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Odd issue with reception (pleasant hill ca)

post #1 of 15
Thread Starter 
I live in pleasant hill ca. I'm receiving sacramento locals via a cm4221, and have good signal on all the local broadcasts. However, at 6pm I lose Kvie, and Kxtv. I understand both of these networks broadcast from the same tower, and on VHF. I also understand the cm4221 is a UHF antenna, but I'm able to view both channels, with 85-90% signal throughout the day. And when I say 6pm. it is almost to the second. Furthermore, at 6am. all channels come back with a strong signal. So, for 12hrs. I lose these channels. I contacted kvie via email, and this was there response to my question that I'm posting here, hoping for someone to shed some light on this matter.

I am sorry to learn that you are having trouble receiving the KVIE signal all the time. We are broadcasting at full FCC allowed power on VHF 9. The broadcast signal is not raised or lowered. It is the same 24 7. We are using the same tower as Channel 40 in Walnut Grove.

Our engineers recommend a regular UHF/VHF outside antenna. Are you having trouble with KXTV 10? Both KXTV and KVIE are now VHF TV stations while 3, 13 and 40 are UHF. Your antenna needs to be both UHF and VHF ready to receive all of the Sacramento based TV stations.

Are you running more than one TV set off your antenna? Using a splitter will drain away signal strenth even if the second set is not on.

We recommend one solid coaxial cable. Not cuts or repairs in that line.

If you antenna or cable are more that 20 years old it is time to replace them.

Viewers in out laying areas are finding that adding a pre amp to the antenna will help.

Hope this helps

If anyone can shed some light on this I would really appreciate it.
Thank you for taking the time to help.
post #2 of 15
Add a 5 or 6 element or a loop high-VHF antenna pointed at Walnut Grove via a UVSJ to the 4221 or swap the 4221 for a U/V combo as recommended by the engineers.

Trying to reliably receive VHF signals with a UHF antenna will often cause grief such as yours. It will work well enough when conditions are good enough, but will fail as soon as the atmospheric conditions change slightly. Daily variations in atmospheric signal propagation are common.

Install the correct antenna to fix the problem.
post #3 of 15
Originally Posted by korn858 View Post

However, at 6pm I lose Kvie, and Kxtv. I understand both of these networks broadcast from the same tower, and on VHF.

If anyone can shed some light on this I would really appreciate it.

In addition to the wrong antenna you could have FM stations that interfere with VHF. Try using an HLSJ as an FM trap. (Leave the L port blank, use a 75 ohm terminator, or connect it to your FM receiver.)
post #4 of 15
Thread Starter 
I will try a VHF antenna, and see if that fixes the problem. I double checked again last night, and this morning; at 6pm. signal vanishes within seconds, and at 6am. signal comes back within seconds.

Thank you both for your input.
post #5 of 15
Even though you are able to receive those two VHF stations with your UHF antenna, perhaps your signal strength for those VHF stations is low, perhaps barely above the minimum signal threshold for your tuner to decode the signals. VHF also tends to be more susceptible than UHF to interference from nearby electronics, microwaves, lightning and other sources.

Since you report that you are repeatedly losing and regaining these two signals at 6pm and 6am respectively, perhaps there is some kind of electrical event in your vicinity (perhaps on a timer of some kind) that is becoming active at 6pm and knocking out your signal until 6am, when that event stops. One possibility could be nearby outside light timers (either yours or a neighbor's).

In any event, adding a dedicated VHF-high antenna to your 4221, and joined with a UVSJ, should increase your signal strength on those two VHF stations so that they overcome whatever local interference you might have.
post #6 of 15
Originally Posted by korn858 View Post

at 6pm. signal vanishes within seconds, and at 6am. signal comes back within seconds.

Thank you both for your input.

Armed with that information I'd say that some electrical equipment starts automatically and is interfering with VHF reception.
post #7 of 15
Thread Starter 
Ok, get ready to laugh. Tower Guy, and gcd0865, you got me thinking about something electrical on a timer, and guess what? My neighbor has a shed, right in the line of the signal coming from that tower, and he/she are growing pot in there. Grow lights on at 6pm. off at 6am. LOL. Now, do you think it would be easier to move my antenna away from that side of the house away from the shed, or do you think a VHF antenna would be able to deal with the interference? Or, any other advice you can offer as far as some sort of filter?

Thank you again everyone for all your help.
post #8 of 15
Talk to them about the interference. Ask them to help to resolve your issue.
Perhaps, not only will they/he/she be receptive, but also compensation will could be rewarding.
post #9 of 15
Thread Starter 
Ratman you are on to something here. I've been pulling my hair out for over a week with this. I couldn't tell you how many trips up and down the ladder I've made. Perhaps some "compensation" is in order; I know I've earned it. I've ran new Quad 4 cable, new ends, rotated the antenna all over the place, and now I'm sitting here laughing.
I'm thinking the best and easiest solution will be to move the antenna tho. My neighbors and I don't really talk too much, and I think if I try and bring up the fact there pot farm is interrupting my Charlie Rose, and Frontline, well it would be awkward at the least. I only know about the pot, because I get strong wiffs of it on occasion.
post #10 of 15
Thread Starter 
Alright, this problem is officially over! Relocated antenna, and my signal is steady as can be.

Thank you all very much for your input, and all your expertise.
post #11 of 15
Hey, this is funny! One more thing to ask our callers about!

From the Department of Coincidences:


DTV Reception 24 7

by Charles W. Rhodes, 04.05.2011

The first time I received an e-mail about DTV reception only during daylight hours, I was dubious. More recently, a reader in Humboldt County, Calif. wrote that reception in his town folds at sundown. He wrote that "grow lamps" are automatically switched on in many homes then. Those fluorescent lamp fixtures have solid-state ballasts that generate and radiate a lot of noise that falls within the low-band VHF channels. There's a local station on Channel 3 there. He also explained that there's a thriving agricultural industry in growing marijuana plants for fun and profit in the county. This man-made noise problem is fairly minor today, as there are only 38 low-band VHF band full power stations still in operation.


Other reports have trickled in so I've given some attention to other possibilities.

The full article is posted at http://tvtechnology.com/article/117368

I showed this thread to the boss. You'll likely see some mention of it (or the subject, at least) in a future blog post of his.

post #12 of 15
That's rather amazing; glad to hear it worked out...
post #13 of 15

Korn858, I realize you haven't posted on this in 2 1/2 years but hoping you will still get this..... I recently moved to pleasant hill and I am trying to set up my antenna. Its a CV2. I haven't been able to get more than 10 channels and have moved it all over my roof. Any advice you can give me!?!?!?


Thanks for your time

post #14 of 15
I don't think he is going to reply. His last post was 2 1/2 years ago.

You are most likely to find the help you need if you post in the San Francisco or Sacramento threads of the forum above this one depending on which stations you are trying to receive.

FWIW the CV2 is a UHF antenna, so write off the VHF stations. The range isn't all that great either. You may need more antenna, and a rotor, or even multiple antennas to get what you want. And it is still going to be iffy with all the hills around.
Edited by Colm - 10/21/13 at 10:16pm
post #15 of 15
FWIW the CV2 is a UHF antenna, so write off the VHF stations.

You are confusing the C2V with it's predecessor model C2. The C2V has been around for about two years.

The C2V has a VHF dipole strapped on the back which is likely to be effective out to a max of 25-35 miles on VHF, depending mostly on the local VHF station's power level and the individual signal path. Personally, I've used it out to about 55 miles, but I cheat with my Sencore handheld spectrum analyzer. biggrin.gif
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