estimating RF filter power handling capability by size? general ID by temp?

[CopperCone]

Lots of shit on ebay with no real specifications to be found. old, appears only in catalogs.. new versions cost order of magnitude more.

Is there some way to estimate if something is like 1 watt, 10 watt, etc?

Is it a safe bet to say if somethings got N connectors on it, its good for 10 watts?


Same with isolators: Can you find one of particular size and assume others of similar size have same power handling capability?

how about filter pole count estimation?

what a fucking mess


can you measure temp of these things to determine usability... like run for a minute and see if its physically hot? or is it gonna be internal problems that don't couple well (i don't know whats in these cans).

Interested in stuff <1GHZ

[T3sl4co1l]

Congratulations, you've discovered why they cost orders of magnitude less.

You could do lots of things, time permitting.  Buy a couple, blast power at them, see where the one fails, then use the other at some reasonable derating from the failure point.  (Or see if the frequency response changes when too hot, or changes permanently, even.)

You could desolder / drill / cut / dismantle one and see how hot it gets internally, or inspect its components to get an idea of ratings.  In some of these cases, you could still put it back together.  Some not.

Plenty of money to save, if your labor is heavily discounted.

Tim

[CopperCone]

how about stuff that uses cavities/bolts for tuning? Can you just measure those?

[CopperCone]

how the hell do you run an isolator w/o a chassis, i thought its a piece of waveguide with magnet

[Neomys Sapiens]

You can make valid assumptions only within a certain technology, that is compare LC filters to LC filters and cavity filters to cavity filters. Within a technology, body size can give you a better idea of power handling capability than the connectors, as those are mostly chosen for seamless integration into the user's system. The big unknown factor is the number of stages/poles, as those need space as well. Maybe taking the filter's curves, then looking at comparable products will give you a better clue.
As for circulators, your notion is correct. It was probably not meant to run them while disassembled.

[CopperCone]

I just bought a bunch of high power isolators on ebay.

Assuming I series these up, the reflection from the fried filter should protect my power amplifier right (I got 4x 25w circulators with 20db of attenuation each).

The power amplifiers are 10 watts;