HP 8508A Vector Voltmeter Overview

In this video, I'm joined by my mate Miguel to have a look at the precursor to the modern VNA, the 8508A Vector Voltmeter and a general chat while doing so. Miguel is an old Navy guy so I cut out as much of the salty language as I could so I hope you enjoy this. I'll be following up on this video with a talk about cal labs I did with him soon.

[@Tracks777]

lovely content

[@tgsoapbox]

Thanks.

[@bloodyl_uk]

Great to see a new video from you tg, it's been a while. 😎

[@tgsoapbox]

Thanks appreciate it.

[@PixelSchnitzel]

WOO HOO! Another tgsoapbox video! I don't recall an analog vector voltmeter episode. Can't find it in the back catalog. Which one was that? My beverage of choice this morning is coffee from a K-cup with a splash of half & half. :-)

[@PixelSchnitzel]

Never mind. Found it! "HP 8405A Vector Voltmeter Partial Repair", 8/20/2017

[@tgsoapbox]

Thanks - Glad you like the videos.

[@DrFrank-xj9bc]

When I read the title first, I thought it's about the FLUKE 8508A.. but that's much more interesting!

[@tgsoapbox]

Thanks - Strange that they ended up with the same number.

[@davidv1289]

Interesting Video! I used vector voltmeters in the field for cutting and checking transmission lines on monopulse beacon radar systems. They use phase difference to determine if an aircraft is left or right of boresight so the electrical length of the cables is critical. They are excellent for this application as the cable can be trimmed while connected and results seen immediately. Do you know of a AM/FM test source that matches (or comes close to) the HP 11715A? I want to run the performance tests on an HP 8902A Measuring Receiver but cannot find a 11715A. The lowest distortion source I have on my bench turns out to be an HP 8640B!

[@tgsoapbox]

Thanks for the comment - Those 11715As are not replaceable as far as I know which is why they still command around $1K+ on eBay. The service manual goes into details on how to test the output so you might be able to work something up yourself but I suspect that it might be a special application type thing.

[@davidv1289]

@@tgsoapbox Thanks for the reply. I thought that might be the case. There are currently none available on evilBay and the places that will give you a price want $1 -2 Kilobucks. I mostly need it for the AM and FM distortion checks. My back-up plan is to use an HP 8901A that I can run comparison checks against using a splitter from my source generator modulated by the 8903 and check for matching readings - not my preferred method but.......

[@lorenzosegundomoralesiriba1800]

phase alignment sum and dif cables