Splitting/diplexing problem

[ddebehnk]

I'm wondering if anyone can help me.  I am trying to add another DirecTV/HDTV receiver to my system.  I currently have a Hughes E86 and get DirecTV HDTV programming and am using an OTA Channelmaster HDTV antenna in my attic in Hartland.  If I run my OTA feed directly to my current receiver I get the following signal strengths (and good picture):

08-100%
28-100%
34-100%
46 72%
25 72%
61-30%
35-100%
22-30%

I tried to run my OTA feed through my Multiswitch and use a diplexer at the receiver end (to test how I would add the other reciever to the system).  I am using a Trunkline Model 35TRDS8 5x8 multiswitch (40-2150mhz) and a 40-2150 mhz diplexer.  When I do so my satellite signals are fine but my OTA signals drop to the following (all others remain at 100%):

46-15%
61-0%
25-0%
22-0%

If I just try to place a 5-2150 mhz splitter on the OTA line I get the same drop in signal strength on those channels.

My plan was to add another Hughes E86 receiver to our great room (the other one is in the theater) but I really want to get the signal strength issue sorted out before I drop the money.

Any thoughts?





All

[foxeng]

My plan was to add another Hughes E86 receiver to our great room (the other one is in the theater) but I really want to get the signal strength issue sorted out before I drop the money.

Any thoughts?

You might consider a powered splitter. I bought a 4 way powered splitter from Radio Shack and it seems to work well with DTV. What it does is amplify the signal just enough to over come the loss of the splitting process.

[wxndave]

What are you using for an antenna?  

Dave

[ddebehnk]

A channelmaster HDTV antenna

[mhz40]

Originally posted by ddebehnk
If I just try to place a 5-2150 mhz splitter on the OTA line I get the same drop in signal strength on those channels.Any thoughts?

All

A two way splitter will only lose 3.5 dbmV.  Maybe your splitter is bad---or have a bad connection somewhere.  You sure it's 5-2.1GHz?  I don't recall ever seeing one of those, but then again I don't play with consumer satellite stuff...

MHz

[wxndave]

Looking at your signal strength.  The stations that you are having problems with are lower power.  They are running under 1000 watts output.  I consulted with another Television RF system Engineer and he recommends the Winegard DA-0405 preamp.  This passes the vhf signal and amplifies only the UHF signals from 470-890 Mhz.  You can get this amp mail order from Stark Electronic.  //www.starkelectronic.com.

Dave

[ddebehnk]

Thanks Dave

Do you know if I need to put the pre-amp right after the antenna but before the multiswitch or splitter or can I add it on the line before it goes to my receiver.  I'd rather add it to my wiring closet than climb into the attic to add it by the antenna!

Thanks again.

[mhz40]

Originally posted by ddebehnk
Thanks Dave

Do you know if I need to put the pre-amp right after the antenna but before the multiswitch or splitter or can I add it on the line before it goes to my receiver.  I'd rather add it to my wiring closet than climb into the attic to add it by the antenna!

Thanks again.

Generally amps are used to mitigate the signal loss of the cable, not the deficiency of the signal off the antenna.  Therefore if at all possible, the pre-amp should installed right at the antenna.
If you have any strong analog off-air channels (18, 24, 36, 58), amplifying your signal may cause more harm than good in terms of distortion products.  In addition, if the digital carriers are too low at the antenna, amplifying them will only give you a stronger "noisy' signal.
What you really need is a friend in the cable TV or antenna business and ask him to quantify your actual RF levels with a signal level meter.
IMO, signal strength as reported on the receiver is useless.  It's most likely 'signal quality' (Bit Error Rate), not strength.  Strength is measured by absolute level in dBmV... a meter will give you that.  From there it's just a little engineering, which would provide something better than a guess as to the results you may experience --- or proceed down your current path and simply 'shotgun' it, maybe you will get lucky... or maybe your overall reception will get worse.  In either case, good luck!

MHz