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List your test equipment "scores" here!
alm:
--- Quote from: rastro on December 08, 2018, 04:26:43 pm ---I've had close to a dozen HP 8484A sensors from eBay over the last 5 years pass over my workbench and have had pretty good luck. I can't remember receiving any from eBay's "used" category being bad. I've also bought a few listed under "parts/repair" as unknown that also checked out OK.
--- End quote ---
The 8484A is a diode sensor. The thermocouple sensors like 8481A and 8482A may very well be different. Despite their higher maximum power levels, they appear to die more frequently. Probably because they are more sensitive to overloads. And there appears to be almost no chance of repairing them given the lack of spare parts and special skills available if the thermocouple is blown.
rastro:
--- Quote from: alm on December 08, 2018, 10:30:38 pm ---
--- Quote from: rastro on December 08, 2018, 04:26:43 pm ---I've had close to a dozen HP 8484A sensors from eBay over the last 5 years pass over my workbench and have had pretty good luck. I can't remember receiving any from eBay's "used" category being bad. I've also bought a few listed under "parts/repair" as unknown that also checked out OK.
--- End quote ---
The 8484A is a diode sensor. The thermocouple sensors like 8481A and 8482A may very well be different. Despite their higher maximum power levels, they appear to die more frequently. Probably because they are more sensitive to overloads. And there appears to be almost no chance of repairing them given the lack of spare parts and special skills available if the thermocouple is blown.
--- End quote ---
That's a good point. I think the thermocouple is also more sensitive to shock.
I would agree that the 8484A are pretty sturdy. Even though they have a max of -20dBm; I believe they can tolerate +30dBm for short periods. I probably wouldn't deliberately chance it.
You bring up a good point regarding the themocouple sensor being a bigger risk. I can't speak for the 8481/2A's however I have had at least three 8481D's from eBay without any trouble - the "D" version might be diode sensors also.
rastro
Neomys Sapiens:
--- Quote from: rastro on December 08, 2018, 04:26:43 pm ---After fixing the cracked plastic clip that holds the sensor cartage wires to the PCB it zeroed and calibrated fine. Yes you would need to have it re-characterized if you move or mess with the sensor cartage.
You may also lean toward the 437 since you can store the calibration coefficients in a frequency lookup table - some added convenience.
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What is the assumed meaning of 'cartage'?
orin:
--- Quote from: alm on December 08, 2018, 10:30:38 pm ---
--- Quote from: rastro on December 08, 2018, 04:26:43 pm ---I've had close to a dozen HP 8484A sensors from eBay over the last 5 years pass over my workbench and have had pretty good luck. I can't remember receiving any from eBay's "used" category being bad. I've also bought a few listed under "parts/repair" as unknown that also checked out OK.
--- End quote ---
The 8484A is a diode sensor. The thermocouple sensors like 8481A and 8482A may very well be different. Despite their higher maximum power levels, they appear to die more frequently. Probably because they are more sensitive to overloads. And there appears to be almost no chance of repairing them given the lack of spare parts and special skills available if the thermocouple is blown.
--- End quote ---
There is a company on ebay that will fix 8481As or sell you a fixed one for around $450.
Expect any 'untested' 8481A or 8482A to be broken. Even those that zero may be compromised. I've returned two 8481As - the first because it failed on SWR though it would zero and measure power, the second because although it would zero, it didn't actually measure power. I did however manage to get a working 8482A. I have an 8484A as well, but it tends to drift.
cncjerry:
I thought the 'D' power sensor models were the diode type? for instance 8481d, 8482d, etc.
Thanks for all the input. This is all complicated but I'm starting to understand what I need.
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