[TowerTalk] ...and another coax adapter question

[Scott Townley]

I stand corrected; yes I neglected mismatch loss.

Re-calculating using datasheet max values gives Pdiss values that 
decrease with increasing frequency, which is what I would have expected 
(but didn't get the first time).  I realize datasheet values are just 
that, all I'm trying to do is to get a feel for what the relay can do.

I can see from the discussion that measurements can't predict 
everything.  Fortunately for me I don't use 'elbows' or RA-coax 
connectors at all (too many bad experiences at work, even with 
'professional' grade stuff).

Thanks all for playing!

On 25/11/2023 20:24, Richard (Rick) Karlquist wrote:
> You misunderstand what the definition of "insertion loss" (IL) is, as
> used by RF component vendors.  IL = incident power (input) - 
> transferred power (output).  The device under test (DUT) has both 
> "mismatch loss",
> where some of the incident power is reflected back to the source and
> therefore is not transferred to the output; and dissipative loss,
> where power is lost by being absorbed by heating the DUT.  So called
> mismatch loss does not result in heating of the DUT.  Your
> calculations are not valid.  Hope this makes sense.
>
> 73
> Rick N6RK
>
> On 11/25/2023 10:51 AM, Scott Townley wrote:
>> If that's the case, then wouldn't an insertion loss test reveal such 
>> an issue?
>>
>> For example, I was deconstructing the power handling of a Charter 
>> Engineering B5-series coaxial relay (N-female connectors).  If I map 
>> "max insertion loss at x GHz" to the average power rating on their 
>> published chart, at every point the dissipated power comes out to 11 
>> watts.  That tells me that "good" N-connectors can dissipate 5 watts, 
>> and for that mechanical form factor I should be able to derive a 
>> power limit based on measured insertion loss.
>>
>> Or are the physics of power handling in "not-so-good" connectors 
>> different from what would be revealed by an insertion loss 
>> measurement? Assuming of course that we are not in the realm of high 
>> voltage breakdown of the dielectric (or maybe that's exactly the 
>> difference?).
>>

-- 
Scott NX7U