Originally Posted by nobleach
lol! yes.... and sadly, I've lost DBs of my own
So no signal loss?
Tell me about it, I have lost some that took weeks to rebuild. Since them I double backup my data to two NAS boxes.
All combiners have loss, and without good test equipment it becomes hard to say how much. Pretty much at the mercy of the manufacturer.
The guy that made the post AntAltMike here:https://www.avsforum.com/avs-vb/showt...php?p=15211452
On Monday, I just coupled a few UHF antenna into VHF downleads on a large building with about a dozen antennas, using whatever Pico, Holland, Centronics and unlabeled "UVSJs" I had on hand. I measued in-band insertion losses ranging from .2 dB to about one and a half dB. The losses through each band joiner varied over the UHF spectrum, but not with or inverse to frequency. They just fluctuated over the spectrum.
I know of no reason to believe that any UVSJ has any more or any less insertion loss than any other, and I'm sure I have installed more of them than anyone here. And you couldn't even measure loss precise to tenths of a dB using an antenna as a signal source just by rapidly switching componenets, because the output level coming off the antenna will continuously fluctuate by a few tents of a dB, even with a clear line-of-site to the towers,
I totally buy into what he is saying. Though I don't have the experience with comparing them as he does, nor the equipment, his argument is sound from my RF (Radio) background.
Basically he says they all seem to work about the same (they are very simple inside and very little way to make one different). Also the part where he says they are non-linear over the UHF spectrum, unrelated to a rising or dropping frequency, and they are not all the same. Normally (in case you don't know), the higher you go in frequency on the same transmission device, like coax, connectors, one almost always sees a bigger loss at the higher frequency. So him saying he saw it fluctuate makes sense. This is because the path through the combiner is so short it doesn't change much with frequency. If it's just a wire balun type combiner, that means there are less frequency dependent part. But what does happen is UHF is short enough of a wavelength, that the 1/4 is only about 5 inches. Hence there can be resonance between the balun, the shields, or just the torrid itself inside that it responds different to different frequencies.
Bottom line, is even if one of the channels falls on a worst case according to AntAltMike, you should not see a problem. That is about the same loss at 20 to 25 feet of line. It is possible if you are right right on the edge, you will see a change for the worse. But normally in the real world 1.5db does not make or break a connection. You could tell if one of your UHFs pixelates from time to time, then it's possible you will see more with the combiner. If you don't see any now, you probably won't with the combiner.
The ultimate thing would be have test gear and a sack of combiners, then go through them and find ones that have the lowest loss on the channels you need. Of course this is only available to a professional installer with a selection in his truck and the test equipment.
In the end he is saying electrically, the UVSJ preforms as well as the expensive ones. What I leaned toward in my previous post was I like the construction of the Winegar and the Antennas Direct better for mounting outside on a mast. But that changes the price from $4 to $16, plus shipping.
To be redundant (works good for computers) this is why if you can find one antenna that does it all, you are ahead, not using a combiner.
But in your case you implied to me your UHF was working fine on all our UHF channels, which I guess I presumed solid no pixelization or drop outs. Add that to the fact you said you locked WNBW ch9 on a UHF yagi, means you don't need much VHF gain. Part of why I said a home made dipole or yagi outside combined with your present UHF would probably work fine or if lazy buy the little Antenna Craft 5 element high band beam.
Then I if I get more aside and verbose. I believe if I remember you have a little Radio Shack or equivalent UHF beam. That is about 10db of gain looking straight at a station, and tapers to 7 db about 25 degrees off either side, and normally drops off fast after that (out of the main front horizontal lobe).
Then considering the single combined antennas I have found (seems I keep missing some and some are new), there is a jump in beamwidth between the HD-1080, and the HD7694P. Though the HD7694P is not any narrower than your current UHF and not real tight on ch9 either. Which is best? Probably only a field test would tell. The 1080 is half the price of the 7694P.
Still the fact the Radio Shack works over the spread you have between WOGX and WGFL, means if you are splitting the difference, your beam then is only about 6db for those stations. Add to the you locked WNBW, to means the HD1080 would have plenty of gain.
I think you are close enough to all towers (maybe not WOGX) that any metal up in the air is line of sight and gets a signal. It is very possible if you put a UHF loop or single bow tie and a VHF dipole up 15 feet (clears the peak of your roof ) you would lock all the stations. If your brother in law lives near you and locks all the UHF on his homemade antenna inside, that means there is a lot of signal.
I Hope I didn't type to much. But I figure if you are a Unix/Linux sysop you have the type of mind like me were there is never enough information.
On another note, WNBW is looking bad for me. Skip was dead on VHF so I turned the back of my YA1713 at WFTV and nulled it into static and luckily that also meant I was pointing directly at WNBW.
But,, arggggggggggggg.. My TV's both looked on UHF skip from WFTV's ch39.1 signal mapped to 9.1
Dang this mapping! I doubles the chance you will have co-channel problems.
It is looking more and more like I need to proceed with stacked yagi's pointed down south to WESH.