Thread: Head Scratcher, 64772

I just got back from a hunting trip at Grandma's house; Dad got a nice, 180-lb white tail, and I got heartburn.

Her zip code is 64772 (Nevada, MO), and she's pretty far out there. Her main goals are KOAM-7 (ch7, 48mi), KFJX-14 (ch13(!), 48mi), and KODE-12 (ch 43, 55mi). It's really unfortunate that two of the three channels are VHF, but she has a decent combo antenna (10' boom, forward-swept VHF section, big UHF reflector), which used to do the job just fine using analog signals. Up until recently, a little Craig DTV converter box would also sometimes work to pull in channels.

I went down there this weekend armed with my cable prep tool, compression fittings and a Channel Master 7777 combo preamp, hoping that I could get her some more signal. According to my cable toner, the circuit from the TV end of the cable to the antenna is complete. Plugging in the 7777 didn't help, though; both her new Panasonic TC-P50X1 and my Dish DTVPal came up with zeros doing automatic scans.



My first mistake was that I didn't bring the TVFool report with me, not even the broadcast channel numbers. I didn't know that I was looking for ch 7, 13, and 43, so I couldn't tune to them and see if they blipped.

My second mistake was assuming that the balun was good. Because I got continuity, and I didn't bring another balun with me, and I didn't feel like dropping a 20' 1-5/8" fence pole to replace the balun, I still don't know if it got fried in a recent electrical storm.

Did I make any other mistakes, or is that balun probably the answer?

PS - Who the hell would take a perfectly good UHF station (14) and move it into VHF-Hi (13) for the transition?!?! It's like these broadcast engineers were trying to cut off viewers.

VHF is actually better for propogation--channel 2 is the best. This is because for the same directionality, the antenna is bigger and intercepts more signal. What makes you think that VHF is worse?

In RF theory, yes, VHF should be better (and was better for decades with analog transmissions). However, VHF and 8VSB is a provenly bad combination. Why do you think so many VHF channels are reapplying for UHF frequencies months after the digital transition? VHF vs UHF signal propagation shakes out to be about the same in the real world, if not actually favoring UHF in clear, flat terrain.

I don't quite understand the problem people are having with VHF signals except perhaps with an indoor antenna in a urban setting. I'm in south central South Dakota and pick up 10 and 13 which are 58 miles north, and channel 7 which is 59 miles south with 90-100 signal strength. Also a UHF channel 19 about 60 miles north. These antennas are at 50' which of course helps.

Cut channel 13 and separate UHF antenna pointed north with a 7777 amp. So I'm picking up channel 7 (NE PBS) off the back of these antennas with 90-100 signal strength.

However, I have a friend west of me that has an antenna similar to your grandma's mounted in his attic (no amp) that picks up these same channels. The signal strength isn't what mine is but they do lock in fine.

WRGB was digital rf 39 before the transition - I had a rough time getting the signal - they moved to rf 6 and reception is great. In fact 8 of my channels are VHF and I never have any problems with any of them. They are on the opposite side of a mountain - 30 miles away and all have strength in the 80s on my Dish receivers. The UHF stations on the same transmitter tower have more frequent drop outs. I had always though VHF hung better over mountainous terrain over UHF stations.

Originally Posted by CowboyDren

In RF theory, yes, VHF should be better (and was better for decades with analog transmissions). However, VHF and 8VSB is a provenly bad combination. Why do you think so many VHF channels are reapplying for UHF frequencies months after the digital transition? VHF vs UHF signal propagation shakes out to be about the same in the real world, if not actually favoring UHF in clear, flat terrain.

Do you have a comprehensive list of which stations VHF have reapplied for UHF, and which UHF stations have applied for VHF?

I don't particularly like 8VSB modulation, as it's not very good with multipath, but a good equalizer can deal with that. Can you show us some measurement data that 8VSB is worse at VHF? That would be quite interesting.

Originally Posted by wkomorow

I had always though VHF hung better over mountainous terrain over UHF stations.

That makes sense. But my grandma and I see a lot more amber waves of grain than purple mountains' majesty, ya' know?

Originally Posted by ericha

Do you have a comprehensive list of which stations VHF have reapplied for UHF, and which UHF stations have applied for VHF?

I don't particularly like 8VSB modulation, as it's not very good with multipath, but a good equalizer can deal with that. Can you show us some measurement data that 8VSB is worse at VHF? That would be quite interesting.

I haven't been keeping track, because my hometown has been all-UHF since before the transition. It's mostly anecdotal, but the DX guys are all hacked off about the problems with low-frequency 8VSB. I've just been watching the chatter and reports of stations either applying to move or at least colocating (9.2 is a SD feed of 29.1, 29.2 is SD feed of 9.1, etc) to compensate for lost coverage. A bunch of stations, VHF and UHF alike, all bumped or applied to bump the power even more after the transition because too many people at the fringe (50-ish miles) lost signal.

This kind of stuff doesn't affect most people, but the ones affected get seriously messed up. If grandma had a 50' tower, we would be having a different conversation.

Back on track, though, do you guys think it could be the balun, or am I barking up the wrong tree? It looks like an HBU44 would do the job, or a Y10-7-13 and a U4000, but I'm looking for a simple fix right now.

Originally Posted by CowboyDren

PS - Who the hell would take a perfectly good UHF station (14) and move it into VHF-Hi (13) for the transition?!?! It's like these broadcast engineers were trying to cut off viewers.

That's a common feeling, but in your case it's wrong.

VHF usually works better for outdoor antennas than UHF. UHF outperforms VHF when you use indoor antennas.

Originally Posted by Tower Guy

That's a common feeling, but in your case it's wrong.

VHF usually works better for outdoor antennas than UHF. UHF outperforms VHF when you use indoor antennas.

Why is that (UHF being better than VHF with an indoor antenna)? Is it because you can fit a higher-gain UHF antenna inside? For the same antenna gain, UHF should always be worse (since for the same gain the UHF antenna is smaller).