Well, at HF they can be interesting.
You can easily build them in a trifilar transformer configuration...use a
large ferrite toroid or two and wind it around with three wires. I can
look up the exact wiring, I think it's pretty similar to a CT transformer.
I've built one to use as a "splitter" for a pair of phased
verticals...works fine. Two 2-1/2" diameter toroids will handle 1kW easily.
The trick on these things is the impedance of the ports. This one I'm
describing is R-2R...in other words, if two ports are 50 ohms, the other
two are 100 ohms. Of course, one pair of ports is in-phase and the other
antiphase.
If you want contact me directly and I'll dig out the text I built it
from...it's one of my old college books.
BTW, what is your reason? It almost sounds like a "balanced amplifier" in
the microwave sense.
At 02:32 07.10.1998 GMT, Doug Hall wrote:
>
>Some more amp-related questions:
>
>Where can I find good references on designing hybrid combiners? I'm
>looking for something that would allow two 500-700w HF amplifiers (fed
>by one exciter through a splitter) to feed one antenna. All ports 50
>ohms.
>
>Are such devices commercially available? Where can I buy them? Based
>on the little bit I've read about them it doesn't seem like it would
>be hard to build one. How broad can you make them?
>
>(Yes, I actually have a very good reason for wanting to do this, but
>I'm not interested in opening more than one can of worms at a time.)
>
>Thanks for any tips.
>73,
>Doug, KF4KL
>
>
>
>
>--
>FAQ on WWW: http://www.contesting.com/ampfaq.html
>Submissions: amps@contesting.com
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>Problems: owner-amps@contesting.com
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>
>
>
------------
Scott Townley
nx7u@primenet.com
------------
Collector of:
Stoddard Aircraft EMI/RFI receivers and accessories
Big Parts for that Big Linear Amp
70's era RF test equipment HP/GR/Tek
Radio-related technical reference material 1940+
...anything else that will keep me off the streets at night
--
FAQ on WWW: http://www.contesting.com/ampfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
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