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Old 9-May-2019, 4:20 PM   #1
newmguy
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Join Date: Apr 2016
Posts: 37
combining an RF signal with my OTA antenna

Hello everyone,

My house is a 2 storey home where there is only an RG6 coax cable going to the top level of my home.

I use a netmedia triple play modulator (MM73)
http://www.netmedia.com/modulators/mm73.html
to combine composite signals from three devices to one coax cable outputting on UHF analog channels 60, 62 and 64.

I am trying to combine my OTA antenna with the output of the MM73 using a regular splitter/combiner.
I am using a good quality splitter, (I've tried a few, that isn't the problem).

The splitters I tested are Antronix CMC2002H OR BGI SGHMQK-2, both give the same results.

The OTA signal is great as this is just for a 2nd TV set for the guest room.
When I connect the MM73 output to the splitter/combiner, the upper UHF channels go to zero signal strength.

These channels are 43 (647 MHz) to 49 (683 MHz). There are two local channels in that range
that are usually 100% signal strength and 100% quality. They are channels 44 (653 MHz) and 47 (671 MHz).

If I leave the splitter connected and just disconnect the MM73 output from the splitter it works great.
As soon as the MM73 is connected, the channels mentioned above go to zero signal.

There are no amplified splitters, preamps or anything else in the line other than what you see in the picture.

The MM73 modulator can transmit on UHF or VHF and is configurable. I tried only using one output and transmitting
on channel 30 UHF but the result is the exact same.

I even tried a 7db attenuator on the MM73 line going into the combiner, same results unless the MM73 is disconnected.

I hope someone can give me some ideas on what to try. I really don't want to have to fish a coax cable up and crawl
around in the attic when there must be a simpler solution.

Any help is greatly appreciated.


Last edited by newmguy; 9-May-2019 at 8:37 PM.
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