Microwave plumbing - Page 1
Forum section: electronics / testgear

author: Bud
author_rank: Super Contributor
timestamp: May 28, 2014, 02:49:40 am
content: I guess it is easy for a microwave engineer to become a plumber once retired - would already know how to bend, cut, cap and solder copper tubing, and use a torch wrench.Some pics of the guts of an HP 85047a 6GHz S-parameter Test Set. If you have your pics of insane microwave plumbing please post them here!

author: IanB
author_rank: Super Contributor
timestamp: May 28, 2014, 03:12:50 am
content: Er...where's the actual guts? Why is it an empty box?

author: c4757p
author_rank: Super Contributor
timestamp: May 28, 2014, 03:19:16 am
content: Quote from: IanB on May 28, 2014, 03:12:50 amI think it's all there. Looks like it's meant to go on the bottom of a network analyzer, so it's big so that it fits underneath properly.

author: Bud
author_rank: Super Contributor
timestamp: May 28, 2014, 03:25:24 am
content: That is right, the VNA is placed on top of the Test Set, therefore they have to have the same profile dimensions. All you see in the pics is all of the insides of the Test Set.

author: FrankenPC
author_rank: Unknown
timestamp: May 28, 2014, 03:27:00 am
content: A few shots of my Tektronix 7S12. Only only up to 1.8GHz but sure packs a lot of spaghetti into a tiny little space.

author: JonnyBoats
author_rank: Regular Contributor
timestamp: May 28, 2014, 03:36:16 am
content: > If you have your pics of insane microwave plumbing please post them here!Does this count? There is microwave waveguide going to the top of the mast. I had a friend in the shipyard whose job was to weld up all of this plumbing. He once took me to the very top of the mast while one of these ships was still in the shipyard under construction.Sorry I don't have a better photo. (Or perhaps I do, but then I would have to kill you ;-)

author: corrado33
author_rank: Frequent Contributor
timestamp: May 28, 2014, 03:37:49 am
content: If you've ever worked with that small 1/8in tubing, you know those are works or art. It's pretty hard to make the bends perfect enough to reach both places without a bit of... persuasion.With that said, the tubing was probably bent by a machine would be my guess.

author: vk6zgo
author_rank: Super Contributor
timestamp: May 28, 2014, 05:57:42 am
content: It's not what we would normally refer to as "microwave plumbing"---it's just rigid coax.Try this link for a good picture of real microwave plumbing.http://www.efda.org/2010/01/week-14-waveguides-and-divertor-plates-removed/

author: VK5RC
author_rank: Unknown
timestamp: May 28, 2014, 09:35:40 am
content: I like the comment I read about waveguide, built with a micrometer, tuned with a hammer. :-)My first feedhorn needed quitea bit of 'tuning'!

author: jpb
author_rank: Super Contributor
timestamp: May 28, 2014, 10:35:41 am
content: Nice to see inside part of an 8510. My first graduate job was at GEC Research working on Microwave ICs and the labs bought an 8510 when it first came out. The cost was astronomical (fifteen or more times the price of my flat (apartment for those in the US)) getting on 60 times my annual salary!One of my jobs was using the 8510 attached via semi-rigid to a small gold-plated jig in which devices mounted in holes on ceramic squares mounted on brass blocks were measured. It felt almost ceremonious with all the ritual of doing a calibration first, cleaning the contacts with IPA, making sure to use a torque wrench to attach the sma connectors to the jig and so on.

author: Bud
author_rank: Super Contributor
timestamp: June 26, 2014, 04:04:20 am
content: RF section of a HP 8565a 22GHz spectrum analyzer

author: VK5RC
author_rank: Unknown
timestamp: June 26, 2014, 11:39:37 am
content: @Bud , what great pictures, I love the detail including the labelling of test ports etc stamped into the shield/covers, also the use of 'real' parts so if something dies you have a hope of fixing it.

author: edavid
author_rank: Super Contributor
timestamp: June 26, 2014, 02:04:32 pm
content: Quote from: FrankenPC on May 28, 2014, 03:27:00 amI think you mean 7L12...

author: SL4P
author_rank: Super Contributor
timestamp: June 26, 2014, 02:19:11 pm
content: If you ever get the chance - go visit a TV transmitter hall.That's real plumbing - and get the guys to show photos when a waveguide is dented or a bird has managed to get into the pipe. (I the 500kW left anything of the tubing!)Generally I stay away from those rooms - as there is a lot that can change your personal future inside them - but the guys trained in high power RF seem to have families (well most of them).

author: Richard Crowley
author_rank: Super Contributor
timestamp: June 26, 2014, 03:19:53 pm
content: Quote from: SL4P on June 26, 2014, 02:19:11 pmOr you could just view the video of Dave touring a broadcast TV transmitter site here....http://www.eevblog.com/2014/01/17/eevblog-569-tour-of-an-analog-tv-transmission-facility/In more modern high-power RF installations, you will see more flexible waveguide vs. the rigid rectangular waveguide in the video.

author: echen1024
author_rank: Super Contributor
timestamp: June 26, 2014, 03:20:42 pm
content: Quote from: SL4P on June 26, 2014, 02:19:11 pmLike the Test equipment of our dreams?

author: unicornio
author_rank: Contributor
timestamp: June 28, 2014, 12:26:45 am
content: Here I have some microwave stuff that I'll have to someday put up for sale on ebay...

author: slurry
author_rank: Regular Contributor
timestamp: December 20, 2016, 04:23:34 pm
content: Enjoy this rats-nest of phasing network for the antenna array of a glideslope transmitter.The GP transmitter, which is commonly used at airports, emits a glideslope to guide airplanes down in an angle of 3º for a comfortable landing,the silver tubes are line-strechers, one for each antenna and the silver-spaghetti-things with four connectors are 90º hybrids.

author: slurry
author_rank: Regular Contributor
timestamp: December 25, 2016, 10:51:12 pm
content: A few more, first an 1GHz power amplifier, puts out a few hundred watts of power (pulse),also my new directional coupler, covers 300MHz to 3GHz

author: cdev
author_rank: Super Contributor
timestamp: December 25, 2016, 11:13:09 pm
content: Adam is a ham in Croatiawho has a blogthat has lots of pretty pictures of his adventures modifying for ham use and building his own UHF hardware.It often really is pretty, I agree. Form and function merged beautifully.

author: tautech
author_rank: Super Contributor
timestamp: December 26, 2016, 02:45:15 am
content: A pic that Dave put on Flickr of the mobo of a Siglent Spectrum Analyser with the RF black magic traces and filters showing:https://www.flickr.com/photos/eevblog/27749729501/Further explanation in Dave's teardown vid:https://www.eevblog.com/2016/06/22/eevblog-892-siglent-ssa3021x-spectrum-analyser-teardown/

author: VK5RC
author_rank: Unknown
timestamp: December 26, 2016, 05:14:10 am
content: Some include 1296MHz in the 'microwave', below is a bit of home patched together modules.IF rig is an Icom 910H (6-8W) then a Down East Microwave amp (20W) -into the splitter (green PCB on the RHS) then into 2 PA modules (W6PQL's - thanks) each with 2x XRF-286 PA transistors - combiner on the LHS - into heliax - produces about 320W out at 1296MHz.The heat sinks of the main PAs (you can see one of the PCBs standing vertically) face in toward each other and the fan in the middle keeps both the heatsinks and the combiner cool. The easily seen fan on RHS is for cooling the DEM 'pre-amp'.Sequencer is a MiniKits, everything together draws about 30- 40A at 28V. I kept blowing the brains out of the PHEMT pre-amp.Currently it is having a little holiday!

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: December 26, 2016, 05:37:05 am
content: Here's the cavity oscillator inside my Tektronix 1L30 spectrum analyzer plugin. It goes from about 1.1 to 2.5GHz, something like that. It's tuned mechanically, by moving plungers in and out. The plungers connect to pistons inside the cavity, making two cavities that change in volume. I don't know how it works, but there's a triode inside configured as a grounded grid amplifier, the two cavities being on the cathode and plate side, with coupling between the two sections provided by two wire loops.I suppose it's something like a transformer with a capacitor across each winding, which somehow magically provides coupling to maintain oscillation and high enough Q LC circuit to maintain a +- accurate frequency.In the 1L30 it is locked to a crystal so it doesn't drift.This is an old picture, and I don't feel like taking the thing apart again, it's tricky stuff getting the parts to slide nicely again.

author: bncengr
author_rank: Newbie
timestamp: December 27, 2016, 09:30:38 pm
content: Found this contraption in a shed...

author: Emo
author_rank: Regular Contributor
timestamp: December 27, 2016, 10:24:19 pm
content: Just a small (40 kW) DVB station

author: radar_macgyver
author_rank: Frequent Contributor
timestamp: December 27, 2016, 10:52:04 pm
content: First picture is of a 2-channel microwave transceiver for a radar system. The enclosure wasn't finished when that pic was taken (note the empty holes for many of the connectors). Stack of plates in the middle are, top to bottom, RX, LO and TX. The one on the right wall is the built in calibration system. The left two boxes are second stage frequency converters.Second one is a radar transmitter in a test setup, running into dummy loads. You can see the WR-284 waveguide hardware, what I would typically refer to as 'plumbing'. Second cabinet from the left is where most of the PAs are, you can see the two power combiner network to combine power from four 3.5 kW modules.

author: bsalai
author_rank: Regular Contributor
timestamp: January 08, 2017, 10:25:25 pm
content: Quote from: SL4P on June 26, 2014, 02:19:11 pmSent from my iPhone using Tapatalk

author: slurry
author_rank: Regular Contributor
timestamp: January 19, 2017, 08:56:38 pm
content: Not very much plumbing, more like HF mechanics..I repaired this coaxial relay tonight and it works just fine now