No Digital Signal ?

[TxDoc]

I am in Texarkana, TX 75503. I have a 70 foot mast with a Windgard 7967
HD7697P & HD7698P (VHF, UHF) Channels 7 - 69

All four networks-ABC, NBC, CBS and FOX are at approximately 170 South of me. I have tried three different amps, three different converters, moved the antenna slightly to try to adjust for best signal...and still find no channels and a zero signal. I have lowered the antenna to recheck connections, also.

The analog channel for channel 3 is still transmitting a PSA on how to hookup your converter box. I get this signal just fine.

Even the station engineers are baffled.

Any help is appreciated.

[KNP 2516]

http://www.tvfool.com/index.php?option= ... &Itemid=90

You have a station 4 1/2 miles from you.
Interactive TV Coverage Browser

KZTE-LP 45 (64.1)

Max ERP: 1.000 kW
Eff. pwr: 1.000 kW
Dist: 4.5 mi Path: LOS
Rx: -45.9 dBm NM: 45.1 dB
Az: 154.5° (true)
Az: 152.0° (compass)
Map data ©2009 Tele Atlas - Terms of Use



Callsign Chan Network Dist
(mi) Path NM
(dB)
KTAL-DT 15 (6.1) NBC 42.1 LOS 49.7
KZTE-LP 45 (64.1) 4.5 LOS 45.1
KTBS-DT 28 (3.1) ABC 57.6 LOS 35.1
KMSS-DT 34 (33.1) Fox 59.0 LOS 32.1
KSLA-DT 17 (12.1) CBS 58.4 1Edge 21.3
KSHV-DT 44 (45.1) MyN 59.0 1Edge 18.2
KPXJ-DT 21 (21.1) CW 57.6 1Edge 14.2
KLTS-DT 24 (24.1) PBS 58.3 2Edge 12.1
KETG-DT 13 (9.1) PBS 63.9 2Edge 10.2
K63BA 23 (63.1) 48.2 1Edge 7.2
KJEP-CA 23 (23.1) 35.9 LOS 0.8
*KLTV-DT 7 (7.1) ABC 92.5 Tropo -8.8
KKYK-DT 49 (49.1) Ind 82.6 Tropo -11.1
KTVE-DT 27 (10.1) NBC 112.4 Tropo -12.4
KCEB-DT 51 (54.1) CW 98.9 Tropo -13.7
KETS 7 PBS 126.9 Tropo -14.3
KTHV-DT 12 (11.1) CBS 129.0 Tropo -15.0
KETK-DT 22 (56.1) NBC 121.7 Tropo -15.4
KFXK-DT 31 (51.1) Fox 98.9 Tropo -15.5
KEJB-DT 43 (43.1) MyN 112.6 Tropo -15.5
KVTH-DT 26 (26.1) Ind 85.8 2Edge -16.4
KARK-DT 32 (4.1) NBC 129.0 Tropo -16.6
KYTX-DT 18 (19.1) CBS 124.1 Tropo -16.7
KTEN-DT 26 (10.1) NBC 153.0 Tropo -17.0
*KARZ-DT 44 (42.1) 129.0 Tropo -18.4
KKAP 36 (36.1) Ind 129.2 Tropo -18.7
KLRT-DT 30 (16.1) Fox 129.4 Tropo -18.8
KARD-DT 36 (14.1) Fox 148.1 Tropo -19.5
KHBS-DT 21 (40.1) ABC 113.3 Tropo -19.8



About the signal strengths and coverage overlays

- They DO take into account the transmitter power, frequency, antenna pattern, and height
- They DO account for propagation losses due to terrain
- They DO account for curvature of the Earth
- They DO NOT take into account your antenna gain, amps, or receiver sensitivity
- They DO NOT account for building obstructions or indoor penetration
- They DO NOT account for multipath

Just by looking at your signal coverage maps, I would guess that you are too close to some of the stations and that one or more of the local stations is interfering` with all the others.

There is a theory - where you can be too high.

You have to forget about VHF technology and start thinking in UHF Digital terms.

[KNP 2516]

Read this

http://www.hdtvprimer.com/ANTENNAS/siting.html

http://www.winegard.com/kbase/kb_tip_re ... ip_num=354

http://en.wikipedia.org/wiki/Radio_propagation

http://www.hdtvprimer.com/ANTENNAS/basics.html

[KNP 2516]

The only thing you did not change was the wire.

All cable has loss and the higher up that you go in frequency (VHF to UHF)
the more loss that the cable has.
If you start with a low level signal at the antenna and then butt it into
coax cable you are going to have less come out at the end than went into it
from the antenna. The amount of loss depends upon a number of factors,
cable type and cable length are the two most important. Cable is rated in
db loss per 100' at X MHz (frequency). RG-6 cable is the cable most used
in TV use. Like all things there is good RG6 and not so good. Belden
1829AC Coax - Series 6 has a loss of 4db/100 feet at 500 MHz (TV Channel
18)
Channel 32 is 580 MHz Channel 52 is 700 MHz a 5 db loss At TV channel 2
the cable would have a loss of 1.4db. So at channel 18 you loose more than
1/2 the power in 100' of cable between the antenna and the TV.

An amplifier is an amplifier

The best is to only use a amplifier as close to the antenna as possible
with the highest gain in the area that you are interested in receiving
(UHF) with the lowest possible noise and both at a reasonable cost.

The KEY is that you want a relative "good" level of input at your receiver
(TV) with the minimum noise.
A mast mounted amplifier (doesn't matter if it is called a amplifier or
preamplifier) is the best when you are in a remote area.
In theory it is best if you amplify a "good" signal to a higher level than
a "poor noisy" signal to a higher level. When you start out with crap and
amplify it you just end up with more crap.

I would also look at the splitters you are using.

All splitters by nature has a loss of no less than 3 db per a connection.

The only splitters good for over the air television in a marginal area are ones with at least 1000 Mhz rating and 2 outputs.

Multiple output splitters has a loss as much as 7.5 db per a output, the outputs are not equal so one or more outputs may be ok and then the others might have so much loss that you loose most of the tv signal in the splitter.

Remember 3 db = a loss or gain of half or double for a signal.

http://www.hdtvprimer.com/ANTENNAS/basics.html

20 dB = gain factor of 100

10 dB = gain factor of 10

3 dB = gain factor of 2 (actually 1.995)

0 dB = no gain or loss

-1 dB = a 20% loss of signal

-3 dB = a 50% loss of signal

-10 dB = a 90% loss of signal

[KNP 2516]

If you want advice about a steak, you go to a butcher.

If you want advice about antenna's - you go to a ANTENNAMAN!