• Get involved.
    We want your input!
    Apply for Membership and join the conversations about everything related to broadcasting.

    After we receive your registration, a moderator will review it. After your registration is approved, you will be permitted to post.
    If you use a disposable or false email address, your registration will be rejected.

    After your membership is approved, please take a minute to tell us a little bit about yourself.
    https://www.radiodiscussions.com/forums/introduce-yourself.1088/

    Thanks in advance and have fun!
    RadioDiscussions Administrators

Combiner

Are these 1 kW transmitters all phase coherent for r-f and modulation, and if so, what carrier frequency?
//
 
Sorry. I didn't explain. They are 1kw RF Amps, 50 ohms, N connector outs, FM 88-108. I need a combiner for them to combine their individual 1kw to 4 kw.
 
All four 1 kW amps will need to be driven by the same r-f source, with the same r-f phase. Normally that is done by splitting the output power of a single FM exciter, by one of various methods. So the exciter must be rated to supply the total output power needed at the inputs of all four 1 kW amplifiers, plus splitter and cable loss.

Then probably the cleanest way to combine the amplifiers while supplying the isolation needed between their output circuits is with three 3 dB hybrids and associated reject (dump) loads. There are other issues in doing this such as providing common control, r-f monitoring and protection circuits for the system.

This system design and test, and the FCC documentation needed to use it legally on the air will not be a trivial exercise.
//
 
Miracle -
R Fry isn't kidding... I assume you are looking for 5KW of FM, since in another post you're looking for a 5KW transmitter. It will likely be less expensive to locate and purchase a 5KW transmitter used than it will be to get four 1KW RF amps to play together properly and without fighting. And, depending what you find used, you may well end up with a modular radio which in fact has such a combiner in it. Take a close look at it, all that junk is in there for a reason... the manufacturer in a very competitive market put as little stuff as he could get away with in the box.
Rather than reinvent the wheel,why not pick from one of the many available wheels out there?
 
These are 2 different issues/subjects which is why there were not posted together. The fact of the matter is that I have a client who has [4] 1kw rf amps in an old Transmitter. I am not sure of the model. His combiner fried and is not replaceable. He is trying to salvage it by finding a replacement combiner. That is all.

I am still looking for a 5kw transmitter for myself. Separate issue.
 
Comes the dawn :)
If the original manufacturer can't help you, you're likely hosed. Any idea what make the box was which ate the combiner?
 
Status
This thread has been closed due to inactivity. You can create a new thread to discuss this topic.
Back
Top Bottom