Very Low signal strength acquistion
This is a discussion on Very Low signal strength acquistion within the DTV | HDTV Reception and Antenna Discussion forums, part of the Over-the-Air (Antenna TV) category.
Very Low signal strength acquistion
My Signal Map TV Fool
As you can see, I have some pretty low levels I am going after. So I know I am going to need both a decent Antenna as well as a pre amp. My question is what is the threshold that is reasonable to go after. I would like to be able to receive NBC which currently sits at -115dbm (dtv.gov puts it at -90dbm) but before I spend too much effort, I would like to know how feasible this is.
This is a vacation home, which will only have one TV. My plan would be to run a ~50ft RG-6 run straight from the TV to the antenna (roof or tree mounted) through a pre-amp. I was planning on using a 60 mile antenna like WINEGARD HD 7084P TV Antenna and a channel master 7777 preamp.
Has anyone tried to pick up a signal this low, and if not what is the lowest reasonable strength to go after?
Chief Content Editor
I receive a station 76 miles away with a (theoretical) field strength of 69.2 dBm and I split it 4-ways around my home without using any amplifiers. I tested at least seven different antennas at a variety of heights and I never got so much as a blip. So, I decided to build my own cut-to-channel Yagi which I call my "Project-35" and it can be seen in my albums here on the Forum. It is the only antenna that receives KVOS here and it was well worth the work to build. We enjoy MeTV and TheCOOL TV from that station.
On the same transmitting tower located about 80 feet lower and with lower power is a second antenna for "The Shopping Channel" @ 75 dBm and it has 'blipped' in occassionally, but it is not dependable nor do I care to receive it so I haven't put any special work into trying to receive it.
Another channel (which went dark last year) was an analog translator (repeater) we received pretty well @ 76.4 dBm and we miss it.
Another translator that has blipped in and out is @ 103 dBm and I feel pretty certain I could capture it, but it would take a lot of work. It would be a duplicate, so we don't need to receive it.
What I'm saying, is your TVFOOL and dtv.gov reports are theoretical: they do not take into consideration the actual terrain between you and the transmitters, so what looks impossible may work ... or ... the other way around. Your NBC station is a full-power transmitter and its only about 60 miles away from you, which are to your advantage. KVOS mentioned above has 560 kW output rather than 1 mW, so it has about 3 dB lower power to begin with and its 15 miles farther away.
The antenna you chose is not particularly well suited to receive WJAC-DT (34) at that signal level, but the CM-7777 is a good choice for a pre-amp. I suspect you will need to build an antenna very similar to my Project-35 or possibly two of them to be ganged together (stacked). If that sounds interesting to you, I can offer some simple techniques to build one or more and the cost will be about twenty dollars in materials.
Also consider, addititional antenna height usually helps, but you might find a signal is present much lower, even on the ground (ground waves).
If you aren't willing to build an antenna specifically designed to receive that one channel, an option would be to try an antenna like a Winegard HD-9095, which is an 'all-band UHF-only' (compromise) antenna. Unlike the antenna you suggested, it does not have VHF elements that you don't need.
Winegard HD 9095P UHF Yagi Style HDTV TV Antenna (HD9095P) from Solid Signal