Join Date: Aug 2009
Location: Beaverton, Oregon
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First of all, with marginal signals, TV tuners vary. One tuner will decode what another tuner cannot. I have two set-top boxes and a TV set in my lab. hooked up to the same antenna and with the same signal amplitude. With marginal signals, the TV set and one of the set top boxes will often not decode signals the other set top boxes will.
Be aware that with DTV, if the set can decode the signal at all, the picture is likely to be perfect. There is a very narrow zone when the signal will pixilate and the sound will break up so this rule is not absolute. This feature of DTV often makes trouble shooting reception problems very difficult. You can be sitting on the very edge of decoding failure and not know it.
As for the stations you mentioned, KUNP-LP transmits virtual channel 47.x on RF channel 34. I am ~9 miles from the station and my records show it's amplitude has been essentially constant for weeks. Signal reception can vary if the transmitter starts distorting (not likely, but possible) or if the trees and growing stuff in the path vary the path loss. At my close in site, I have seen 1 or 2 dB of signal increase as the leaves fell off of the trees (at least I think that's the cause). Also, storms apparently causing wet trees to wave in the path can cause decoding problems. Even at my close-in site I have sat and watched the signal amplitude of the local DTV stations vary several 3 or 5 dB as the wind blew. In marginal conditions, a 1 or 2 dB change can cause signal loss. I'm a little surprised that you can receive this signal in Salem. The coverage maps show the signal is pretty iffy there.
You also mentioned ch. 41 and ch 15. KOXO-CD used to be on RF41 and used a virtual channel ID of 41.x. Many months ago, it moved to RF channel 15 but continued to use the virtual ID of 41.x. In mid February it dropped that ID and used an ID of KOXI-CD virtual 20-1. (To add to the confusion, at the same time, the actual KOXI-CD RF ch. 20 using a virtual 20-1 was also transmitting). Checking this morning, I note that the transmitter on RF 15 is now IDing itself as KORS-CD virtual 16-1 (it should be using the call letters KOXO-CD). Using the wrong call letters is very odd and I assume it is part of the off the air too long problem I noted that the WatchTV stations have in my 2/18/19 posting to this site.
I am completely baffled by your mention of 38.1. That one I don't know.
Last edited by LinleyG; 02-22-2019 at 11:07 AM.
Reason: Removed excess number of line feeds.