[mythtv-users] Using Two DTAs with One PVR-500

[Kirk Bocek]

The short answer:
Use a channel 4 signal combiner.

The long answer:

As part of Comcast's analog shutdown/ClearQAM Encryption process I'm getting a 
couple of their DTAs hooked into my MythTV setup. Comcast gave me Motorola 
DTA100s but this would apply to the seemingly more common Pace DC50X DTAs as 
well.

These DTAs offer *only* a single RF/Coaxial output with a channel 3/4 
selector. The problem is that my ancient PVR-500, while having two internal 
tuners, has only a *single* physical RF/Coaxial input.

If I try joining the DTAs using a passive cable splitter, channels 3 and 4
bleed over onto each other and cause interference.

The answer is to use a channel 4 signal combiner. This box is intended to 
allow the use of an OTA antenna along with an STB. It has two inputs and one 
output. One input 'notches' or removes channel 4 while allowing everything 
else to pass. The other input allows channel 4 to pass while filtering out 
everything else.

I ended up finding a JVI 40-SC4 for about $12 on Ebay. If you Google "ch-4 
signal combiner" you can find a few other manufacturers. I even found a 
channel 3 combiner which should work just as well. I saw some amplified units 
but that would be unnecessary since the RF signal is being generated by the DTAs.

Here's my final "DTA Pod":
http://imgur.com/zXmzW

The IR emitters are taped the DTAs with black electrical tape to keep them 
from interfering with each other. I haven't attached it yet to my PVR-500 but 
the two signals have been rock solid on the TV I've tested it on. I'm certain 
it will work once I get it attached to my PVR-500.

If there's a more elegant solution, please share.

Kirk Bocek