Batboard

We have a digital astro UHF system using 4 channels connected to a TX/RX Combiner. We use one antenna for TX and the other for RX. Our Quantar is set for 110Watt output but after the combiner we are only getting 35Watts output.. Is this much loss standard for such a combiner..??

Dover IT wrote:We have a digital astro UHF system using 4 channels connected to a TX/RX Combiner. We use one antenna for TX and the other for RX. Our Quantar is set for 110Watt output but after the combiner we are only getting 35Watts output.. Is this much loss standard for such a combiner..??

I think every combiner is probably made to certain specficiations. You'd have to give us a lot more detail about your particular combiner for us to help you.

-Alex

A 4 port Hybrid-Ferrite combiner usually has about 7 db loss and the Cavity-Ferrite types are in the range of 3-5 db, depending somewhat on the channel frequency separation involved. As Alex said it depends on the particular equipment involved but I would generally expect to see somewhere in the range 20 - 50 W out for 110W in for a typical 4 transmitter installation like yours. Your 35 W is probably normal depending on the spec for your combiner.

My two bits worth:
We need to know exactly what kind of combiner you are using to answer your question. It certainly sounds like a 4 port Ferrite-Hibred.
(does NOT have big , shiney cans)
You could call TX-RX with your model, and serial number, which is on the unit, they can tell you exactly how much loss to expect.

You are reporting an insertion loss on one channel of about 4.6 dB. Depending on the design of the system, this could be normal, though it is higher than I've seen in recent TX/RX designs. As others have noted, we would have to know more about the system design to say that this loss is either normal or excessive.

One quick thing to look at: are all of the ports on the system in use, and, if any are currently vacant, are they properly terminated?

One other thought: TX/RX usually supplies a system design before the hardware is assembled; one page of that design is a line diagram showing each transmitter, receiver, and can. Annotated on the path lines are expected insertion losses. You should locate and examine that system diagram to see if the insertion loss you are observing was predicted.