OTA V/U Antenna Combiner Recommendations?

[Kansas Zephyr]

I have a CM-4228 (UHF) antenna in my attic that has worked great.

I was hoping that there would be enough gain to still snag channels 8 and 12, after they went back to VHF, leaving their UHF temporary assignments. Well...no dice.

So, I'm adding a VHF antenna...no biggie. Right? I got a Holland UVSJ separator/joiner rated at 0.5dB MAX insertion loss.

Well...I noticed a 50% signal drop (...that ain't no 0.5dB!) on all UHF channels using it! So, I've removed it, with the signal levels returning to "normal".

Anybody have experience with a V/U antenna combiner with minimal loss?

[litzdog911]

"50% signal drop" based on what meter? The DirecTV signal meter does not show signal level or power. It's more of a quality index based on digital bit error rates. The closer the reading is to "100%", the fewer the bit errors.

If you're using the DirecTV signal meters, then it's quite possible that the combiner is introducing some signal issues (reflection, multipath, etc) that's increasing the bit error rate.

[jdspencer]

Isn't the 4228 supposed to be able to receive the high VHF channels?
My guess is that the high VHF are getting attenuated by your roof. Try it outside as a test.

[BattleZone]

Isn't the 4228 supposed to be able to receive the high VHF channels?
My guess is that the high VHF are getting attenuated by your roof. Try it outside as a test.

That was going to be my suggestion too. You're going to have problems trying to combine two VHF antennas catching the same signal. Far better to move your one antenna where it can receive the signals properly. More height and less obstruction is what you need. You may also need a pre-amp.

[raoul5788]

Isn't the 4228 supposed to be able to receive the high VHF channels?
My guess is that the high VHF are getting attenuated by your roof. Try it outside as a test.

My experience is it varies by the channel. Here in CT I get channel 10 well with my 4228. I have read it doesn't get channel 9 so well.

[Kansas Zephyr]

Nah...going to keep it in the attic. To much trouble to test, since I'm not willing to mount it outside.

Yes, there is some small gain on VHF-Hi with the CM 4228. But if you check this out you'll see there are nulls on channels 8 and 12...which are the ones I want.

http://www.hdtvprimer.com/ANTENNAS/cm4228.html

Remember that a V/U combiner isn't a reverse splitter. There are band-pass filters, with one input for UHF and the other for VHF. So adding the VHF antenna shouldn't be an issue. Plus, I should mention that the stations I'm missing are farther away, and at a slightly different heading than the stations I receive with no issues.

I have a CM-7777 preamp...but there's no electrical in the attic to power it...and it feeds a SWM-8 which is outside. So, I can't inject power there either.

The multi-path comment makes me think I may try some different cable lengths from the antennas to the combiner to see if there is any impact, too.

[Davenlr]

I was just going to suggest a 7777, as its what I use here, and it does an excellent job of combining V/U. In your situation, I would consider running a coax from the amp to your central location, and bypassing the diplexers, or running power to the attic or the SWM8 location. Most houses have a few access holes between the attic and under-house where you could drop a romex cable through, and tie in.

[Kansas Zephyr]

Most houses have a few access holes between the attic and under-house where you could drop a romex cable through, and tie in.
Yeah...It's not "most houses". I have a solid concrete pour "bathtub" basement. There is no crawl space...and an all-brick exterior. That's why the SWM-8 was a must have for me...all of the rooms were pre-wired with only single coax runs.

My only option to get power in the attic would be to add an outlet, by tying into a junction box that provides power to the garage door openers, since the attic space I'm using is above the garage.

I average >75% on all of the other channels, and am leery of overdriving, too.