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preamp/powersupply question

post #1 of 9
Thread Starter 
I just added a Winegard YA 1713 to my array in the attic which includes a CM4228 and a CM 7777. I was in hopes that I would be able to lock on channels 7 and 9 which are 73 miles from my home. I can now get a lock but have occasional dropouts. I put the power supply in in the attic about 3 feet after the preamp because I assumed the power supply sent the signal down the line to the tv. Was I wrong? should I have put the power supply closer to the tv 40' away?
post #2 of 9
Pre-amp power supplies supply DC power to the pre-amp. The power supply location is not important, however I believe that the best location is downstairs. Generally, I do not like to have active devices in the attic.

I also believe that if you are going to have a chance of reliabily receiving TV stations 70 miiles away you are going to have to move your antenna outside and as high as possible off the grond.
post #3 of 9
Thread Starter 
Quote:
Originally Posted by sptrout View Post

Pre-amp power supplies supply DC power to the pre-amp. The power supply location is not important, however I believe that the best location is downstairs. Generally, I do not like to have active devices in the attic.

Downstairs because of the threat of fire?

I also believe that if you are going to have a chance of reliabily receiving TV stations 70 miiles away you are going to have to move your antenna outside and as high as possible off the grond.

Pre transition, except for NBC, I received all of the major networks and about 6 other stations reliably at 70 to 75 miles from the towers. After the transition, I lost abc and cbs because they were moved to 7 and 9 vhf. So I have just added the yagi to try to regain the signal. I really want to keep the antennas in the attic, my signals are almost strong enough to be satisfactory. I just wondered if moving the power supply closer to the tv might help. I'm also wondering if setting the FM trap to out might also help.
post #4 of 9
Yea, I don't like active devices in the attic because of fire issues, but in this case there is no reason to. The power supply location has no affect reception so installing downstairs is fine. The most important thing to remember about pre-amps is that they must be mounted as close to the antenna as possible. You want to keep the cable losses between the antenna and the pre-amp to a minimum. If you have more than a few feet of cable between the pre-amp and the antenna, move it next to the antenna.

I do not think FM traps will make any difference. My pre-amp has an FM trap and I cannot remember if I switched it in or not, but I am only trying to receive stations that are ~30 miles away.

In addition to distant (miles) losses, VHF is very prone to weather/lighning interference. So I think at best you are going to have very unreliable reception unless you live in an area that does not have storms.

VHF is very prone to interference of all kinds so a pre-amp may not be of any help. It may be just a noise amplifier since you will have very weak desired signals.
post #5 of 9
Thread Starter 
I have the preamp only about a foot or so below the 4228. I don't have the height in my attic to get the yagi much more than a foot below the 4228, so I had to locate it 13 feet away on the other side of a dormer. There is probably about 16 feet of coax between the yagi and the preamp. How much of the signal do you think I might be losing because of this?
post #6 of 9
I do not recall the loss per foot of standard coax, but 16' should not be much. However, any signal loss between the antenna and the pre-amp is not recoverable.

Just curious, were you able to receive any 70 mile+ VHF channels before the switch to digital? How about UHF?

The more I think about it, I just do not see you having any luck trying to reliabilily receive any stations from that far away without moving your antenna outside, and up. Even then I think VHF will be a crap-shoot based on the experiences that I have read about here on this board and other places.
post #7 of 9
Thread Starter 
Quote:
Originally Posted by sptrout View Post

I do not recall the loss per foot of standard coax, but 16' should not be much. However, any signal loss between the antenna and the pre-amp is not recoverable.

Just curious, were you able to receive any 70 mile+ VHF channels before the switch to digital? How about UHF?

The more I think about it, I just do not see you having any luck trying to reliabilily receive any stations from that far away without moving your antenna outside, and up. Even then I think VHF will be a crap-shoot based on the experiences that I have read about here on this board and other places.

I'm in Orange, Virgina trying to receive Washington DC stations. Before the switch, I was able to receive UHF reliably at 70+ with the 4228 and 7777 in the attic. I received no VHF at that time. Pre transition, WUSA 9 and WJLA 7 were UHF and just about 100% reliable, but after the switch they both moved to VHF. I was then able to view them only on rare ocassion with the 4228, so I puchased the YA1713.

Yesterday at around 5pm, there were severe thunderstorms between me and DC, and 7 and 9 were pixelating and dropping out almost constantly. An hour or so later, they were solid the rest of the night.

I'm pretty close to getting these two, now VHF stations, reliably and hope a few tweaks will get me there.
post #8 of 9
Yea, I can see your VHF channels getting hammered by storms. I think whatever you end-up doing that you will have to live with storm interfence. I have storm problems on my VHF channels and I am only 30 miles from the transmitters and show 100% on my signal meters during normal conditions.

I do not have any other suggestions. There is really not much you can do with signal levels that are down in the mud. One thing that you may want to check is to make sure that the D.C. stations have completed their cutover process. Here in Houston, stations are still making changes to their antenna systems that they could not start until after their analog transmitters were turned-off. One VHF station (11) got their ERP cutback consideraby by the FCC and they are having a difficult time covering the Houston area. Maybe the D.C. stations are still in the middle of their cutovers??????
post #9 of 9
Thread Starter 
That may well be the case, I'll have to check in to it. There have been a lot of complaints from people not being able to receive 7 and 9 since the transition, even those in close proximity to the transmitters.
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