Help me find old microwave equipment gems - Page 1
Forum section: electronics / rf-microwave

author: maxwell3e10
author_rank: Frequent Contributor
timestamp: November 14, 2020, 05:00:00 am
content: I am setting up a new microwave lab (in 10-20 GHz range) and of course would like to save money on equipment. But I don't have much experience with microwave equipment, so don't know good used microwave equipment models. I need generators, power meters, splitters, modulators, variable attenuators, etc. I am looking for suggestions of good models I should look up and try to find on used market. The lab will mostly deal with amplitude modulation, so I don't need broad frequency sweep capabilities but interested in fast and high dynamic range amplitude switching.

author: 0culus
author_rank: Super Contributor
timestamp: November 14, 2020, 05:14:07 am
content: How much power are we talking here? If we're staying below 1 watt, I'd say look for deals on HP gear. HP was to RF gear like Tektronix was to oscilloscopes in the good old days. If you're doing higher power, you'll want to look into having some suitable directional couplers, attenuators, and dummy loads to protect your test equipment.Since you're doing narrowband carrier work, you'll want an HP 8566B spectrum analyzer for sure. Great bit of kit, love mine. It's gottonsof capabilities if you delve into programming it. Controlling it from Matlab via the instrument control toolbox works perfectly in my experience. I have an 8672A signal generator; added bonus is the synthesizer architecture is practically identical to the 8566B, so repairs could be easier if you learn one. There was a related model that outputs up to 26.5 GHz but those seem to be quite expensive if it isn't a wreck. Might look into doublers if the disadvantages of that don't impact your use case.As for power meters, I am partial to the 438A myself. But all those series of power meters (436, 437, 438) use the same sensors so any of them will do. The meters are dirt cheap, but will almost never come with a sensor or a sensor cable. You'll probably have to plunk down a bit to get one that isn't blown up. If you look about ebay you can find a few sellers that repair them and guarantee them to work. You might eventually want to find a 432A meter and a working thermistor mount. These "closed loop" meters can be used as a primary standard to sanity check your open loop power meters. Keysight will still service the thermistor mounts, for a hefty sum!

author: maxwell3e10
author_rank: Frequent Contributor
timestamp: November 14, 2020, 05:33:05 am
content: Thanks for the suggestions. Yes, HP would be an obvious choice or maybe slightly newer Agilent, so I need to wade through a long list of models. This is not a hobby lab, so I am not necessarily looking for absolute cheapest equipment, a few k$ is still a bargain compared with new stuff.I don't need high power, actually more very low level signals. For power meters I need a fast rectifier type to get rapid response with analog output.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: November 28, 2020, 09:55:49 pm
content: Join this group and see if anything pops up. There is a real fancy 40 GHz VNA for sale under 5KLots of other stuff comes up.https://groups.io/g/test-equip-traderAlsohttps://groups.io/g/Test-Equipment-For-Sale-Wanted-or-Exchange

author: maxwell3e10
author_rank: Frequent Contributor
timestamp: November 29, 2020, 02:16:05 am
content: Thanks. First I need to decide what I want