TSP

[@MrCarlsonsLab]

Thanks for the video, and the kind mention too Shahriar!

[@stevefriedl3983]

The second unit from the left is an HP 537A, which covers 3.7 - 12.4 GHz and was introduced in 1966. Keysight still sells this unit - still the "A" model! - 55 years later, for $5923. What an amazing legacy of quality

[@AppliedScience]

I always wondered how those things worked. Thanks for the video!

[@Thesignalpath]

Anytime my friend. I hope all is well with you.

[@w2aew]

These mechanical frequency meters are things of beauty. Would've been fun to see you replace the DMM with a analog VOM like an old Simpson 260 ;-)

[@RideGasGas]

I used to use these all the time when doing alignments on cryogenically cooled paramps for an earth station while in the Army back in the 70s.

[@xDevscom_EE]

Yay, vintage RF! Looks like lab got new layout with shelves. Time for the lab tour, perhaps?

[@Thesignalpath]

The 10-year anniversary of the channel is coming up! I'll do special video with a tour. :)

[@bfx8185]

@@Thesignalpath Looking forward for that special ;)

[@DoctorThe113]

@@Thesignalpath YES! Looking forward to it!

[@_..---]

The sensitivity of these devices is amazing, cool video man.

[@andye2005]

Brings back a few memories.. I started my electronics career in the Radar industry, about 1976 . There were a few test setup's with that type of device bolted to the waveguide. Another interesting item was a calibrated trough line, where you could measure the frequency, forward and reflected power., Used when building the scanners. At that time I think there was only one spectrum / network analyser in the factory , and they cost several times the value of the average house! Andy

[@SeanBZA]

And the RF dummy load waveguide, a large tapered section of waveguide filled with an iron oxide loaded epoxy. New ones would always smoke for a few minutes as they burnt off all the paint. Same for the RF absorbent chamber, where the black carbon foam would smoke as well, till it had burnt out the plastic used to make the foam. Then it was brittle, but lasted till it either crumbled from touch, or just collapsed from age.

[@physiqueDrummond]

@11m43 Shahriar in a gleefull voice: 'Check this out!' I almost heard Dave's "Aah... its better than sex on a stick" :)

[@PixelSchnitzel]

Wow, you're a mind reader! I've been getting increasingly curious about these for months, but have found very little about them. THANKS!!!

[@vincei4252]

Nice to see awesome vintage HP gear on the channel. Thanks!

[@2013Drama]

I have one of these 536A's , a bit rougher condition but I can attest it is beautifully made and is also nearly perfect in calibration even after all these years. Thank you for doing a good experiment on it!

[@xyzconceptsYT]

Just gorgeous RF engineering, love it.

[@erikisberg3886]

Brings memories back for me. Used these with the old HP sweepers for microwave work in the 80:s. I still have the X band version and Ka band versions on my shelf.

[@bitrot42]

Astounding! I had no idea they were dealing with such high frequencies back then, and that such high precision would be possible with mechanical gear. Thanks so much for sharing!

[@CraigPetersen12f36b]

I have seen these on eBay from time to time but but wasn't sure exactly how they worked. I figured the unit produced some sort of peak or null at the target frequency. Now I need one, thanks for another great video!

[@vidasvv]

It's AMAZING on the accuracy achieved with a mechanical device ! TNX 4 yet another great video ! 73 N8AUM

[@BruceNitroxpro]

vidas v , True enough, but nicely shown in 13 digit accuracy. ROFL de KQ2E

[@rickdabney5082]

I used these on my bench at HP way back when. But I prefer a “classic” moniker rather than vintage. :-) Quick story. One of the less-than-stellar engineers told us that to check the vibration tolerance of the then-new 86290 module, we were to drop a particular model frequency meter onto our bench from a height of one inch. So a few times a day, thumps were heard, indicating the test was in progress. We still used the same frequency meter for some additional tests. I guess it says something about the robustness of the equipment back in the day.

[@BruceNitroxpro]

Rick Dabney , Kind of sums up the spirit of the day. LOL I was not in that frequency domain at the time! I was topping out at 150 MHz. LOL

[@FFWrench]

Tickled to see you do a video on these! I have a 536A at home. It was part of my tools for working on a radar in the military (just recently started retiring this radar). Being I didn't have a Spectrum Analyzer I was never able to use it. I picked on up at the Dayton Hamfest in 2012 for $10. Wish I would have grabbed the 537 too....

[@S1naFa]

همیشه یک سورپرایز خوب تو این کانال هست، ممنون شهریار برای این همه دانشی که بهمون میدی

[@waynethompson8416]

I remember seeing these at a company I worked for years ago. It was during the 1970's and while I never worked with them myself, I was always amazed by them.

[@joopterwijn]

Amazing stuff! Never seen these before.

[@gymprofessor329]

Seems like finding those dips would be really nice with an analog voltmeter. Sometimes having the physical needle is really nice for peaking things.

[@BruceNitroxpro]

Gyn Professor , Sounds like a comment by Paul Carlson of Mr Carlson's Lab. LOL

[@jeremiahrex]

Used these at university around 2005, they feel really nice to use. Instruments from that era were part of what got me interested in RF. Kinda funny how they updated the design language for some of them over the years but the mechanisms stayed basically the same.

[@lazyman114]

Super cool stuff and I can actually understand everything that's going on compared to some of your other videos.

[@glasslinger]

I was using one of these and thought it wasn't working. It was the very sharp dip! It is very easy to skip right over the dip if you don't have any idea what the frequency is. Something that would have been interesting would be to tune it to the second harmonic when it was on the network analyzer to see how much the harmonic dip is attenuated. (and the third harmonic to see if even-odd is different)

[@diegogmx2000]

it's really enlightening to see the operation of old devices, it broadens your perspective, sometimes there are solutions we don't even consider now a days due to the cheap availability of fast electronics yet for some problems having these simple devices in mind can be really useful

[@nikmilosevic1696]

Managed to get a 536A at a deceased estate sale, I wasnt familiar with it but its was so well made I had to grab it and have a play. Glad I did, such a cool old piece of equipment, I was also surprised how accurate it was.

[@Skinkworks42]

Attach a servo to the knob to make a teaching demo spectrum analyzer that clearly shows the frequency sweep behavior

[@funkyironman69]

Great video, I had seen these but never understood how they worked or how to use them.

[@garynichols1502]

Great video, I just bought a 536A 3 or 4 weeks ago. Great instrument.

[@JonnyDeRico]

It is like magic, because rf is magic :D

[@Alexander_Sannikov]

That is very cool, but on diagrams it's unclear what's dielectric, what's a conductor and what's empty space. Still wish you took one apart to see.

[@witeshade]

I'm imaging a paper spectrum analyzer with a motor set to slowly rotate the knob and a seismograph style pencil on an arm to record the deflection. Honesly probably wouldn't even be hard to make.

[@jimomertz]

These units were probably designed using slide rules and pencil and paper. It amazes me they could achieve that kind of accuracy.

[@cda32]

have you tried building one of those ham radio style plumbing fitting cavity filters? would be cool to see that on a VNA

[@BruceNitroxpro]

Colin Alston , So, show them what a ham can do! LOL de KQ2E

[@CisterJr]

is it possible to detect even modulated signals with this? Like: if i want to check what is the WLAN signal frequency of my router, it will work? fantastic job!!

[@NIOC630]

Thank you very much, i have the 12GHz variant of this thing and some day i would have taken it apart if it wasnt for your explanation!

[@artej11]

Thanks for showing those, only read about them in books :) I have came across RF absorption detectors though (measure RF power by heat generated/rise of temperature); maybe you could try to couple one to your cavity to have the most low tech frequency meter :)

[@ironfeatherstudio4476]

Great vid. Thanks

[@supernumex]

Awesome video! I would really enjoy a look at the "mid-range" USB VNA's. such as the pico vna

[@rogerlafrance6355]

There's nothing like pure physical measurement. Besides the cavity wavemeter, slotted lines and calibrated delay lines work much the same way. You measure it with a ruler and calculate.

[@vincei4252]

That was very interesting, thanks for posting it!

[@chialor1945]

Funny, I just calibrated one of those Siglent SVA 1032X lol. Let me know if you need any accredited calibrations, ANAB.

[@PeregrineBF]

It's nice to see cheaper equipment used for the experiments! Siglent is a lot more affordable for this stuff than Keysight or Tek.

[@harbselectronicslab3551]

I still have a full set as well.........I also have a full set of HP slotted lines.......yep I am an RF geek lol

[@trevorvanbremen4718]

... and if ya get desperate enough, you could always make a rather large coffee mug (with a small leak) from a 'broken' unit!

[@benmodel5745]

Very cool. I suppose these were used with analog meters back then. Whenever I measure larger diameters with calipers (8-24") watching the needle as you sweep it across it is just a bit easier to find the peak. Had to explain to my co-worker who hadn't spent much time in a machine shop that yes, I have a pair of digital Mitutoyo calipers, no I wouldn't prefer to use them over my B&S dial calipers.

[@PeregrineBF]

Digital is faster for absolute measurements. Analog is faster for the first derivative. So finding the peak is easier with analog, reading the true value easier with digital. Though with a fast enough update rate (60Hz or better) and appropriate output display (eg bar graph, oscilloscope-style trace line, etc) a digital display can serve just as well as an analog one for easy first derivative estimation. But even very good calipers don't have that capability, so I'll also keep my dial calipers handy!

[@bobvincent5921]

Thanks. Can the physical dimensions of the cavity be applied to the other measurements methods you used eg the diode??

[@SoddingaboutSi]

Just bought a Model 536A this evening on ebay. Coincidence?

[@vincei4252]

hahaha. Beat you to it. I bought two different models ;)

[@Kilohercas]

If we put stepper on it, and synchronize reading with high resolution ADC , how good spectrum analyzer we can make ?

[@Thesignalpath]

Not a very good one, specially if the signal is complex and broadband.

[@derkeksinator17]

Would have been interesting to reduce the span/res BW on the VNA to take a closer look at the dip. Looks beautiful though.

[@snower13]

What's the name of the other channel @18s? Mr Costas Lab?

[@SoddingaboutSi]

I need to calibrate mine. I can only run to 1.3Gig but at that frequency, it's out.

[@ogitakasi3030]

Really neato!!!!

[@vejymonsta3006]

50 dollars for similar meters on ebay. That is incredible value.

[@BruceNitroxpro]

VejyMonsta , And, could save about $5,000 !

[@scottvance74]

The high q of these devices makes them suitable for conversion to a resonance cavity for measuring the dielectric constants of materials. It feels sad destroying a piece of finely machined history, but the new resonance cavity measurement devices sometimes cost 5-10K and one can make a reasonable measurement device for under $50 using this method.

[@DrFrank-xj9bc]

Magic

[@gustavlicht9620]

To be honest, unless a device was subject to misuse or abuse, calibration is mostly a matter of ensuring quality, traceability and liability reduction. These are very important reasons, and calibration can detect equipment damage, abuse or misuse, but equipment performing well without calibration is not that surprising. It should be the norm, calibration is to catch the expensive exceptions.

[@jimmycrider8677]

I used them in the Air Force on radar from F-111 air plane

[@jangoofy]

16:43 - did the specs not say "at least 1 dB" (07:48) ? so it could be more, and is.

[@Thesignalpath]

Yes, that is guaranteed performance. They often exceed that without issues.

[@TunioMir]

Take it apart!

[@SimonCas]

Do you need an apprentice? I would love to learn from you

[@arts9591]

I need to learn how to set up a signal generator using very basic “how to” information - thanks

[@stargazer7644]

You set the desired frequency, and the desired output level. Optionally, configure the desired modulation. That’s about as basic as it gets.

[@hateercenor]

Rotate the Page View Do one of the following to rotate the view of the document pages: Go to View > Rotate View > Rotate Right or Rotate Left. Clickin the Common Tools toolbar > choose Rotate Leftor Rotate Right . Right-click the document, and choose Rotate Right or Rotate Left. (In macOS) Move two fingers around each other with Mac trackpad. Note: Foxit Reader allows you to rotate pages in 90-degree increments. Pages are rotated for viewing purposes only, and no changes to page orientation will be saved to the PDF file. help.foxitsoftware.com/manuals/pdf-reader/foxit-reader-for-mac/en-us/3.2.0/View_PDF_Files.html

[@TeslaTales59]

No visit from Pooch?

[@Thesignalpath]

He was there. Watching from above! :)

[@sefarkas0]

What is the top cavity used for?

[@SeanBZA]

Nothing, it is the spare volume. It does though need to be made very lossy, so that it does not interact with the measuring chamber. Tthe piston varies the volume of the lower chamber, and as the frequency lowers the top chamber gets smaller till at the end stop it is almost non existent. Piston does need to have a very good RF ground, so there is a very tight tolerance, plus a few sets of RF fingers, that are on the outside of the piston that ride on the wall, to get a good RF connection. Heavy silver plate on both parts inside the cavity, polished and ground during manufacture to get a very close tolerance cylinder diameter inside in the silver coat, and same for the piston, so it has only a few gas molecules of clearance between the two. There is probably $50 of silver in the instrument as plating. Then the cavity is sealed with a good air seal and purged with nitrogen, to keep the cavity from oxidising, and there is a pressure compensating bladder to allow temperature and altitude changes as well.

[@stargazer7644]

@@SeanBZA maybe not $50. I could plate your entire car with 2oz of silver. Putting that much plating on it would wreck your very careful machined tolerances.

[@SeanBZA]

@@stargazer7644 Machine after plating, to get the tight tolerances. you will polish off a part of the plating, because in most cases plating is not always totally even, especially with complex shapes.

[@Hmmmm323]

☀️⚡💚⚡☀️

[@MrJosiahCochran]

Can you do a video on the nano vna V2?

[@matthiaszeitler8317]

This video is amazing. This shows where our future is going wrong. What engineers developed in early times is realy unbeleivable to me . My brain is to weak. Does such developments only occure when world is in danger like cold war?

[@octavmandru9219]

Amazing! I feel people were more innovative having less means, back then. Now we are cuddled

[@zyxwvutsrqponmlkh]

lelz I got some of those

[@t1d100]

Sometimes older tech is better for a particular use... Like Analog/CRT oscilloscopes are better for viewing curve traces than a digital scope... So, what applications would this unit be better for than a modern digital unit?

[@adamsonlinearrayspeakersha87]

Hello

[@leozendo3500]

So it's just a big screw

[@WillArtie]

Mazing!!

[@niadebesis565]

At work se have a ton of these detectors that se are going to throw away of gift em at locale universitys

[@the_jcbone]

Hm. It's really irritating to listen to facts about HP Equipment without the heavy french-canadian accent. 😀

[@Thesignalpath]

I am sorry. I misunderstood you.

[@robbowman8770]

I have watched TSP from the start and loved it, but I'm sorry to say it's lost its charm for me ... since July 2019 output has averaged only about 13 minutes per week, and is therefore necessarily more shallow than before.

[@larryl730]

No worries, I'll keep the love going.