Loss of leaves=no signal?

chum1976

DTVUSA Jr. Member
#1
In the early summer I installed a 91XG antenna plus a channel master booster. Since the leaves started falling I cannot receive my local PBS station 3.1 and I cant figure out why. Every other channel comes in at 100% but the PBS was the weakest at 40%. I have included my TVfool report below. I watch the PBS stations the most and last Friday the signal died...0%. Other people I know can still get it so its frustrating. Any suggestions would be great. Thanks!

TV Fool
 
#2
Are you using a rotator? The absence of leaves on the trees has probably changed the signal patterns your antenna was used to seeing during the summer months. I would first experiment with height & aim adjustments to get the antenna back in a sweet spot for PBS 3.1. I also find that tilting up the front of the 91XG can improve reliability of marginal signals, so you may want to give that a try as well.
 

chum1976

DTVUSA Jr. Member
#3
Thanks for the reply. I had a friend over today and we tried moving it to no avail. I already had the front tilted up which really helped when it was first installed. I have a old BUD in the yard maybe I can convert it to FTA....any advice on that? ;)
 

Fringe Reception

Super Moderator, Chief Content Editor
Staff member
#6
Chum,

Your TVFOOL report doesn't suggest any reason you shouldn't be able to receive a dependible WPSU 3.1 (15) especially at 25 feet of antenna elevation, unless there was a change at the transmitter/antenna.

Since this is a seasonal change noticed when the leaves left the trees in your area, my first thought is you may now be collecting more signal or noise than before, possibly including increased multipath signals that the trees had been attenuating for you. If so, the signal and or noise levels may now be too strong for your receiver to decypher and reassemble into a picture and audio.

Also, all pre-amplifiers and distribution amplifiers add their own noise to an RF signal, so an increased noise level by nature, plus amplifier noise may be the problem.

Have you tried to receive your stations, bypassing the CM amplifier? The reason I ask is because what you said: all other stations come in at 100 on your 'meter'...

Although it may seem counterintuitive, in the digital OTA world a clean, low-strength signal often trumps a strong signal. Example: I split a 1-edge signal 4-ways around my house from a 300 watt analog translator located about 40 miles from me using NO amplifiers at all.

I hope this helps and please keep us posted.

Jim
 

chum1976

DTVUSA Jr. Member
#7
Hi,

I just unplugged my amp and lost all channels except 10.1 which was 24%. I emailed them, but havent heard back. I will try your suggestions tomorrow. Thanks
 

Fringe Reception

Super Moderator, Chief Content Editor
Staff member
#8
Chum,

Did you physically remove it from the antenna circuit? (as in bypassing it using a double-female F fitting?) A non-powered amplifier is a major signal attenuator: virtually no signals get thru it.

Jim
 
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MrPogi

Moderator, , Webmaster of Cache Free TV
Staff member
#9
Do any other OTA users near you have a problem, or have they noticed any change in signal, with this station?
 
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Chips

DTVUSA Member
#10
WPSU has been in the process of making numerous changes to it's transmitters. They appear to either have or are in the process of installing a translator on the same frequency Ch. 15 in their market and changing the signal pattern of their main transmitter. How far along they are in the process or if they have hit a problem remains to be seen. Here is the FCC page for WPSU
TV Query Results -- Video Division (FCC) USA
Here is the page for the FCC applications for WPSU
Application Search Results
It could be that their transmitter is down while they work on it. It could also be the fact they they are running a translator on the same Ch.15 and if you in the right locations you are picking up both Ch.15 which would cancel both signals. I suspect the transmitter may be down, the only way to find out is to contact them, as you have done. Depending where you live you could be affected by the change in their transmitter directional pattern. Sorry I can't give an answer. You may also want to look at Trip Page. RabbitEars.Info
click on listing and type in the box WPSU, I believe Trip shows the new signal patterns for WPSU on that page.
 

Chips

DTVUSA Member
#12
There's nothing new about it. They've been running that on-channel booster for YEARS under experimental authority (since 2003 maybe?). They're only just now licensing it.

- Trip
Thanks Trip,
I appreciate your web site and the information.
I was under the impression that the application to change their main transmitter signal pattern was new. Depending on where you live, that could have an affect on your reception. I could often pick up WPSU for few hours when the Trop is right.
 
#13
Chum,

Your TVFOOL report doesn't suggest any reason you shouldn't be able to receive a dependible WPSU 3.1 (15) especially at 25 feet of antenna elevation, unless there was a change at the transmitter/antenna.
I must be missing something.

A noise margin of -11.8 with a 91 XG with a gain of 11 dbi and a good preamp with a 3 db noise figure nets a system NM of -3.8. That should not have worked in the first place.

The on-channel booster seems too far away to be received.

The best antenna for channel 15 is the HD-8800. It has a gain of 14 dbi on channel 15.

http://www.hdtvprimer.com/ANTENNAS/comparing.html
 
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dkreichen1968

Moderator
Staff member
#14
TV Fool

How would you explain me pulling in KRMA (real channel 18) with an unamplified loop antenna? That shouldn't work either. It just proves that TVfool is just a guide. Getting a higher gain antenna may be the solution, but it's kind of a shot in the dark.
 
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#15
TV Fool

How would you explain me pulling in KRMA (real channel 18) with an unamplified loop antenna?
TVfool uses two dimensional terrain calculations. In extreme terrain such as Colorado the bounce off the side of a mountain is often stronger than the refraction over the top. The loop is better at finding the optimum path than a directional antenna without a rotor.
 

dkreichen1968

Moderator
Staff member
#16
Just proves that TVfool doesn't take everything into account. I have to believe that all of my Denver channels are much stronger than TVfool predicts. Except for KBDI (real channel 13), which is extremely weak in my area even though it shows much higher on TVfool. It broadcasts from Squaw Mountain while everything else comes from Lookout Mountain. I have a translator to the south of me, so I don't need to worry about getting KBDI from the north.
 

chum1976

DTVUSA Jr. Member
#17
I must be missing something.

A noise margin of -11.8 with a 91 XG with a gain of 11 dbi and a good preamp with a 3 db noise figure nets a system NM of -3.8. That should not have worked in the first place.

The on-channel booster seems too far away to be received.

The best antenna for channel 15 is the HD-8800. It has a gain of 14 dbi on channel 15.

Comparing some commercially available antennas
Ok, I will order this and try it. Thanks for all the help
 
#18
Please let us know your findings with the 8800. I have tried the Winegard in 3 different environments (metropolitan, suburban & deep fringe) and the 91XG won hands down each time on the entire UHF spectrum.
 

chum1976

DTVUSA Jr. Member
#19
Please let us know your findings with the 8800. I have tried the Winegard in 3 different environments (metropolitan, suburban & deep fringe) and the 91XG won hands down each time on the entire UHF spectrum.
Hey I tried it and you were right......no signal. The other channels signal was lower with the 8800 than the 91XG. The 8800 was so cheaply made it would not have lasted the winter, and it was all bent up like it was tried once before. Amazon is giving me a full refund so it was worth the try.
 
#20
I agree & also feel the 8800 is flimsier than the 91XG.

One question for you about the 91XG though. Is the stationary element right in front of the balun straight or bent into a weird position. The first 3 I bought were bent into a weird shape, but the newest one I have is straight across. It seems to work fine bent, but now I'm wondering which is correct?

Thanks in advance!!

By the way, you never mentioned which model Channel Master amp you are using?
 
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