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Old 28-Aug-2017, 3:19 PM   #1
BarberSurgeon16
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Please Advise: Weak Signal, even woth trying more?

Friend has moved location and previously had dish. Was interested in OTA, so I said I would bring over my basic Hoverman-Grey and my cheapy amp to see if we could get anything. Ran from existing roof mount, @25ft above ground.

No channels came up on search. Antenna pointed to try to pull in Fox and At least CW between 250* and 260*.

Location is at bottom of a hill, and there are trees. I figured if we could at least get CW, I might try a different amp or add a reflector to my antenna to try to pull is something additional. At my house I can get all the stations out of richmond, with an attic mount my line of sight is much better, and better signal over all.

So here's the location search results:

http://www.tvfool.com/?option=com_wr...e6a4f472e6c14d

Was thinking of a Channelmaster Signal amp, possibly could get another 5 feet up with another mast and mount improvements. When Analog broadcast was OTA, they got most of the richmond networks at this location.

If nothing I do is going to get a usable signal here, I'd rather not waste time and money for no return.
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Old 28-Aug-2017, 4:27 PM   #2
rickbb
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You're going to need a giant antenna first. This location is so far away from all the transmitters you aren't getting enough signal to try an amp yet. All you would do it amplify the noise along with any signal.

That was usable back in the analog days, you'd just have a picture with snow and lines. But now with digital tuners they see all that noise and just refuse to show any picture at all.

Since you have low VHF and the towers are scattered all over the place you will need a really large combo Yagi style antenna and a rotator. At least that's where I'd start. The good news is there don't appear to be any large hills or mountains in the way. The bad news is you're looking at large antenna on a really tall tower, think ham radio style, to have decent success. Just depends on what you are looking to get.
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Old 28-Aug-2017, 7:49 PM   #3
JoeAZ
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Not really any decent signals from any direction.
If you absolutely feel compelled to try.....
I would start with the MCM Hi VHF antennas,
30-2475, aimed at D.C. Rf 7 and Rf 9. Get the
antenna as far away as possible from obstructions
(trees) in the direction you aim to receive. Use
good quality RG6 cable and keep it under 50 feet,
if possible. Good Luck.
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Old 28-Aug-2017, 8:23 PM   #4
jrgagne99
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MCM 30-2476 has more elements (gain) than the 30-2475.
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Old 28-Aug-2017, 11:21 PM   #5
JoeAZ
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Quote:
Originally Posted by jrgagne99 View Post
MCM 30-2476 has more elements (gain) than the 30-2475.
Yes! Yes! Needing all the gain possible to get those channels..
Do not forget to ground your system. It protects against lightning
and also can improve reception!
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Old 29-Aug-2017, 1:28 AM   #6
mikecandu
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I'd use an 8 bay like the DB8E or a CM-4228HD and point it towards the UHF CW station. I'd then point a VHF antenna like The Clearstream 5 towards the VHF stations at 347 degrees. I'd use the Channel Master Hi gain amp and feed it into a UHF/VHF combiner. I'd get a tower and put the antenna up as high as you can afford.

Another option is to put a big piece of metal in the air like the CM 5020 Masterpiece 100 on a rotor so you can rotate towards the station you want. Use a high gain amp.

After all that you'd still be lucky to get about 3 stations.
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Old 29-Aug-2017, 12:06 PM   #7
Jake V
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Your TV Fool Plot is resolved only to the block level. It's probably reasonably accurate, but maybe not. For better accuracy make another plot using the following directions and post it: http://forum.tvfool.com/showthread.php?t=14508

The antenna recommendations are all good.
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Old 29-Aug-2017, 1:44 PM   #8
BarberSurgeon16
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Thanks for all the help. I'll see if I can refine the location. I think the trees are the biggest issue. There are less trees toward the DC stations, and I Might schlep the HG back over and rig a reflector to see what happens.

Realistically is anyone getting reliable reception from stations in grey fields in the -5 to -10dbm range??? I guess that's the key question as to if it's worth moving forward.

Thanks!
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Old 29-Aug-2017, 2:13 PM   #9
jrgagne99
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Quote:
Originally Posted by BarberSurgeon16 View Post
Realistically is anyone getting reliable reception from stations in grey fields in the -5 to -10dbm range??? I guess that's the key question as to if it's worth moving forward.
With any 2-edge signal, it can be dicey, but it is still very possible even for NM = -5 to -10 dB, especially if you can find a hotspot where the diffraction patterns combine constructively. Hotspots can be only a few feet in X, Y, and Z, so it can take some effort to find them. They can also be frequency dependent, but hopefully you can find one spot that works for all channels of interest. The propagation model does not handle non-radial diffraction.

Last edited by jrgagne99; 31-Aug-2017 at 1:48 PM.
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Old 29-Aug-2017, 3:18 PM   #10
rabbit73
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Quote:
Originally Posted by jrgagne99 View Post
With any 2-edge signal, it can be dicey, but it is still very possible even for -5 to -10dBm, especially if you can find a hotspot where the diffraction patterns combine constructively. Hotspots can be only a few feet in X, Y, and Z, so it can take some effort to find them. They can also be frequency dependent, but hopefully you can find one spot that works for all channels of interest. The propagation model does not handle non-radial diffraction.
Excellent description of the problem, jr.
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Old 29-Aug-2017, 3:34 PM   #11
rabbit73
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Quote:
Originally Posted by BarberSurgeon16 View Post
.....I said I would bring over my basic Hoverman-Grey and my cheapy amp to see if we could get anything. Ran from existing roof mount, @25ft above ground.

No channels came up on search. Antenna pointed to try to pull in Fox and At least CW between 250* and 260*
I would have expected to get CW also. Maybe the trees are causing too much signal loss.

One of the problems with WUPV CW is that its transmitting antenna is very directional, and your friend's location is in a null where only 78 kW out of 1000 kW ERP are sent to that location:
http://www.tvfool.com/?option=com_wr...dALLTV%26n%3d1

WUPV will be moving from UHF channel 47 to VHF channel 8, which adds a complication:
http://www.rabbitears.info/market.ph...&callsign=wupv

What is the cheapy amp?

First try a test with a Solid Signal HDB91X UHF yagi and a good preamp might do better for CW. It that works, then try for ABC and CBS.

I agree with the MCM 30-2476 for ABC and CBS. Combine the two antennas with the Antennas Direct UHF/VHF combiner, AKA UVSJ:
https://www.antennasdirect.com/store...Combiners.html
avoid the MCM 33-2230 combiner; too much insertion loss.
Quote:
Location is at bottom of a hill, and there are trees.
Quote:
I'll see if I can refine the location. I think the trees are the biggest issue. There are less trees toward the DC stations
Would you be willing to send me the coordinates of the antenna location by PM so that I can look at the satellite view?
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Last edited by rabbit73; 29-Aug-2017 at 3:55 PM.
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Old 29-Aug-2017, 3:39 PM   #12
BarberSurgeon16
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http://www.tvfool.com/?option=com_wr...e6a43cc8cc102b

A touch better.
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Old 29-Aug-2017, 4:51 PM   #13
BarberSurgeon16
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Quote:
Originally Posted by rabbit73 View Post

WUPV will be moving from UHF channel 47 to VHF channel 8, which adds a complication:
http://www.rabbitears.info/market.ph...&callsign=wupv

What is the cheapy amp?

First try a test with a Solid Signal HDB91X UHF yagi and a good preamp might do better for CW. It that works, then try for ABC and CBS.

I agree with the MCM 30-2476 for ABC and CBS. Combine the two antennas with the Antennas Direct UHF/VHF combiner, AKA UVSJ:
https://www.antennasdirect.com/store...Combiners.html
avoid the MCM 33-2230 combiner; too much insertion loss.

Would you be willing to send me the coordinates of the antenna location by PM so that I can look at the satellite view?
That's a big shift for WUPV, probably not a great thing for my set up at home. Athough I have lots of signal from there, shifting lower in VHF will be harder for my HG. Looks like I may need to do some tinkering when that happens.

As for the amp, I don't know. It's from one of those flat black plastic indoor antennas that was given to me. The antenna had no VHF and in order to get NBC 12 I built the HG and ditched the little square guy. It's enough to help cut signal loss running from my attic to the basement and back to ground floor through some really old coax.
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Old 29-Aug-2017, 5:43 PM   #14
JoeAZ
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Quote:
Originally Posted by BarberSurgeon16 View Post

Realistically is anyone getting reliable reception from stations in grey fields in the -5 to -10dbm range??? I guess that's the key question as to if it's worth moving forward.

Thanks!
Yes!!! I install antennas in zip code 86314 and usually receive
KNAZ, NBC Flagstaff AZ, Rf 22, within the range you mentioned.
It takes patience to find the "sweet spot" where the signal is good
on the roof but well worth the effort!
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Old 30-Aug-2017, 8:27 PM   #15
rabbit73
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BarberSurgeon16

Thank you for the PM. I did a report based on the coordinates you gave me, and it matches your report in post #12 which is accurate for that location.

http://www.tvfool.com/?option=com_wr...e6a42c97d41a61

I see a house, back from the main road, surrounded by trees. The trees are visible and also some long shadows which appear to be from trees without their leaves; must have been after the leaves fell.

With your permission, I will post the satellite images for others to see. In the Google image the trees are bare and you can see the house. In the Bing image the leaves hide the house.
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Last edited by rabbit73; 31-Aug-2017 at 1:28 AM.
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Old 30-Aug-2017, 8:40 PM   #16
rabbit73
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Using the TVFool Interactive map, I tried different antenna heights. Please keep in mind that the computer simulation doesn't know about the trees and other ground clutter, it primarily uses elevation.









The Richmond channels get a lot better with the increased height, but 7 and 9 from the north stay about the same because they are blocked by the curvature of the earth.
Attached Images
File Type: jpg BarberSurgeon16TVF25ft.JPG (55.2 KB, 689 views)
File Type: jpg BarberSurgeon16TVF50ft.JPG (66.9 KB, 659 views)
File Type: jpg BarberSurgeon16TVF75.JPG (96.8 KB, 679 views)
File Type: jpg BarberSurgeon16TVF100.JPG (123.1 KB, 673 views)
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Last edited by rabbit73; 30-Aug-2017 at 8:44 PM.
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Old 31-Aug-2017, 1:24 AM   #17
rabbit73
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Here you can see why a little more antenna elevation helps with the signals from the west.



Here is the coverage for WUPV. Note that only 78 kW out of 1000 kW ERP gets to your antenna because of the directional transmitting antenna pattern:



Attached Images
File Type: jpg BarberSurgeon16TVFp2WUPV.JPG (104.0 KB, 693 views)
File Type: jpg BarberSurgeon16TVFcovWUPV.JPG (83.9 KB, 660 views)
File Type: jpg BarberSurgeon16TVFcovWUPVcu.JPG (84.6 KB, 664 views)
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Last edited by rabbit73; 31-Aug-2017 at 1:41 AM.
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Old 31-Aug-2017, 2:58 AM   #18
rabbit73
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The curvature of the earth blocks the WUSA signal. You can see why increasing the antenna height doesn't make much difference.



You can see you are on the extreme fringe of WUSA coverage:



Attached Images
File Type: jpg BarberSurgeon16TVFp2WUSA.JPG (108.0 KB, 674 views)
File Type: jpg BarberSurgeon16TVFcovWUSA.JPG (76.0 KB, 650 views)
File Type: jpg BarberSurgeon16TVFcovWUSAcu.JPG (122.6 KB, 662 views)
__________________
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Last edited by rabbit73; 31-Aug-2017 at 3:10 AM.
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Old 31-Aug-2017, 3:16 AM   #19
rabbit73
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I suggest you try the Solid Signal HDB91X and a good preamp for WUTV at 25 feet. The last time I checked, it was on sale.
http://www.solidsignal.com/pview.asp?p=hdb91x

Your G-H antenna doesn't have enough gain for WUTV.

It also doesn't have enough gain for VHF-High channel 12, even with NARODs, unless you built a VHF G-H like this:



For 7 and 9, try an MCM 30-2476 and a good preamp. VHF signals can get through trees better than UHF signals. It should get better after the leaves fall.
http://www.hdtvprimer.com/antennas/siting.html
scroll down to Trees and UHF

If you can go higher, then Richmond looks better. Maybe WWBT 12 with the 30-2476 and a good preamp.
Attached Images
File Type: jpg Flint_RidgeDHC GH6s.jpg (145.5 KB, 659 views)
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Last edited by rabbit73; 31-Aug-2017 at 3:44 AM.
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Old 31-Aug-2017, 3:53 AM   #20
rabbit73
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Quote:
Originally Posted by BarberSurgeon16 View Post
Realistically is anyone getting reliable reception from stations in grey fields in the -5 to -10dbm range??? I guess that's the key question as to if it's worth moving forward.
I think you must mean -5 to -10 dB Noise Margin (NM) range. Signals that are -5 to -10 dBm are extremely strong; strong enough to overload a tuner.

If an antenna is in the clear, it is possible to receive signals as weak as -15 dB NM. It is not possible to receive signals any weaker than NM -15 dB, because they are below the Thermal Noise Floor at -106 dBm. If you are able to receive signals weaker than -15 dB NM, either the TVFool report is wrong or the signals have been enhanced by Tropospheric Propagation.



Where the -106 dBm comes from:

http://www.aa6g.org/DTV/Noise/noise.html

I expect you to spend at least as much time testing as I have spent answering your questions.

Good luck

and

best regards,
rabbit
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Last edited by rabbit73; 31-Aug-2017 at 4:08 AM.
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