PDA

View Full Version : 2nd set of channels, 110 degrees off ?


squandry
28-Sep-2014, 7:36 PM
I have a roof ridge-mounted RCA ANT751 pointed south toward the cluster of towers of my local majors 25 miles away, and I do get decent reception for those; but I’m also particularly interested in ch43 and ch38 from a tower 15 miles east, at -108 deg. relative to the main. With my current setup I get no reception on those. It’s a challenging environment for those due to a ridge 1 mile east toward the tower that shadows me, plus I have 50’ tall high voltage transmission lines running north-south along the east edge of my property, maybe 60’ from the house.

So I’m soliciting opinions/options. Here’s my report: http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3dd2436e9a35a275.

More details on the current setup: To help pointing, I used a Winegard RFL-332 SensarPro to measure signal strength. I don’t know the units but the Winegard manual suggested a “40” is the threshold for reliable reception. Among the channels coming from the 187-189 direction, I maxed out at about a 55 when pointing at ~180 deg. true; was only about 45 when pointing at 188. Another interesting thing, rather than parallel to the horizon, I needed 5-10 deg. inclination to peak out the signal strength, maybe because those towers are up high on a foothill. (I’m on the Colorado front range.) So that’s how my ANT751 is mounted now, pointing at 180 deg. true and inclined ~5-10 deg.

Before it was mounted, the ANT751 was test-pointed at 80 deg., and the SensarPro showed marginal signal strength on CH43 of about 30, i.e. below Winegard’s recommended threshold. Certainly wasn’t a candidate for permanent pointing because signal strength for the majors was non existant that way.

As for the environment, this is a ranch house with neighboring 2-story houses to the immediate north and south. Tall mature trees throughout the neighborhood to the North, West and South. East is open except for the transmission lines and ridge. Wiring from Antenna is: 40’ RG6 from ANT751 to grounding block to 20’ RG6 to splitter, output#1 to HDHomeRun via 2’ RG6; output#2 to HDTV via: 2’ RG6 to coupler to 13’ RG6 to coupler to 3’ RG6. I didn’t use the SensarPro as an amp as I doubted it would weather well up on the roof, plus getting power to it wasn’t convenient.

So...maybe a 2nd antenna in the attic pointed at 80 deg., something big like a DB7e? I could power the SensarPro in the attic without a problem, and there is a convenient RG6 coax run already there, would just be a matter of a mounting. Not that I enjoy the prospect of assembling and mounting a large antenna in a fiberglass-filled attic, and a DB7e would be pricey for just 2 channels.

Or I’d be willing to consider a 2nd roof mount antenna if it’s on the small side, like a http://www.hdtvprimer.com/ANTENNAS/cm4221.html ? It seems to have a reasonable 12-14 dB net gain for these channels at least according to http://www.hdtvprimer.com/ANTENNAS/comparing.html, plus an advantageous null at +93 deg., to hopefully deal with a simple 2-way splitter/combiner, and avoid the need for a JoinTenna or TinLee selective multichannel combiner? But is this “old” unit the same as a currently available CM4221HD?

Or maybe I stay with a single antenna, and replace the ANT751 with something bigger like a DB7e with the panels pointed at different directions? But at least with that unit, then VHF CHs 7 and 9 might be a problem.

Enough of my rambling, I’ll shut up and listen now :)

GroundUrMast
3-Oct-2014, 7:09 PM
If your current system is providing reliable reception as is, it's hard to suggest you change it.

Given the 2-edge path and relatively low signal levels, a high performance UHF antenna such as the DB8E, mounted outdoors, clear of obstructions is certainly not overkill. A good preamp such as the RCA TVPRAMP1R would be needed aslo.

I'd rather cable the east facing antenna system separate of the existing system. This would avoid the expense of combining filters for each channel of interest. Instead, I'd use and external tuner to terminate the second antenna system. http://forum.tvfool.com/showthread.php?t=2882

squandry
3-Oct-2014, 9:53 PM
Thanks for the input. I'm not sure the benefit of receiving those channels would outweigh the aesthetic cost of a big outside antenna#2. Realistically cost needs to be more of a consideration too: between either the selective combiner or a second tuner (HDHomeRun in my HTPC application), an DB8E and TVPRAMI1R, plus cable and misc. mounting/grounding, I'd be up in the $300 which is probably $100 more than my comfort level given the benefit.

What odds would you give me with an attic install of the much cheaper and highly directional HD9032 (http://www.winegarddirect.com/viewitem.asp?p=HD-9032&d=Winegard-HD9032-UHF-Prostar-1000-TV-Antenna-(HD9032)&post=) (~$40, 16.3-15.7dB gain between CH32 and CH50), muxed into a cheap passive combiner (http://www.amazon.com/CHANNEL-2512-Passing-Splitter-Combiner/dp/B00006JPEA/ref=sr_1_1?s=electronics&ie=UTF8&qid=1412372884&sr=1-1&keywords=2-way+combiner+splitter)?

Another idea maybe more of a reach, but do people ever have success asking stations to change their transmission pattern? rabbitears (http://www.rabbitears.info/pattern.php?request=ant_pat&ant_id=85397&rotation=0&erp=1000) shows me they aren't shouting very loud toward my direction for some reason, despite the fact I live in a fairly populated area.

ADTech
4-Oct-2014, 12:02 AM
but do people ever have success asking stations to change their transmission pattern?

No. The FCC has almost everything frozen for the time being. Besides, there are usually reasons for such antenna patterns and transmit powers.


What odds would you give me ...

Flip a coin. Either it will work or it won't, it's impossible to say.

squandry
11-Oct-2014, 8:31 PM
Nope. Walking around the roof with the new antenna and a meter, there were a few places where I had marginal signal strength for 43 but I got nothing on 38 there. A few other places I saw a barely detectable amount on 38, but 43 was significantly worse there.

Bummer. Winegard HD-9032 for sale, anyone, anyone? :-/

squandry
14-Oct-2014, 4:10 PM
I'm still processing why this didn't work. Is the HD-9032 too directional for my needs, i.e. is the diffraction causing the inbound RF to come at me from various different angles such that most of it is missing the aperture of the antenna?

And a stacked reflector like the DB8E will effectively have a larger aperture allowing more of that energy to be captured?

On the HDHomeRun that is hooked up to my ANT751 pointed to the south, the other night I forced it to CH43 and CH38 and noticed it detecting some signal strength, ~50 out of 100 possible on both channels, but the symbol quality score was 0 except for some occasional brief instances when it seemed to shoot up before immediately coming back down.

squandry
11-Jun-2015, 2:59 PM
To record my final results on this, I was recently able to borrow a DB8e over a weekend, and when I first got it in an evening I quickly hooked it up directly to my TV and from inside my living room, pointed it in the rough general direction of the tower. Pointing it slightly down, I was able to get intermittent reception, which was enough to inspire me to try it on the roof during the next day with the SensarPro, but I was not able to find any consistent signal at any position on the roof. I guess between the 2-edge scattering and the power lines reflection, there just isn't enough energy making it to me despite only being 15 miles away. When we first moved to this house some years ago we did get reception from this station either from a preexisting attic Yagi that has since been removed or maybe even from a cheap Radio Shack indoor antenna...but no more for whatever reason.