I recently acquired an HP P532A frequency meter. I know it's a resonant cavity device that goes from 12.6 GHz to 18 GHz but I don't how or what to hookup to the two flanges to get it to work.

I've seen the Signal Path video but the unit he demos is a different frequency range and has connectors rather than flanges. There are some manuals and app notes on eBay but each is twice what I paid for the device.
I have signal sources and detectors in the correct frequency range, I just need to know how to connect to the flanges. Does anyone have any info they can share?

I'm going to post this on the HP forum as well but with a device as old as this one I thought I'd try covering all the bases.

Thanks,

John

Sounds like it expects to be connected to waveguides. What does your signal source provide as an output connection? At the time these frequency meters were designed, anything in that frequency range had a waveguide flange as the output connection.

I have several HP RF generators that go that high. Each has a type N connector.

Times have changed. Back in the day, waveguide was presumed to be the transmission line of choice for the really short wave lengths. As time progressed, it seemed that coax was okay after all, or at least coaxial connectors.

I recall struggling to understand TEM and such, the different transmission modes. As it turned out, I have a signal generator that goes to 2 GHz with an N connector, as well as a spectrum analyzer that goes to around 3 GHz, also with an N connector.

I don't know what they do these days up at ten or more times those frequencies.

Greetings to John and the Forum:

If I recall correctly, those devices were "suck-out" cavities. You connect an unknown microwave source to one flange and a waveguide adapter for a microwave power meter or diode detector to the other flange using suitable attenuators as necessary to get the power levels within what the wave meter and the detector can handle. Tune the 532A for a dip in transmitted power as read on the detector and read the scale on the 532A to get the frequency.

Regards,

Just a high frequency grid dip meter.

I don't think I would agree with that; a grid dip meter is an active device. These are passive. Of course, you can use a grid dipper as a wave meter, but how often does one use that feature?

Regards,

The only difference is that the grid dip meter includes its own generator.

These meters are really a variation on the absorption wavemeter theme. They consist of an adjustable resonant cavity that has been calibrated in frequency, designed to be placed in a waveguide between a source and a load. When the meter is tuned to the incoming frequency the cavity resonates, absorbing some of the RF power and producing a dip in the power measured at the load. It will work over a wide range of power levels, but they recommend that the power not exceed 70% of what the waveguide will handle. The P532A is meant to be used on WR-62 waveguide with UR-419/U flanges but you can find waveguide to coax transitions if you prefer.

When used as designed, the signal source you want to measure is connected to one of the flanges and a detector/load is connected to the other flange. This may be a crystal diode if an RF voltmeter is to be used, or a power sensor if a microwave SWR or microwatt meter is to be used. The diode or power sensor also furnishes the termination or load. So by themselves these meters don't really indicate anything, you have to provide additional equipment to make them useful.

Update:

I was able to find a pair coax to flange adapters. I thought I might just try making a set until I saw a pic of the complex interior.
I've attached a pic so you can see what they look like.

I'm primarily an audio and vintage radio guy so these frequencies are orders of magnitude higher than I'm used to. This will be an interesting change from 6550's and CX-201's!

BTW, a google search found the following manual for your meter: https://xdevs.com/doc/HP_Agilent_Keysight/HP%20X532B%20Ops%20and%20Service%20Manual.pdf

Thank-you Sir!

I usually use Dogpile for document searches, I'm surprised it missed that link as Google is one of the engines it draws info from.

Yea but is the receptacle on that waveguide adapter for a coax connector that is common? Like N? I have an HP cavity wavemeter from 3.7 to 12.4 GHz and it has N connections on it. So I screw a detector on one side and I have a small horn to N plug adapter for the other side that is out of a radar test set or something. I have only used it to check tuning of X band Gunn diode cavities. I can tune them either to the standard police 10.525 or the ham band below that. But not super accurately of course, as the scale is more compressed at that end of the range. I bought a cheap Chinese prescaler/divider for my counter that is supposed to work to 4.5 GHz. Seems to work but when there is no signal present, it still puts out random noise or something that registers on the counter. Or if you are outside of the window of it's input range it will start to read the frequency with greater errors. Maybe that is why they call it a X1000 divider instead of just a proper prescaler. 40$. Anyway, those are tunable cavities. You put a microwave sig in and the detector puts out a DC voltage. You tune till you see a dip in the output voltage from the detector, negative or positive depending on the orientation of the detector diode.
Tune for the minimum absolute voltage dip to read the frequency. OR just WATCH THIS VIDEO: https://www.youtube.com/watch?v=yWVkphJkV0k