Illogical & Inconsistent Reception

[JusMe]

Very much a newbie in this area. I'll admit that I don't even understand the difference between VHF & UHF (and will wallow in my ignorance, as I honestly don't care about the difference - as long as it works!)

http://www.tvfool.com/?option=com_wr...f1f0248cd9778c

I only bother with late night news, and prefer CFRN Channel 3.1 (CTV network) but occasionally do catch some CBXT Channel 5.1 (CBC). If necessary, I'll see CITV Channel 13.1 (Global) but prefer not to. Particularly as only the first two mentioned here thus far provided decent reception.

I notice that the transmitters for both CFRN and CITV are on the same tower, or at least the same hill, 15 miles to the southeast of my apartment, which is in a high rise facing west-northwest, meaning that my own building is between me and the transmission tower.

I've tried three new antennas, and have returned all three, using an old cheaper Philips model from a few years back. The newer ones either didn't work at all, or provided no better reception.

Now, my real problem: I had the antenna set up to receive the CFRN signal for a few weeks - great. Suddenly, last night, I got "No Signal" from there, but another one, CITV, Channel 13, came in very clear. Seems I can get one or the other, but not both, and always one is there.

Doesn't make sense to me. Transmission is from the same place, but I can't get them both, but always get one or the other.

Any ideas about why this occurs? And more important, any idea of how I can get consistent reception of the CFRN signal?

[ADTech]

, meaning that my own building is between me and the transmission tower.

That's your problem.

With many modern high rises being made out of steel and concrete, if you are on the wrong side of the building, you're often out of luck. The signal cannot penetrate those materials with any predictability and you're usually left pinking up scraps of reception due to reflections which are quite unstable.

I'll admit that I don't even understand the difference between VHF & UHF (and will wallow in my ignorance, as I honestly don't care about the difference - as long as it works!)

You need to understand just enough to know that VHF, your channels 12 & 13, are VHF while the rest are UHF. When it comes to indoor antennas, adequate VHF reception is usually provided by "rabbit ears" and UHF is usually provided by a much smaller element.

I've tried three new antennas, and have returned all three, using an old cheaper Philips model from a few years back. The newer ones either didn't work at all, or provided no better reception.

There wasn't anything wrong with any of them (most likely), they just couldn't pick up that which wasn't there except as a ghost.

Suddenly, last night, I got "No Signal" from there, but another one, CITV, Channel 13, came in very clear. Seems I can get one or the other, but not both, and always one is there.

Could be any of a number of things. Indoor reception of VHF is subject to all kinds of issues which are only made worse due to your location in your building.

And more important, any idea of how I can get consistent reception of the CFRN signal?

The antenna needs to be on the opposite side of the building. With out that, it's going to be pot luck.

[JusMe]

Thanks, ADTech.

Let me get this straight - my CFRN and CITV are both VHF, but the CBXT is UHF? So I fiddle with the rabbit ears to adjust the first two channels, and only fiddle with the loop if something goes wrong with the reception for CBC?

Unfortunately, there's no way I'll get my antenna to the other side of the building, so I'm left with fiddling.

What really confuses me is that the two signals are coming from the same transmission tower and yet I can receive only one of them, but not both, and not neither. Any idea of how to get one consistently, rather than having to fiddle regularly back and forth?

[rabbit73]

Let me get this straight - my CFRN and CITV are both VHF, but the CBXT is UHF? So I fiddle with the rabbit ears to adjust the first two channels, and only fiddle with the loop if something goes wrong with the reception for CBC?

You have it right. The real channel numbers listed on your tvfool report determine what antenna is needed. VHF-High is 7-13. UHF is 14 and up.

What threw me at first was the virtual channel numbers, until I looked at Wikipedia. The virtual channel numbers on the tvfool report are wrong.
http://en.wikipedia.org/wiki/CFRN-DT

On August 31, 2011, when Canadian television stations in CRTC-designated mandatory markets transitioned from analogue to digital broadcasts,[10] the station's digital signal remained on VHF channel 12. Through the use of PSIP, digital television receivers will display CFRN's virtual channel as 3.1.

http://en.wikipedia.org/wiki/CBXT-DT

On April 1, 2011, CBXT began broadcasting its digital signal on UHF channel 42. On August 31, 2011, when Canadian television stations in CRTC-designated mandatory markets transitioned from analogue to digital broadcasts,[3] the station's digital signal remained on UHF channel 42. Through the use of PSIP, digital television receivers will display CBXT's virtual channel as 5.1.

Unfortunately, there's no way I'll get my antenna to the other side of the building, so I'm left with fiddling.

Yes, a lot of fiddling. As ADTech said, you are hunting for some useful reflections of your signals because the building is blocking the direct signals.

Now, my real problem: I had the antenna set up to receive the CFRN signal for a few weeks - great. Suddenly, last night, I got "No Signal" from there, but another one, CITV, Channel 13, came in very clear. Seems I can get one or the other, but not both, and always one is there.

What is happening is that the best antenna position for one channel is not the best for the other channel. If you get "No Signal" it means that the signal quality is not good enough for the TV to decode and on lock on, because the multiple reflections are causing too many errors in the digital stream to be corrected by the error correction system (FEC), and the signal falls off the "Digital Cliff" into dropout.

And more important, any idea of how I can get consistent reception of the CFRN signal?

I have doubts about "consistent," but there a few thing you can try for "better."

You can setup two antennas with an A/B switch. The location for the channel A antenna can be optimized. Then the location for the channel B antenna can likewise be optimized. When you switch channels, you switch antennas.

Your reception problem reminds me of a similar apartment building problem. Rather than repeating my thoughts here, please read through this thread:
Advice on Choosing an Indoor Antenna
http://forum.tvfool.com/showthread.php?t=15483

If the switch and two antennas doesn't work, the only thing I can suggest is to put a small UHF antenna in a metal trash can like Bill Naivar and Trip in VA did in the other thread and hunt for CBXT.

There is a Canadian forum that you might want to visit and present your problem. They are more familiar with the channels up there, but the multipath problems are the same there as they are here.

General questions
Over-The-Air (OTA) Digital Television
http://www.digitalhome.ca/forum/forumdisplay.php?f=81

Local areas
OTA Reception Results
http://www.digitalhome.ca/forum/forumdisplay.php?f=129

Your area
AB - Edmonton, Northern Alberta - OTA
http://www.digitalhome.ca/forum/showthread.php?t=108468

Please let us know if anything works for you on this same thread.

Best regards,
rabbit

[JusMe]

Thanks, Rabbit73. I'm understanding more and more!

As I only want the late night news, guess I'm best off just fiddling occasionally. Don't really want to mess about with two different antennas, one for each channel!

Thanks for your explanation.

Edit: Kinda wish we still had analog transmissions. I could manage the little I watch if there were ghosts or the occasional fuzzy screen. Oh well, that's progress.

[JusMe]

Update on what's been going on for me.

Got a Terk indoor open antenna to replace the Philips rabbit ears that had worked for 6~8 weeks, but then suddenly went black on me and wouldn't pull in anything, no matter how much I waved them about.

The Terk works fine, except that I've got to place it on the corner of my desk, which is just a little inconvenient, and means a cable running along the baseboard from the tv,

Got a new Digiwave 2080 with the intention of setting it up in the living room closer to the tv, with the idea that it would pull in the signal better.

Wrong - it worked poorer than the Terk, no matter how much I waved it about. So now it's got a new home in the closet - too much effort and postal costs to be bothered with returning it.

The Terk is giving me four of the six channels here, and I have no interest whatsoever in the two that don't show up, so seems this is the way I'll manage. Most I want really is the late night news, so ….

Strange that sometimes the tv shows a weak signal but clear picture, whereas other times it shows a normal signal but occasional cracking picture. Oh well, as long as I've got my news.