and most importantly succinct, presentation of this stuff is top notch. Looking forward to seeing what else you've done on your channel.

[@w2aew]

I hope you enjoy my 300+ other videos as much as this one.

[@StefanGeets]

While studying my ham radio exam I got confused about these concepts. Your video brought me clarification. Great! Thank you !

[@MobiusHorizons]

Thanks for the very clear descriptions!

[@paulbaker9277]

As a new ham in VK land with a F licence, thanks for your video, when I can see the process , even though I read the literature, a visualisation helps a lot in seeing it set up as you talk through it.

[@VK2XXL]

So many people think their rigs are only doing like 30 or 40 watts. The old Kenwood hybrids were very conservative with their PEP which is why they sound so good on the air. More people need to see this. 73 from Andrew VK2XXL

[@jeffryblackmon4846]

Every ham can learn something from this video. Many thanks and 73.

[@octavmandru9219]

Absolutely superb explanation, as always. Thank you Alan for enlightening some aspects I was missing before I watched your video

[@paultomasetti5164]

More please! Things like discerning between good and bad modulation envelopes. What makes them bad,what makes them good. I feel that I don’t know exactly where I should be looking. For example, I here the phrase going into compression. Some people will be pointing to the peaks and some,the troughs. Should I be focusing on the very outer edges? Or the very center where the shaded areas are coming together. I hope my confusion isn’t rubbing off on anyone. If you already have more video on this, I’ll find it and you can disregard my question. You’ve definitely made things more clear. Thank you for sharing your knowledge.

[@DonDegidio]

Hi Alan, You have a knack of making these topics easy to understand with the visuals you use. :-) 73 WB3BJU

[@brianwhelan5093]

Hi Alan, what a wonderfully factual, visual and practical video for all (experienced and the not-so-experienced!!) to use to understand a topic that is not too often discussed. A pleasure and so easy to watch as per usual; well done! Brian EI8EJB

[@tommybewick]

Great video, I'm just studying for amateur extra class and on the section of PEP. Great explanation. 73, Tom

[@DennisSantos]

Absolute quality video

[@bobgilliland5095]

Excellent video Allen, as you always do. This video answers that big question as to whether the transceiver is putting out proper power levels, as many of us ask ourselves. I would like also to see the addition of the effects of the transmit ALC influence, particularly in regards to digital modes. I really enjoy your videos. Thanks, Bob K3TCT

[@DavidS-iw4ei]

Thank you I learned something new today. And you reinforced what I was thinking.

[@Orvulum]

Great illustrations!

[@DucatiMTS1200]

Thank you for explaining. Most appreciated. I have been studying your tutorials and building your circuits to help me better understand. I'm having so much fun since I took up amateur radio. Thanks for your precious time and expertise.

[@FineTuneCBShop]

Good video .. I hope that many will pay attention.

[@vencentbauer]

It was a great video iam just learning this stuff i would like to learn how to peak and tune cb radios

[@boxingday11]

Excellent explanation, well explained, thank you. Best regards,Carl .

[@-Todays-Tom-Sawyer-]

Great video as usual Alan. The single tone method using my frequency counter you taught me is how I tune all my SSB boat anchors. I have told many other hams about you and many use that method. Great stuff. I have a Drake W4 watt meter in my shack. I would like to learn more about adding the peak responding circuit you mentioned. 73s KF6HF

[@w2aew]

You might take a look at the PDC-1 - it might be adaptable to the W4: www.hi-rescom.com/html/pdc-1.html One of the reviewers on eham put one in his W4: www.eham.net/reviews/detail/999

[@berndb.5097]

Of course, the Drake W4 Wattmeter is not a low end part, but the conversion which Peter describes here kzbin.info/www/bejne/g6WTcmSehsSoiJI is also valid for this. In any case, I have rebuilt my W4 exactly the same way and it works flawlessly. 73 Bernd

[@AD4MRick]

Excellent explanation and very nice examples. Thanks for the video. R

[@W1RMD]

Excellent demonstration! I love the Icom 706 mkiig. 10 years of excellent service for me.

[@travised]

I appreciate how you explained PEP on this video. Thaks

[@thomasgerstner8391]

Great video as always Alan. Many TNX for the Time you are spending for this Explanation,. 73s Tom DB1IAT

[@carldavis8228]

I like that PTT to control keying and SG input. Simple yet elegant. Need to build one myself. Also, I always relearn something old. Your tidbits add chlorine to my old knowledge pool, which over time has become tainted with algae and needs cleaning out. Thanks!

[@rasherbilbo452]

So glad to see a new video from you. Happy new year!

[@josephriffle124]

Great video. It gives me a better understanding of SSB power, and be able to make proper adjustment(s) on my radio. I continuously use a oscilloscope on the Antenna output to see the envelope.

[@iammrhellohowareyou]

I recently picked up that fancy drawing tablet tech you're using in this video. Took some notes with it on some of your lesson videos earlier too!

[@archtechgr]

100k congrats

[@trevorpeterson8433]

thank you. I now feel better about how my radio is performing lol

[@nickolaosv1397]

Very nice video. Those days i am building an ssb tranceiver and i realised that there arent any videos about that modulation.

[@bommel88]

As usual, a very good video. I really enjoy watching your videos. They help me understand a lot of stuff. Keep it up! 73 de DL6PT

[@user-il4ri3gy2o]

Very good video thanks for sharing the knowledge.

[@billmoran3812]

Excellent video Alan! This shows exactly why so many so-called techs horribly mess up CB radios in the attempt to make them put out more power. I’m a firm believer in using a monitor scope to set the modulation level of a transmitter on AM and SSB. Also, a lot of hams don’t really understand that much of the transmitted signal in an AM station comes from the modulator in the form of audio power. A similar video regarding power measurements for FM and RTTY/ data modes would be good also.

[@w2aew]

FM and RTTY are both constant amplitude modes (both modulate the frequency, not the amplitude), so the RF envelope is constant.

[@johnclarke2997]

Takes me back to broadcast engineering training when I was training to work on the maintenance of broadcast transmitters which ranged from a couple of watts up to 500kw in all broadcast bands. Transmitters tend to have a duty cycle which says for how long a AM transmitter can run 100% modulation before the power amplifier starts to overheat and shutdown, but as the modulation was fairly low and normally music and voice the transmitters seldom if ever go near the duty cycle rating. Many amateur radio transceivers have a duty cycle figure which for a quality transciever will be shown in the manual or the specification.

[@MattEugene]

this helped me understand my cb radio swr/power meter and why it was only showing an average rated reading of less than 10 watts while talking on ssb. it doesn't mean that the radio is not putting out it's full pep, which is reassuring.

[@jorgemaciel9290]

Buenisimo el video bien educativo muy bien explicado y mas tratandose de radios lo felicito hasta me motivo para comprar un osiloscopio para envolverme en reparación de radios hf

[@prepr8725]

excellent content 73 🎉

[@TheDefpom]

Nice explanation and demo, as always.

[@peterb8387]

Excellent video !

[@tormodberg6342]

Nice demo!

[@stompreaper]

This was a brilliant video. More like this please!

[@rolandosalgado1552]

Very good explanation, thanks for share!!

[@MBJanus]

Many thanks for your explanation. A lot of "spécialistes" in France try to let believe the owners that their TX need to be adjusted and I saw one who wrote he can increase the power by modulating more than 100% in AM mode.. with no distorsion aso. This one no more let ask pubicly about this kind of claims.. Thx again, sincerly yours

[@Frisky0563]

I learned a lot there watch this video. I appreciate the video so much I wish you lived near me!

[@athousandprojects]

Good to see a ReMarkable tablet being used - I love mine though just can't write a neatly as you seem to be able to! As always. great video :-)

[@w2aew]

The notes you see are usually the fourth or fifth iteration - or more!

[@russellwillmott5637]

Wish the overmodulated splatter box idiots would learn from this, by far the best explanation of real power vs "bird watts " thanks!

[@MrJef06]

Great video

[@RobertTKlaus]

Very cool, checking for more like this. I got myself a Siglent SDS1202X-E 200 Mhz Digital Oscilloscope for Christmas, I'm already looking at some of the above signal on my IC-706MKIIG. I already had the Nano VNA H4 a year, and I'm making good use of it! 73 W7XLR

[@soothcoder]

I love your diagrams BTW. The ones in this video were especially good but I also mean in general.

[@davidedwards5461]

Just discovered your channel by chance, it's brilliant. Smith charts are awesome. Thank you for all the hard work. GM4GLG

[@ilanyacobi2918]

Beautiful explanation

[@robertcalkjr.8325]

Thanks Alan. Nice lesson as usual!

[@jbravovideos]

Very Professional Sir

[@kevingray707]

Fantastic video. Give us more!!!

[@cbradiomizfit7562]

Another perfect video I've been looking for. 👍👍👍👍❤❤

[@emylrmm]

Very nicely done!

[@rickvia8435]

Very good, presentation.

[@radiostuff1026]

Very very good video. Thank you. !!

[@legionaire4017]

I really liked this video, thank you for sharing! Are you using just a 10x probe in this example? I'm just curious about what's necessary for input protection. I'd also like to see your explanation of bessel functions in FM modulation, not sure if that is something you'd take the time to create as it certainly would take some effort but I think I speak for most of your viewers here on KZbin, you are an asset to the electronics and amateur radio communities and we are very grateful for your hard work in making these excellent videos!

[@w2aew]

Have you seen my video that discusses FM deviation measurements using Bessel Null? kzbin.info/www/bejne/bnqlgIylfrtoo5o ...and yes, I was using a 10x probe. You'll have to check your probe's ratings to be sure of the safe operating area.

[@andrewferg8737]

Thanks for the education! Great video as always.

[@Diki58]

Hello Aln, you said : "A peak-reading Bird (or other quality meter) can certainly be used to measure the peak envelope power of an AM signal. PEP can be as high as 4x the dead-key power (for a properly setup 100% modulation." The simplest way to visually measure the modulation power levels in AM/FM/SSB is to use a DIGITAL SWR METER capable of being configured either in "Average power", either in "Peak power ('PEAK'), either in “Direct Power”, either in "Power Before Modulation”. For example, the MFJ 826B DIGITAL TOS-WATT METER allows you to measure these different types of “power”. Do you agree ? Sincerely

[@w2aew]

A meter designed for peak reading should work well.

[@renosgarage7451]

clears a lot up, thanks

[@PapasDino]

Thanks Alan, nice explanation of what can be confusing for a lot of us! 73 - Dino KL0S

[@timka880057]

Enjoyed the video! Understandable, you said effective and it reminds me of the root mean squared of AC. effective value of AC.( .707 times the peak or 1.414 the rms) If the meter was quick enough to read it in real time it would be accurate. RF carrier is fast according to what frequency it's tuned to. The lower signal which modulates or rides on the carrier.... I imagine it has an effect on the carrier... like harmonics ( I play guitar so I know about harmonics)..... But both average out mathematically, (I'm sure there is a formula!!!) If it all was converted to DC with a rectifier it'd be double on the top reading on the scope right? Or eliminated to one half the signal on top. And if a L or pi filter, an inductor in series with one or two capacitors to ground, (a resonant filter tuned for that frequency) the carrier would be eliminated. Right? I've been watching you for a while. I enjoy your channel.

[@eddyane67]

Great video! Thanks

[@wa4aos]

Hi Alan, Always enjoy your well explained videos. Bob Allison, the test engineer for the ARRL came out with a book a few years back titled, "Amateur Radio Transceiver Performance Testing;" I suspect you have seen it. Some videos covering more detailed rx alignment and procedures would be great. 73, Glenn WA4AOS

[@w2aew]

I've got Bob's book. Good idea to produce some videos using these procedures.

[@electronic7979]

Useful video 👍

[@ElmerFuddGun]

Interesting how the IC-706 power output meter jumps around with AM (10:05) and two tone SSB (11:00) and isn't constant like the Bird meter. That can add to the frustration when you can't trust the meter. Not just the 706 of course.

[@josephheasley3280]

Great video , well explained. Thanks. GI4GID Belfast Ireland

[@robsonicam]

Very interesting !

[@vidasvv]

Another great video, TNX fr the upload! 73 N8AUM

[@p0k7lm]

Thanks 4 Video !🆒📡📐📚📗

[@assistenciatecnicaemmicrof8817]

Is very Good video , 73

[@ferny107fg]

Thank you!!

[@MrFittyTucker]

Great video as always but I would like to see a video better explaining how these CBer's are taking a hundred watt AM carrier and reading 400 watts on their peak meters claiming that is the actual output power when the transistors aren't even rated any where near that by the manufacturer! At best you could expect maybe 10% more power because they were under rated to begin with!

[@mel-ve3ojn319]

Very informative and a really good refresher, thanks for what you do. 73 Mel VE3OJN

[@earleclemans4836]

Awesome channel 👍

[@antoniodias2776]

Excelente.

[@AcctistaZ]

This is useful for optical communications as well in some parts.

[@robingist6666]

Hi Alan -- K4VU here. big fan (i binge watch your videos late at night). any chance you might be able to do a video on push-pull amp design and theory?

[@johnblake4503]

Another interesting video thank you, can I ask how do you connect your scope to the output of your transmitter, would this likely effect the SWR / impedance seen by the transceiver ? In one of your videos you spoke about not connecting the output of your transmitter directly into your scope, on this video I am guessing this is what you were doing as you were seeing 200v 100w. Many thanks.

[@w2aew]

I was definitely NOT connecting the RF output directly to the scope. If you look carefully at the image at the 7:00 mark, you can see what I'm doing. The transmitter is connected to the input of the Bird wattmeter. The output of the wattmeter goes into a Tee connector. One side of the Tee is connected to another piece of coax that runs down to my dummy load (under the bench, out of view). The other end of the Tee has an adapter that accepts the 10x oscilloscope probe, and the probe is connected to the scope. i describe this over the next minute or so in the video. At 7:50, I zoom in a little more and you can see the probe adapter more clearly.

[@W4BTK]

Alan, awesome pre-COVID video Sir. I want to run the two-tone test in one of my radios but I wonder what each tone should be set in each generator in my service monitor. I was thinking one tone at 500hz and the other at perhaps 1200hz. I use 1000hz when performing single tone (AM modulation adjustment). Thanks!

[@andrewferg8737]

Question: How do you get a 100V envelope when Vcc is just 12V ? Is that accomplished using a step-up transformer?

[@w2aew]

Essentially yes.

[@ornithopterindia]

👍Thank you sir.

[@pd1jdw630]

Good explanation. Thank you. Could you maybe do a video on the Weathstone Bridge regenerative receiver? As build by N1BYT? I can’t seems to grasp how this actually works. I’ve build it, it works. But I’m still a bit baffled about how.

[@gordonwedman3179]

Hi Alan. Thanks again for another great video. I have just started reading the section on PEP and ERP in the new ARRL handbook so this will undoubtedly make things clearer. Gong to try and read through the whole book over the winter☺️. What would you recommend for a scope adaptor? I actually have a 706 Mk2G sitting on my bench that I am going to install in my Land Rover, mainly for VHF but will also try HF. I might try repeating some of your video. Thanks again.

[@w2aew]

I have a few videos on RF Samplers that you might want to review.

[@gordonwedman3179]

@@w2aew thanks. I will carry out a search.

[@Willam_J]

Gordon Wedman - If you want to buy one, instead of build one, here’s one that I can recommend. I needed an extra one, for my field kit, and this one works very well. Building it is half of the fun, but when it comes to test equipment, buying a proven design is the best decision, unless you can test and verify the accuracy of your own build. www.ebay.com/itm/RF-Sampler-1-50-MHz-Modulation-monitor-See-your-signal-SSB-CW-AM-FM-Data/162200390778?hash=item25c3e58c7a:g:~msAAOSwZQxW2M8~

[@gordonwedman3179]

@@Willam_J Hi William and thanks for the recommendation. I have put that on my eBay watch list. Always good to know someone else has tried something and found it to work before buying. Cheers.

[@johnbigbooty]

Very nice Job Alan, especially on the two tone explanation on SSB. Q: Should we use 700/1900 Hz for the two tones? If not, what are the most common?

[@w2aew]

The actual tone frequencies isn’t terribly important. Just be sure to adjust them for equal modulated amplitude (crossing points in RF envelope should be very sharp).

[@JeffLeites]

Great video. I would have been interested in seeing the watt meter responding to your voice in AM mode. K3OHU

[@tonyalmeda8220]

Hi Alan, thanks for this video at a perfect time for me as I'm trying to align SSB on a radio of mine. Can I ask, is the mic gain on your radio at maximum for this two-tone demonstration? I presume I should I have the mic gain at maximum whenever following an SSB alignment procedure? On the radio I am working on I get the SSB RF envelope pattern as shown in your video, but only with the mic gain on my radio turned barely a quarter of a turn. From this I have assumed the radio has been previously set up with too much gain and I need to back it off to show the two-tone RF envelope at mic maximum - would that be correct? The service manual states 30mV for both tones, which I've set, but i presume that if I lowered the level of each tone I'd be able to get the RF envelope pattern where I want it at maximum mic gain - but then I guess the audio output from the mic over SSB would be too low? Just a bit confused right now. I'm using a Marconi 2955B for the two-tone signal and wattmeter and separate 100MHz scope .

[@w2aew]

The audio and mic gain settings should be set such that the ALC is just barely starting to show deflection. You also need to be sure to adjust the levels of each tone so that they result in the same modulation level (sometimes the frequency response isn't flat in the audio path, so the levels have to be set independently).

[@tonyalmeda8220]

@@w2aew Ah! Got it - thanks.

[@stephanc7192]

Very interesting

[@geckoproductions4128]

Hi Alan. GREAT video and explanation. I would like to duplicate your setup to help me retain what I just learned. Could you offer some detail on your RF tap off the back side of the watt meter to the scope? Thanks 73 N5RXP

[@w2aew]

I'm simply using a BNC-tee and a BNC to probe-tip adapter, similar to this: www.amazon.com/Cal-Test-Electronics-CT3655-Oscilloscope/dp/B009QBSKE2 You have to be sure that this fits your particular 10x probe. If you don't care about it being "calibrated", then you can use any number of methods to sample the RF. I have a few videos on RF Samplers that you might find interesting. These will allow you to get the signal to the scope easily. You could then do a simple calibration on your own (measure CW power and then calculate the response on the scope to arrive at an effective RF volts/division).

[@azav8raa]

Alan, thanks for another awesome video. I had fun replicating the demo in the shack and discovered some interesting two-tone envelopes on one of my rigs. Do you have a reference of how to diagnose distortion seen in the two-tone SSB envelope output? Thanks again. -Andy KB7ZUT

[@w2aew]

No additional references at this time. Make sure to adjust the tone amplitudes for equal modulated response.

[@combatwombat71]

Hi Alan, to make an real (actual) power measurement I assume I'd need to couple the 'scope directly to my RF, and not via some sort of pickup system eg. unused port on transmatch. Or if I did use some form of RF 'sniffer' method, how could it be calibrated? Tnx de Rob.

[@w2aew]

You can calibrate a 'sniffer' by putting a constant output signal (key down, unmodulated carrier, etc.) into a dummy load and measure it with a good power meter. Then you'll know how big the signal is on your scope for that power level. Of course, the scope measures volts, not watts, so the power reading won't be linear on the scope. A signal that is half the size (vertically) is actually 1/4 the power, etc. Remember too that the 'sniffer' response will most certainly be frequency dependent - so a calibration done on 20m won't hold true for 40m, etc.