[TowerTalk] Myantennas

[Jim Lux]

On 11/21/15 4:04 AM, Richard (Rick) Karlquist wrote:
>
>
> On 11/20/2015 6:31 PM, Daniel Danny Horvat wrote:
>
>>
>> BTW I own an old HP/Agilent 8711 network analyzer and would love to
>> here how
>> would you measure insertion loss of 4:1 (200:50) TLT with any network
>> analyzer? Enlight me please.
>
> Not with just "any network analyzer", like the 8711; you need a 4 port
> network analyzer, such at the Agilent E5071C with 4 port option.
> I've measured many baluns with one of those.  Gives common mode
> and differential mode s parameters, with programmable Zo for
> each port.  Also measures imbalance.  The Agilent software will walk you
> through the set up.
>
>>


Isn't there a process (perhaps tedious and manual) to do this with a 2 
port analyzer?  Where you connect each pair of two ports in turn (so 
there's 6 of them AB, AC, AD, BC,BD, CD) and then in each configuration 
connect a short, open, load (or any 2 or 3 known Z) to the other ports. 
  Then you can solve algebraically for the full 4 port matrix.

Given the number of inexpensive two port analyzers out there these days, 
it might be worth figuring out how to do this kind of measurement

Just out of curiosity, how do you connect the 4 ports to a Balun, which 
is sort of a 3 terminal device?  Where do the "ground/shield" 
connections go?

(I just got a file of S-parameters for a minicircuits transformer, with 
all 16 S parameters, so I suppose it's similar..)