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Do you have the schematic of the stage ? if so can you share it ? Let me render a few comments / thoughts on this : 1. The first thing that needs to be established is whether the original part is a

I'm not sure what "ham friendly" means, but HP has had many models over the years that will hit 18GHz. Some to look for are the 5340A (very old, but good), 5350, 5351, and the rest of that family. The

Hi Tony and George, Yes I did build up the power supply in my HP 8663A with 4 Mean Well modules. Looking back on posts I made at the time, here is some info from this post:

The best microwave counters in my view are EIP 545 or 548 series , they are nice counters and you can get them reasonable priced , EIP used a YIG filter on the microwave input which protects the

Hi if you are looking for a counter with GPIB then the questions have to be What functions do you want ? Highest frequency ? How much is in the bank for it ? counters can do more than just count for

I've encountered a fair number of Autohet(Racal-Dana) microwave counters at hamfests and e-fleas for under $100. They're rack mount affairs, so not as convenient a form factor as your counter.? The

Hi again, I am installing my HP 5342a counter, which is working, but it never came with GPIB i/f. I see the manual specifies option 001, with P/N?05342-60019 HP/IB Assy and P/N 05342-60029 HP/IP

Hi Bob, I am working on my own RYTHM with some success. Can you do the following: Insert CW at 4GHz, -20dBm. Apply the following settings on E4407B: Center freq 4GHz Span 250MHz Resolution BW 1MHz,

It could be that there is a software limit but the spec on option 05 was 46GHz so it should not be to hard to figure out Sent: Wednesday, May 25, 2022 1:07 PM To: HP Agilent Keysight

Another possibility is an LED. The large bandgap leads to exceptionally low leakage. Breakdown voltage shouldn’t be a problem (certainly better than a 3904’s b-e Zener voltage). Capacitance is

wrote: The unit I bought arrived at my friends, but the higher frequency input was non-functional. Luckily the seller had another, which functioned okay. But there seems to be a hard limit at 43 GHz.

Got it. That's confirmed here as well. Doing too many tasks at the same time here to do any of them properly. I shall sit in the corner for a few mins with the dunce hat on! By elimination of ideas,

Agreed. The anode of CR9 is held at approximately -3.92 V unless something takes current away from CR11 and the only thing that can do that is reverse current through CR9. Orin.

---- When the node is clamped to let's say +5V, CR9 has (+5V-(-3.92V))=8.92V reverse bias. In the sim you should see CR8 and CR9 seeing ~ 2*3.92V+0.7V reverse bias in the extremes of the over voltage

Chris Smith: Looking at the schematic there is indeed polarity clamps for + & - excursions using CR9 & CR 8 going to 3.9V zenerdiodes, CR11 & CR10, that reverse bias the actual clamping diodes CR 8 &

Agreed. That would be extremely useful. The -40V rail's operating spec max is 0.5A - so I can increase the current dummy load I have in place by quite a way yet - I'll try that next. thanks Tony

I did a simulation of the clamp and it clamps at 5v, both polarities which is under the 6v reverse breakdown so the thing shouldn't get zenered. It's a bit tight though! As for the JFET pricing, it's

FWIW, Mouser have over 8000 PN4117A. at $3.17 each. I don't know how easy/expensive to get them to ship in the UK though. You don't need the metal can version - HP switched to plastic packages for

Orin Eman: The B-E diode is zenered by back reversing it. It increases 100s times or more increases the B-E diode leakage if zenered once. There is a need for back to back 2N3904 B-E diodes to avoid

The 1901-0586 is also used in the 34702A, in which it is listed as "DIODE: SI 30 WV 10PA LEAKAGE", so I would say that a low-leakage JFET would be a perfect choice as a replacement. A 2N4117 or its