HP 436A+8484A - Page 1
Forum section: electronics / beginners

author: hnjmkl
author_rank: Regular Contributor
timestamp: May 01, 2022, 05:49:07 am
content: I have a chance for an HP 436A + 8484A for $ 295, is it worth buying as a hobby or is it better to focus on other things?

author: Stray Electron
author_rank: Super Contributor
timestamp: May 01, 2022, 01:45:59 pm
content: Read the other threads on this same topic. the chances of getting a GOOD used sensor is about NIL. That said, I have a HP 438 with a couple of working sensors and I've never used it. IMO if you have to ask if you need it, then you don't.IF you are still considering buying it, I would strongly suggest only buying it after you've tested and making sure that the sensor and cable are good. Meters by themselves are CHEAP. 90% of the value is in a WORKING sensor and about 8% of the value is in the sensor cable.

author: MarkL
author_rank: Unknown
timestamp: May 01, 2022, 01:46:23 pm
content: I think only you can decide if it's worth it for a hobby.The only thing I would caution against is to make sure it's guaranteed working (if it's on ebay, condition: "Used"). A large majority of RF power sensors on the used market are damaged from too much power input, and they are not repairable. Also, make sure the calibration table on the side of the power sensor is intact. I have seem some where it has been removed or defaced. You need this data to make accurate power measurements, or get the sensor re-calibrated to generate a new table.

author: rfclown
author_rank: Frequent Contributor
timestamp: May 02, 2022, 12:40:46 am
content: You also need a 11708A reference attenuator and a cable. I wouldn't pay $295 for only meter and sensor. Sensor by itself might be worth $200, and 436A $40. I consider $50 a reasonable price for a cable. The only way I've been able to unload the units that I've had is to offer everything together: 436A+8484A+11708A+cable and show in the ad that it all works... otherwise I can't get any money for the most expensive item (the sensor). The 436A by itself, you can't get enough money (on eBay) to make it worth the trouble selling (IMHO). They work, but you can't get any money for them. I got mine in the first place because they were SO cheap on eBay.

author: Tony_G
author_rank: Super Contributor
timestamp: May 02, 2022, 04:03:29 pm
content: Stray Electron & RFClown are absolutely correct here - If you can't verify the sensor working before you buy, have all of the bits provided and the seller has a true refund policy/guarantee then I'd skip it.MarkL makes a really good point on the calibration factors - I too have seen some that lack the list and you absolutely need that to use the sensor (you just can't use a "default" list or a list from another sensor and expect the results to be accurate).Now that said, I have managed to snag a couple of inexpensive sensors by asking the seller to provide photos showing the sensor zeroing, calibrating, and reading something. However, you also have to be in the position that you can accept either the complete loss of your money or the arbitrary & capricious outcome of the eBay dispute resolution process.Final comment, I've actually had good luck with the 8484A sensors as they are diode-based and are a little more tolerant of power excursions than the thermocouple-based ones (YMMV, these are still sensitive devices and are easy to blow if you aren't careful).TonyG

author: hnjmkl
author_rank: Regular Contributor
timestamp: May 03, 2022, 05:20:01 am
content: The seller is an OM, in the announcement he offers to try it in his laboratory, despite this, given my zero competence on this type of instrument I give up. I will focus on some projects using AD8307-8318-8317, I have a DIY microwatmeter with AD8307 loaned by a friend to test, I must say that despite the low cost and the 500 MHz limit, it behaves quite well in readings, for a beginner like me maybe it would be the best choice, and also the fun in making it.