Counter HP 5342A sensitivity - Page 1
Forum section: electronics / testgear

author: frantisek
author_rank: Regular Contributor
timestamp: January 26, 2024, 09:24:23 am
content: Please advise!! I want to buy a counter HP 5342A. In all the manuals I downloaded the input sensitivity I500 MHz - 12.4 GHz -25dBm12,4 GHz - 18 GHz -20dBm.The seller claims that these are figures for an older generation and the sensitivity is-22dBm and -15dBm. I haven't found this data anywhere... Is the seller right? Please answer!

author: srb1954
author_rank: Super Contributor
timestamp: January 26, 2024, 12:12:15 pm
content: Quote from: frantisek on January 26, 2024, 09:24:23 amI think the seller is trying to mislead you. The sensitivity figures for the 5342A are as per your figures in both the 1982 and 1987 catalogs.Even if HP did come out with a later revision they would be very unlikely to have degraded the sensitivity specifications as that would have created issues for customers making repeat purchases of this instrument.

author: Orange
author_rank: Frequent Contributor
timestamp: January 26, 2024, 03:05:54 pm
content: The typical sensitivity of a good 5342a counter is about -25dBm at 18 GHz. I checked mine and it was -28dBm, so well within spec.A -15dBm counter is not good. Maybe the sampler head is damaged. if one of the diodes is blown in the sampler-head you see decreased sensitivity.Sampler heads are difficult to get, and if you find them they are expensive.Another possibility is the IF strip that has a faulty MMIC. The 5342A is notorious for this kind of problem. A good first check is the selftest of the 75MHz signal in the counter.

author: alan.bain
author_rank: Regular Contributor
timestamp: January 26, 2024, 05:32:56 pm
content: There is a sensitivity test procedure in the service manual and like many HP things of this generation every example I have seen passes it with some margin.On the lower frequency 50 ohm input I found my example had sensitivity hugely reduced which was caused by drift of the small wattage carbon composition resistors providing DC bias to one of the differntial amplifiers on A3 board.

author: frantisek
author_rank: Regular Contributor
timestamp: January 27, 2024, 05:11:22 pm
content: Thank you very much everyone!

author: frantisek
author_rank: Regular Contributor
timestamp: January 28, 2024, 10:27:11 am
content: Thanks again everyone! I'd like to ask one more question. The seller states: 15GHz -21dB, 16GHz -18dB, 17GHz-16dB , 18GHz -15dBSo is the input RF part distorted? Is it a serious fault? Can it get worse over time? What does the 75 MHz test verify? Thank you in advance for the answer.

author: Orange
author_rank: Frequent Contributor
timestamp: January 28, 2024, 12:25:10 pm
content: Quote from: frantisek on January 28, 2024, 10:27:11 amDoes it have option 002 or 003 ? With these options sensitivity drops also 5 dB. (Dynamic range extension and Amplitude measurement)These options are rarely seen on the 5342A, just be aware of this if you buy one.

author: frantisek
author_rank: Regular Contributor
timestamp: January 28, 2024, 09:54:15 pm
content: No the one with the values above has only: Option H16:Line variation: <r1 x 10-10 for 10% line variation(time base)I wanted to buy with option 001 and 002, but it wasn't on Ebay so they couldn't broker the trade for me. But in the photo the display didn't even light up... I guess that would be a pretty big risk. A decent one from the EU or somehow reasonable (VAT and CLO) I would buy. If they are, they are horribly overpriced.