Warm weather= 57 channels, Cold Weather= 2 Channels!?

5

50AmpFuse

DTVUSA Member
#21
#21
Guest said:
I live in Ar. & we have the same problems when the temp drops bellow about 38 degrees we lose all but two of our stations
Click to expand...
Sounds like we have the same exact problem! The channels start dropping-off right around 40 degrees, then return in the morning, just like yours! Very frustrating! My friend's antenna is not effected by rain or wind either so it makes me think that moisture has nothing at all to do with it but I will check & redo all RG6 connections anyway.
Here, at my house, I use a home-made Greyhooverman double bay (Copper) pointed towards the same exact transmitter as hers, and mine is about 15 miles further away! The low temps have absolutely no effect on mine though... that's why I'm thinking it's her Aluminum U4000 antenna. At first, I thought maybe it was interference from her Heat Pump unit since that would be running when it's cold, but it has no effect at all. I have already ran a dedicated circuit for the TV & converter box to try to illiminate any chance of iterference from something else on the same 120V circuit.
 
dkreichen1968

dkreichen1968

Moderator
Staff member
#22
#22
50AmpFuse,

I'm wondering if it has something to do with the amp. Could you try it without the amp? There should be enough signal for most of those channels if they're only using one TV.
 
5

50AmpFuse

DTVUSA Member
#23
#23
dkreichen1968 said:
50AmpFuse,

I'm wondering if it has something to do with the amp. Could you try it without the amp? There should be enough signal for most of those channels if they're only using one TV.
Click to expand...
I had tried it without the amp a few months ago & only recieved a few channels. (Much like when it's cold!) I never changed any factory setting for the "FM trap". It is supposed to be set to "IN" from the factory... I have to admit, I don't know what that is! Could this be a problem?

If re-doing all the connections doesn't fix the problem, I can try "swaping" the amps and see if the problem happens here. If it happens here, the amp is definitely the problem.
 
dkreichen1968

dkreichen1968

Moderator
Staff member
#24
#24
I have a feeling the amp may be having problems with the cold. I'd think based on the TVfool that there wouldn't be any need for an amp, which makes me wonder about the cables... But, you can never seem to tell.
 
5

50AmpFuse

DTVUSA Member
#26
#26
OK, I just replaced the CM7777 Amp with a new 7777 today. There were no signs of any moisture in the connections and all of the "stinger" wires in the RG6 were nice and long!
I also replaced the baluun while I was up there! The temperature was in the 50's when I finished and it scanned 61 channels. The temps are supposed to drop quickly so... I'll be waiting for her to call me with an update as soon as it drops below 40 degrees. Now that I have her "old" 7777 amp here, I can test it by exchanging it with mine.
...to be continued...
 
5

50AmpFuse

DTVUSA Member
#28
#28
Inside the CM-7777

Out of curiosity, I opened up the cm7777.
I'm no longer interested in why it didn't work in the cold...now I just want to know what a "Self-Excitaton Quarantine Area" is!?!?!? :eyes:
CM-7777 001.jpg
 
Tim58hsv

Tim58hsv

DTVUSA Member
#29
#29
That's the inside of the new CM7777 and not the old one which had separate inputs for VHS and UHF antennas.

Are you sure the problem was with the preamp and not the balun, which you said you changed also? Was it an outdoor balun or not? What type of balun was it exactly?

Thanks.
 
5

50AmpFuse

DTVUSA Member
#30
#30
You are correct, I did change that also, so I guess I can't be 100% certain it was the pre-amp. The old one came with the antenna... it was only marked "Matching Transformer 2011-09-01". I have no idea if it's supposed to be for outdoor use or not, but it looks much cheaper than the new one. The new one was from Radion Shack #15-1230
transformer 001.jpg
 
5

50AmpFuse

DTVUSA Member
#31
#31
Tim58hsv said:
That's the inside of the new CM7777 and not the old one which had separate inputs for VHS and UHF antennas.

Are you sure the problem was with the preamp and not the balun, which you said you changed also? Was it an outdoor balun or not? What type of balun was it exactly?

Thanks.
Click to expand...
I should have replaced them one at a time in order to be 100% certain. It wasn't below 40 when I did the repairs so changing only one of them wouldn't have made any difference (while i was there). I'll test both "old" parts here at my place when it's nice and cold. I'll let you know.
 
Tim58hsv

Tim58hsv

DTVUSA Member
#33
#33
Definitely an outdoor balun which still could have been the problem. Just because water didn't drip out of it like mine doesn't mean that moisture didn't get inside of it.

On the other hand the new CM7777 preamp isn't getting all glowing revues on Amazon with several reviewers saying that there's died soon after purchase. Thing is, don't toss the amp out until you're sure it's the problem.
 
dkreichen1968

dkreichen1968

Moderator
Staff member
#34
#34
Personally I can't imagine the balun causing the problem. It's a pretty robust piece of equipment that shouldn't be effected by temperature. But, the amp... Yes, PCB and IC electronics, especially cheap Chinese PCB and IC electronics, can certainly be effected by temperature. That's what my money is on.
 
5

50AmpFuse

DTVUSA Member
#36
#36
Update: I haven't had time to test the old balun or CM7777 yet but since I replaced them, her Antenna has been working 24-7 with the temps well below 40!

:dancing:
 
highdefjeff

highdefjeff

Contributor
#38
#38
Jim5506 said:
Check the stinger length (center wire) on the cable at all couplings, if it is too short, it will lose connection in cold weather when the copper core contracts, could be the problem.
Click to expand...
Even though it was the balun this time, I would always check connections for tightness, needle length, and stray braid or foil near the center conductor in cold temperture fade.
 
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5

50AmpFuse

DTVUSA Member
#39
#39
highdefjeff said:
Good to know it is the balun.
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Actually, I was saying I still don't know for sure if it was the Balun or the CM7777 since I have not tested the "old" ones yet. Normally, I would have tested them both right away but I've been overwhelmed with work for the last 3 months (I'm an electrician). I will though & I'll let you know! :eek:)
 
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