[mrisch]

So, I got the Channel master directional UHF antenna, but I think the hills of San Carlos (Bay Area) are just to much in the way. The best signal I got was 30 in any direction.


Will a pre-amplifier help? What kind should I get?


Thanks for any help.


------------------

Regards,
Michael Risch

 

[john stephens]

mrisch,


Post a long/lat and I'll try to help.


Regards,


John Stephens

 

[mrisch]

Thanks.

37.496859 N, 122.267356 W (for the 94070 zip code, don't know how to get it for the address)


I have a DTC100. I get a 60 signal strength with KQED 60, 47 with KRON 4 and WB 20, 27-30 with UPN 45 (not really acceptable) and KPIX (which has the most HDTV) is nowhere to be found.



Thanks,

Michael Risch


------------------

Regards,
Michael Risch

 

[john stephens]

Mike,

The centroid of the zipcode may be far enough away that the answers I provide are unreliable. It appears that you think a set of hills are blocking you. These are not necessarily blocking the view from the zip centroid.

Therefore, browse to:

http://www.mapblast.com


Get map for your address and the long/lat will be at the top.


Regards,


John Stephens

 

[dmaneyapanda]

John,


After weeks of fruitless searches, 2 different receivers, and 5 antennas, I could use any help I can get, too.


I'm in NJ, roughly halfway between NY and philly. my lat/long, as reported my mapblast, are:


Lat: 40.316008 Lon: -74.663777


thanks in advance!


dinesh



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DVI/HDCP sucks. DFAST sucks. Boycott JVC.

 

[john stephens]

dmaneyapanda,


There are no natural obstacles blocking you from receivng stations in Philly or Neew York. There must be some special circumstances that you haven't mentioned, which have caused your problem. In any case, you are 46.5 miles from ESB and 43.7 miles from WTC in NYC. And 37 miles from WCAU in Philadelphia. These are essentially 180 degrees apart, bearing ~50 degrees to the NYC stations and 238 degrees to WCAU in Philadelphia. Other than the usual ensemble of urban reflections off tall bldgs, there don't appear to be any special challenges to reception.

You need a high gain antenna mounted outside and high up. Need to outfit it with a rotor if you wish to do both cities. Use a CM 4248, together witha CM7775 preamp up close, use a rotor point accordilingly. Bearings are relative to true north, not magnetic. Good luck


Regards,


John Stephens

 

[J.P.Heff]

Hi everyone, new to this forum and yes I am experiencing antenna problems also;

John Stephens thanks so much for your most valuable advise, any suggestions

Location: Eaton Rapids, Mi 48827 Zip Log/Lat 84.656545---42.516624

Address: 8374 E. Clinton TRail. Log/Lat---84:40:26.447W---42:31:7.230N

Decimal Degrees -084.674013 Lat.42.518675

Currently trying to acquire two DTV stations;

WLNS-DT Lansing, Mi. Transmitter 42 degrees 41' 19" N 84 degrees 22' 35" W

Distance 18.49 Mi. 600'(soon to be 900') @100,000kw Channel 59-1


WOODTV Grand Rapids Transmitter 42 degrees 41' 14" N 85 degrees 30' 34" W

Distance 44.95 Mi. 715' @168kw Channel 7-1

I installed DTC-100 about six weeks ago. My antenna is about nine years

old with new RG-6 last year,solid copper double shielded#E108998-T

I believe antenna is Winegard, but no markings. Its VHF/UHF blue and silver

with 21 VHF elements and 24 UHF elements, approx. 120"-130" in length.

The pre-amp(my biggest concern) is mounted on the bottom of antenna

at the end of V of the UHF elements. Clear bo no markings it to is about

nine years old. If memory serves right the installer put in the most powerful pre-amp. Power supply is wine gard mounted in my A/V cabinet.

Antenna has always been able to pull more distant stations 40-70 Mi.

but I have three that are from 5-10 Mi (all analog) that are problematic with ghosting and double images Channel 6 is one of these which is also the

same tower for DTV 59-1 CBS.

When I first installed my RCA unit I was able to get NBC's 7-1 station

for about 10 days but have not been able since. I could never even

get banner for 59-1 CBS. However I can get analog. I put in a Terk TV25

on the second antenna input and have been getting CBS 59-1 with that

at about 76-82 signal strength when the rum full power after 5:00 PM

I still cannot get NBC 7-1. Also in two strong wind storms I would

lose signal.

We have a older home and antenna is mounted on peak of first story.

There is a large Maple tree on east side of house that is in line of sight of 59-1. but for the most part we are elevated over existing rural homes

with 500' or better to closest neighbor.

I have a antenna installer coming over this Thurs. as I've explained this problem to him. He helped with a dish and new coax about a year ago but did not do the antenna install. He thinks the pre-amp is to strong and suggested we try a Winegard AP8700 as he is a winegard dealer.

Can I get both channels with one antenna, or do you think I need to install separate UHF. But I still need to be able to get 7-1 (VHF).

Any suggestions would be most greatly appreciated, and thanks to everyone on this Forum for all the valuable information and advise.

John





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JPH

 

[john stephens]

Does sound like overload. Try this first. Insert a variable attenuator in the output of the preamp and see if you can find a level where everything works. Failing this, I'd recommend two separate antennas, the existing one for distant stations, a CM GS1000 or 2000 for the nearby stations.


Regards,


John Stephens

 

[J.P.Heff]

John Stephens, thanks for the reply:

A couple of questions;

You suggested inserting variable attenuator in the output of preamp so I

take it these are for outdoor use. Are the variable type avaliable? If

not what size might you suggest? RS always refers to preamps as amplfiers

but they are the pereamp with power supply located indoors, correct.

Also would it be possible to mount CM GS2000 on the top of the same mast as

current antenna and bring in another coax, that way I could utilize one

antenna and rotor. a new IR control for rotor is starting to look very good,

any thoughts?

Thanks again

John





------------------

JPH

 

[john stephens]

J. P.,


No, they don't need to be out door. You can insert it in the line near the STB where you can get easy access. In fact you can add a small length of additional cable so you can view the TV while you adjust the attenuator. OK to buy a RS variable attenuator, perhaps 0 to 10 dB. But do not buy a radio shack preamp, get a Winegard or Channel master low noise preamp. CM7775 is excellent, best noise figure, high gain.


Regards,


John Stephens

 

[john stephens]

Mike,


There are lots of hills around your home Kinda like threading a needle. One possibly troublesome little hill about .25 miles from you along the route to Sutro. Lots of others, too, but they are farther away and of no concern. This nearby hill is 300 feet, but you property is at 193, so about 100 feet rise, perhaps a bit less. In any case, let's be optimistic, here. You say you are receiving KQED with a 60 strength, hopefully this is with the 4248 pointing in the direction 331 degrees true. Is that with your antenna pointing towards Sutro? Also, how long is your cable run from antenna to STB? What kind of cable? I wonder also, what kind of reception are you getting on analogue channel 44? Any ghosts? Trying to get a feeling for whether you are threading the needle on this nearby hill or whether you are receiving a reflected signal. All for now.


Regards,


John Stephens

 

[mrisch]

John - you are all over it. Here is more data:


UPN 44 is visible, but ghosted pretty badly

36 is super duper clear in both analog and digital

I am pointing just about parallel to the direction of San Carlos Ave., which antennaweb.org says is the direction of Sutro Tower. It is a NNW direction, which is about 330, I suppose. Take a look at "san carlos & beverly" on maps.yahoo.com to get a picture of the road's direction. It is pointing at the pine tree in the neighbor's yard- just my luck. Does that have an effect?


------------------

Regards,
Michael Risch

 

[ClaudeD]

John,


Since I'm only 18 miles from NYC, I've been assuming that I have a multipath problem. Could you verify for me? Latitude 40.7427, longitude 74.3317 (i.e., zip code 07078). I'm pretty high up a hill, but perhaps not high enough to get straight line of sight to NYC.


I'm using a ChannelMaster UHF antenna (forget model #) with a rotor and pre-amp. I've tried an attenuator, but it didn't help.


Any help very much appreciated. My DTC100 gets CBS about half of the time; I'm considering getting a Princeton Graphics HDT-2000 for its purported ability to deal with multipath.


TIA,

Claude

 

[mrisch]

John, looks like you opened a can of worms! Thanks for your help.

OK, here is the mapblast info for my address


Lat: 37.502636 Lon: -122.278623


------------------

Regards,
Michael Risch

 

[Bill]

Hey guys,


I use a "Radio Shack" variable amp (UHF KHZ range) just before it goes into the TV. Give it a try, you can always return it.


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[john stephens]

Mike,


Ok, the fact that you are seeing those ghosts on 44 analogue, means that those hills are doing a little multipath job on the signals from Sutro. The fact that you are receiving a 60 signal on ch 30 is great testimony to the ability of the digital filters in the STB to function in the presence of multipath. 60 is a marginal signal, though, and there is a need to increase your signal to noise ratio at the STB. As you are currently configured, with no pre amplification, you are degrading the input S/N at the antenna by 12 dB due to the 10 dB NF of the STB and the 2 dB loss in the cable. This is leaving you in and around the threshold for the lower frequency channels and well below for the higher frequency.

We can improve things considerably by using a good preamp. A CM7775, with it's noise figure of 2, will increase your S/N by 10 dB, placing you well above threshold.So get that and mount it close to the antenna.

BTW, as an aside, if you want to play with tweaking the antenna pointing, you want to error only in the eastward direction, slightly, not westward. Take a compass and measure the bearing, taking care to remember that the compass will measure 15 degrees too low(here in CA). Should point towards 317 degrees, not less. You don't need to do this if you install the preamp. All for now.


Regards,


John Stephens


[This message has been edited by john stephens (edited 03-12-2001).]

 

[john stephens]

ClaudeD,


Unfortunately, there is a very broad ridge 0.9 miles east of you that blocks your line of sight to the transmitters. The rise is about 110 feet over the .9 mile distance. It so thoroughly blocks your line of sight that it's hard to see how reflected signals could get around these two ridges. All for now.


Regards,


John Stephens

 

[mrisch]

To answer the other questions - it is about a 25 foot run - top of the house down to the TV and RG6 cable.


------------------

Regards,
Michael Risch

 

[mrisch]

Thanks John. I will test it out and report back.


------------------

Regards,
Michael Risch

 

[ClaudeD]

John,


Thanks so much for your information, even though it was bad news. You really are going above and beyond the call of duty for a forum member.


Claude