Pixelation using an antenna & HDHR

[aeblank]

So I have media center 7 with a pair of HD Homeruns.
I have a very strong VHF station a few miles to the south and the remainder of my stations are weaker and to the north-northeast (I'm in Cadillac, MI and the stations are in Kalkaska, MI).

So, I get brief moments of pixelation. Normally in the evening and it is only on those "weaker" stations from Kalkaska.
I have a "Yagi" style antenna, perhaps like this one (http://www.radioshack.com/product/index ... Id=3739596).
I also have a no-name (that I can find) amp that I have no recollection of buying, but I obviously did.

So I'm trying to solve this issue. I bought a channelmaster 7777 and a Winegard HD7694P. It is WORSE. It was good when i put it up, mid-day. That evening it was awful and this morning I can't even get my strongest channel, which my fillings should pick up (one of, if not the, strongest station in the state).

So, what should I do? the strong channel is VHF (yeah), and the others are UHF. Feel as though my highly directional antenna is probably good, as it weakens that very strong station (which is good), since it is pointed in the opposite direction.

So should I get a higher gain yagi style, or a massive uhf/vhf antenna?

UHF/VHF:
http://tinyurl.com/kxc7cy8 My problem is UHF, and I think only a small portion of the antenna is UHF.

Higher (?) gain UHF
(urls in next post, reached my URL limit)

I guess I'm hoping for someone with a strong theoretical knowledge of antennas/signal.
Another option is to get an adapter to go from the 2-wire output of my current antenna to the coaxial input of the new amplifier.

Also wondering if I'm chasing something that can't be fixed.

Please help!

[aeblank]

http://tinyurl.com/mavx9h3
http://tinyurl.com/m7e5v94
http://tinyurl.com/m3o5bsv

[barnabas1969]

I recommend that you go to www.tvfool.com, and click the "TV signal locator" link on the left side. Their site appears to be down right now. When it comes back up, go use their signal locator. It will tell you lots of info about your stations, including compass direction and type/size of antenna you need in order to receive that station.

Another good resource (but not as detailed) is www.antennaweb.org. They have a color code to tell you what size antenna to buy. Many antennas have this same pie chart of colors on the box.

What model HDHR do you have? Do you have an older model HDHR that has two coax inputs on each unit?

Based on your description of the direction where the transmitters are from your location, my recommendation would be to buy two antennas. One VHF and one UHF. Make sure to get the right size antenna for the stations you want to receive. Point the VHF to the south, and point the UHF to the north/northeast. You can mount them on the same mast... just make sure to separate them by about 18 inches. Mount the VHF lower than the UHF.

Run a coax from the VHF antenna to the input of one of your HDHR's (hopefully one with two separate inputs so you can dedicate a single tuner to your VHF station). Run a coax from the UHF antenna to your other HDHR (hopefully to three of the other tuners, if you have at least one older model HDHR with two separate inputs). Setup Media Center's "Edit Sources" page so that the VHF channel ONLY uses the tuner which is connected to the VHF antenna. Setup the other channels to ONLY use the tuners which are connected to the UHF antenna.

But... before you make any decisions... go to those websites I listed above and determine exactly where the transmitters are located. If you were wrong about the VHF station being in an opposite direction of the UHF stations... then my advice above would be incorrect.

[barnabas1969]

Oh... another really cool feature on tvfool.com is the ability to map the transmitters on a satellite image. Then, you can zoom in to your house, and pick the spot where your antenna is located. A line will be drawn to that spot from every transmitter. Then, you can zoom out a little to find a reference point in your neighborhood (a tree, the neighbor's chimney, whatever) to aim your antenna at. In my setup, I found that aiming the antenna at the front-right corner of the neighbor's house across the street was the sweet spot right in the middle of all the transmitters.

[barnabas1969]

Another great resource is if you have a local electronics hobby shop (NOT Radio Shack!). You may be able to go there and get great recommendations for antennas. In my area, there's a little shop named TedCo. It's run by an old man named Ted. He's been in business since the early 60's. I walked in and asked for his recommendation. He had the exact antenna which was tuned for the channels in our area in-stock... and he sold it to me cheaper than I could have gotten it on Amazon or e-Bay. He even sold me the mast cheaper than I could find it anywhere else.

[aeblank]

I have the new, single-input HDHRs (two of them).
I've been to tv fool, and antennaweb (though it's been a while for that one).
I wish there was a place like that around. I've talked up places over the last few years, and nobody knows anything, relatively speaking.
I'm an engineer by trade, and while I'm no genius, I think I understand RF better than anyone around. Everybody has cable or dish or isn't trying to get the "hard to get" stations. Bleah!

I feel as though I need to be careful of over-driving my strong station, so the directional type (pointed the wrong way) seems good and works fine in my "old" setup.
My signal is 100% for 99% of the time, but dips to 40% (or similarly bad) randomly. I'd like to understand what the HECK is causing that, and if it is a fixable item.

[barnabas1969]

It could be many things causing the problem... the weather, solar radiation, some other nearby interference... whatever. Sometimes, simply moving your antenna up or down can fix a problem like that. TV Fool has a tool on their site that approximates the signal on a vertical axis... attempting to take buildings, hills, trees, etc into account. It's interesting to look at. You might find that your antenna is just in a bad spot for reflections or whatever.

[barnabas1969]

Oh... and reflections are exactly why you should not point a directional antenna the wrong way in an attempt to attenuate the signal. That's what attenuators are for. They're cheap and can be installed in-line with the VHF antenna.

[aeblank]

Attenuator makes sense. I agree with the comment, in general. To be clear though, I'm specifically pointing my UHF toward the station and just happening to get the strong VHF "on the back side". Unless reflections from the strong station are randomly screwing up my other stations, I'm not concerned with it for right now.

[barnabas1969]

Yeah, I saw that it's a UHF antenna. Anything will receive a very strong signal, even the wrong type of antenna. It would be a shame to waste both tuners in one of your HDHR's (unless you can buy one of the older models on e-bay or something). But you could even try connecting an indoor VHF antenna to one of the HDHR's. Just a simple pair of rabbit ears should do the trick if the signal is as strong as you say it is. You could even calculate the wavelength of the center frequency for that channel and adjust the length of a pair of rabbit ears to be 1/4 or 1/2 the length of the wave.

I assume you're talking about WWTV channel 9 (both virtual and actual 9). If so, the center frequency would be 186.31MHz. That gives you a wavelength of 63.39 inches. Half wave would be roughly 31.7". You could easily adjust a pair of rabbit ears to 31.7".

Antennaweb says you need a medium sized multi-directional for that station.

[aeblank]

Yes, I get 9 no problem.
I'm confident I could get it with a pair of rabbit ears on one of my HDHRs.
However, why?

The problem I'm having is on the weaker stations (PBS, NBC/ABC). 29.x and 27.x out of Kalkaska (35 miles using antenna web).
Actually found my house and put the flag right on my tripod. I'm 95% sure I'm pointed in *exactly* the right direction.
Assuming the roof isn't a slick mess (snowing here today), I'm going to take down the new antenna and move my existing one up 2 or 3 feet.
See what happens.

I shotgunned a larger uhf yagi to try too. 70 mile range (16dbi gain?). I guess I'm in the experimentation mode.
Thank you Amazon for your fast shipping and free returns.

[dmagerl]

Before going to all that trouble of taking down and returning the antenna, Check your sources in the guide. WWTV is one of those stations with a repeater (it's listed twice in tvfool) and MCE doesnt handle those very well.

Go into Edit Channel/Edit Sources and see if you have more than one source per tuner and then disable the ones you cant receive.

[barnabas1969]

@dmagerl: Good advice!

[barnabas1969]

Yes, I get 9 no problem.
I'm confident I could get it with a pair of rabbit ears on one of my HDHRs.
However, why?

I thought you were saying that channel 9 was the problem. OK... so you need to make sure that your antenna is aimed correctly... and that you have an antenna with high enough gain. Also, make sure the amplifier isn't a cheapie low-quality one. And, make sure all your connections are tight. The higher frequencies will show the effect of bad connections and poor quality components before the lower frequencies will.

[barnabas1969]

I missed the part where you mentioned using the new amp with the old antenna. That might work. You should have no problems finding an impedance matching transformer (the 2-wire to coax adapter you were talking about) at Radio Shack, Home Depot, Lowes, e-bay, or Amazon.

[aeblank]

So, interesting results..

<rant>
So, I had the plan. Pick up the wife's car from the tire shop, quick stop at home depot for paint samples and 300 to 75 ohm converter, then home and on the roof before everyone else gets home and before the snow (yes, snow) makes the roof slippery. So I got the car, found the packages I had to go to UPS for, then went to ups. Then home depot and the lady took probably 20 minutes or more to mix my two paint samples. Then the losers don't have ANY reasonable TV stuff. They only sell overpriced HDMI cables now. So I go to Radio Shack <shudder>. 3 people in there, only one knows where stuff is. They don't have the kind I wanted:

But they had this kind:


So then I get home after making sure Walmart doesn't have the right adapter AND getting gas. Don't forget, 29F and snowy out.
Finally get home, 5 minutes before wife and son. I have to find a scrap of wire to go from the adapter to the antenna. Also need to find a coupler to go from the adapter to the coax to go to the amp. In my low-voltage work bucket, I find that i HAD an adapter like the overpriced one Radio Shack sold me. Grrr.
</rant>

So, I eventually hooked up the old antenna (that was already pointed perfectly, according to antennaweb) to the new amp. It was *almost* perfect. Wife watched most of Dancing (on my weak ABC station) and it was perfect except for a couple minutes about an hour in. So I guess it gives me hope. Worst case, I'm better than I was. I think I'm still going to try the stronger Yagi that I bought (http://tinyurl.com/kw9vyhe) and see what happens. I will have to wait for the snow to melt/dry though. 6/12 pitch doesn't go well with 2" of snow.

All my connections are/were tight. Antennaweb was cool because I was able to put the push pin directly on my tripod with the satellite images. I don't have any notable landmarks to point to except the corner of my fireplace chimney, 40' away. Worked very nicely. The amp is a channelmaster 7777. As far as I know, that's about as good as it gets. I haven't sealed up all my connections yet since I'm still fooling around. I think I'll get some self-vulcanizing tape and use that, when the time comes. Signal was so close to perfect last night, and it was stormy/blowy too. I'm not 100% sure that I'm not overloading my network card either. I had 4 tuners going and at least one xbox, all on a 100M switch. Been pondering a couple network cards and hooking the HDHRs up direct--but then I lose the ability to check the signal on my phone.

Anyway, thanks. We'll see where I end up.

[Mike88]

So, interesting results..

FWIW I watched some of DWTS with my wife last night, but time shifted using the satellite DVR which also has an OTA tuner. IOW it was an OTA recording. I don't recall at what point in time, but the picture went black, however only for a few seconds in my case. In could have been the DVR or the ABC signal. Thought I'd mention this because perhaps there was a glitch in the ABC signal & your antenna system is OK.

[barnabas1969]

A 100Mbps network should handle 4 tuners just fine, unless you're also running some extenders from the HTPC (or transferring files to/from another computer on the LAN).

Instead of taping the connections, go get some silicone lube at the local pool supply place (it's a silicone gel for lubricating the O-rings on the pool pump - it never dries). It comes in a small tube similar to a tube of toothpaste. The ones I buy are called "Lube Tube". Fill the connectors with that before you screw them together. Water can't get in when the connection is full of silicone.

I just Googled "Lube Tube" and I got a bunch of porn links. Here's a link to one being sold on e-bay for $8.99, which is a ridiculous price. I think I pay like 4 bucks for a tube at my local pool supply place.
http://www.ebay.com/itm/LUBE-TUBE-TEFLO ... 0702090282

[barnabas1969]

I missed the part where you said, "...and at least one xbox..." OK, so if you have four tuners in use and you're also driving 2 XBox extenders, then you're at the limit of what you can push over 100Mbps. If something else (like Windows Update) transfers data to/from the PC while this is happening, you could have some problems. You should upgrade to a gigabit network, that way you can still check the tuners on your phone.

[barnabas1969]

One other thing... you definitely need to replace that 300-75ohm transformer with the other type. The type you used is probably OK for a short-term solution, but most of them are not designed to be outside in the weather. It also adds an extra connection (the coupler) and can't be tightened like a normal F-connector. You should order one on e-bay or Amazon:

This one is $2.42 plus $2.41 shipping:
http://www.ebay.com/itm/Steren-200-490- ... 4d17d3e7e1

This one is $4.88 with free Prime shipping (if you're an Amazon Prime member):
http://www.amazon.com/Steren-Outdoor-30 ... er+outdoor