Daniel Danny Horvat
danny.e73m at myantennas.com
Fri Nov 20 21:31:28 EST 2015
On 11/18/2015 6:05 PM, Dan Maguire via TowerTalk wrote:
I was particularly impressed with the "look inside" view of his 4:1 balun
along with the VNWA insertion loss and SWR measurement results as shown on
his OCF-8010E-3K page:
I'm not so impressed. The web site says that the
the test is done by the "back to back" balun method.
This isn't a very thorough test because one of
the cores in each balun isn't really doing anything.
A pair of back to back un-un's would similarly pass
this test. The test doesn't really establish that
the "balun" is a balun, only that it is an all pass
network when connected to another instance of itself.
A better design is to cascade a 50 ohm common mode choke
with a balanced 50 ohm to balanced 200 ohm transformer.
Well, Rick, I am not impressed too.
First, you are related to Agilent and did'nt recognized the S21 back to back
of two 4:1 BALUN's insertion loss measurement.
NOT the 1:1 Balun measurement!
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.
Second, your proposal of better 4:1 BALUN for OCF antenna involving 4:1
balanced transformer in cascade with current 1:1 BALUN is impractical, given
the fact that broadband 3-30MHz balanced transformer will always have more
insertion loss than simple 4:1 transmission line transformer formed with two
separate 1:1 current BALUNS.
After all, I don't care if I impress anyone with my work, all I care is to
put out all information about my products which is not usually the case with
many HAM radio products manufacturers.
I am open to suggestions and criticism.
Sorry if this response is not towertalk related.
73 Danny E73M
Owner of MyAntennas.com
Danny Horvat, E73M
Antennas & Accessories
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