The Official AVS Antenna and Related Hardware Topic! - Page 394

I make up masts from here: http://www.dxengineering.com/Product...=136&DeptID=43
John

How do you join the lengths of 6 feet? The only thing I am familiar with would be a band exhaust clamp made for butt connections. Something like a 2" one of these or a 1" one of these. I'd need something between these sizes probably.

EDIT: Nevermind. You stack different diameters on each other, with the bottom obviously being the largest, and use their clamps. They look like regular hose clamps but I assume they are designed to hold the shaft from spinning in bad weather.

Do you think 1.5" for the bottom 6 feet and 1-3/8 for the top 6 feet is enough to hold up an 11 foot antenna like my Winegard 7697P?

Additional ways to NOT receive OTA signals:
http://www.tvtechnology.com/article/88182

1) Indoor Passive Antennas were found to have Gains ranging from -6 dBd down to -15 dBd....or worse.
[MUCH WORSE THAN WHAT MOST ANTENNA MEASUREMENTS INDICATE.....]
[Perhaps they were referring to UHF-only antennas??? And if they were, why not say so???]

2) Indoor Amplified Antennas were NOT improving the situation and usually made it WORSE,
including amplified FM signals overloading the DTV.
[VERY UNEXPECTED AND CONTRARY TO MY EXPERIENCES.]
BTW: Second harmonics of FM stations interfere with Hi-VHF Ch7-13....not UHF.

3) People were "hiding" the antenna behind the TV or AV-Gear stack.
[DUH!!!! GUARANTEED TO KILL WHAT LITTLE SIGNAL THERE MIGHT BE....]

4) Interference from the AV-Gear, fluorescent lights, cordless phone base stations, et.al.
was frequently a problem....Part 15 rules should be reviewed.
[Q: WHERE'S THAT IN THE SETUP INSTRUCTIONS??? A: Just after the lightning warning???]
[BTW: Yet another reason why TV-BAND DEVICES (WSD) will be a problem....]

5) Location, Location, Location....moving the antenna HIGHER was generally better.
[BUT WATCH OUT IN APTs/CONDOs BECAUSE YOUR "ROOF" MAY CONTAIN METAL REBAR.]

6) Leakage of Cable TV signals were sometimes interfering with OTA reception.
[COULD BE DIFFICULT TO TROUBLESHOOT.]

7) People were confused by the ill-conceived "virtual channel" confusion and were NOT
aware that the REAL channel might be in a different band and require a different antenna.
[DUH....ANTENNA DISCUSSIONS WERE MISSING IN THE PSAs!!!!]

I bought army surplus heavy duty interlocking fiberglass poles, paid 1.00 per 4ft section, up 20ft and works great and dont move a bit.

Home Depot has 10' lengths of electrical conduit in 1 1/2" and 1 1/4" dia. Also, RadioShack sells 10' and 5' 1 1/4" masts. Home Depot is cheaper, but not as pretty.

oz

Yep, and a lot of commercial antenna masts sold are thinner, weaker, and pricier than common electrical conduit or chain link fencing tubing.

Try laying a couple of 32" long aluminum tubes/bars, centered and connected to, the old reflectors and see if it does the trick.

Someone earlier on this forum mentioned noise from lawnmowers. Today, a neighbor down the street with a motorcycle went by and I noticed pixelation on RF channel 17. Signal strength at the time was 95%. When he came back by, the same pixelation occurred. I never noticed any interference from gas motors on UHF with analog.

There is a post on today's Atlanta avs saying that a UHF antenna that receives vhf signals is not good, becasue of vhf noise. I receive three vhf stations on my mc4228, one of those ch 13 with an occasional audio drop even though the signal is in the 90s.
I'm thinking it just the nature of digital on vhf, and not the uhf antenna.
Some thoughts please....

It must have been an older carburated non-computer controlled engine. And he's probably running spark plugs without resistors or very low resistance plug wires. That causes a boat load of EMI and in cars this problem was looked into and solved pretty much the first time someone wanted to listen to the radio while driving.

Either it's a coincidence or my aim plus all the limbing and removal of trees has actually improved my reception. I haven't had any cut outs on the off axis stations, CW and ION. I have a couple larger higher limbs to remove when I raise the antenna but I am now optimistic, especially given the properties of UHF.

No coincidence. Last year, I cut off a large basswood/lime tree limb that was in my path, and the channel that was on at the time went from snowy to crystal clear as the branch hit the ground.

Yeah, Im sure of that, heh. But with analog uhf, it was never noticible.

Based on the current aim the only thing directly in the path were some white pine limbs. Not exactly a big leafy oak or something. And I don't know why that would help stations that are completely off axis from this aim. But I'll take it for sure. I would recheck the signal strength on my channels and maybe try a few of the "dead" ones but House is recording and I still have only 1 tuner. I gotta build that multi-tuner HTPC. Come on Win 7 release...

Just a random comment on this whole project. While I was on my roof I guess a neighbor spotted me and later chatted me up about what I was working on. In general I've found people are very aware about ATSC though less aware of the quality of the HD content when it is being broadcast. And I have yet to run into a single person that is doing what I am doing, not even including the Media Center DVR setup. I guess people gave up on broadcast by the 80s and early 90s and never cared to look back. But they didn't have Hulu and Netflix then, either.

I think transition to DTV is creating renewed interest in over the air reception for two reasons. Cheap folks like me would rather spend a few hundred dollars every couple of decades for an antenna rather the $50-100 a month for cable or Sat. At the other end we have audio and videophiles that cherish OTA picture quality because it is not transcoeded to squeeze a few more channels onto Cable or Sat.

As long as that station doens't have any subschannels you may be right. Now take a station like WTVF which is 1080i and it has not one but TWO subchannels. Well something has got to give.

Not to mention, I also heard a theory that the networks may actually broadcast a more compressed version of the content, if only because their major customers are cable companies that have to compress it anyway. So you might be getting some inferior bitrate like 6Mbit encoded into the 19Mbit for broadcast. There would be no way to tell other than quality loss.

In general, sounds like mis-information....many users of Combo VHF/UHF Antennas say otherwise.
Since Preamps and Tuners have separate VHF and UHF sections, the third harmonic
products of VHF signals do not interfere with UHF.

Perhaps it was a comment made wrt to combining a Combo VHF/UHF Antenna with
another VHF Antenna???? This could degrade VHF performance since the noise and
interference would be the total from BOTH antennas. Which is why the JoinTenna
was invented.....and UVSJ Diplexer Combiners are used to merge VHF & UHF Antennas....

It's the antenna.

The 4228 has a poor front to back ratio on VHF. This means that noise and reflections off the back are picked up all most as easily as the "main" beam.

An antenna designed for VHF has a high F/B ratio which reduces noise and reflections.

The source of the information is http://www.avsforum.com/avs-vb/showt...1#post17306079

Channel 13 has a F/B ratio of just over 10 db. Channel 7 is 0 db. The best channel is 10 at 15 db F/B.

The idea that a 4228 is a good VHF antenna originated in Connecticut. WTNH-DT in New Haven is on channel 10. Unfortunately, you should not translate that success to other VHF channels.

You could always use galvanized water pipe.

Watch out for the gauge of the steel in the mast. The cheap one from Summit Source is 20 gauge. In my opinion that's too weak for your HD7697P.

This mast is galvanized steel and 16 gauge.

http://www.channelmasterstore.com/TV..._p/cm-1610.htm

At first it looks expensive, but they don't charge extra for shipping.

Actually the opposite is true. Higher frequencies penetrate less.

I agree. I did not have much success with the bow tie antenna except when it is a single bow. The 4 bay had ghost on some of the channels when the analog was on the air that were not on the vhf uhf combo. I would get a vhf high band to receive the vhf channels. But if you do that & still use the uhf bow tie antenna you may need a uhf/vhf antenna joiner that includes filters. It would block any vhf signals from the uhf bow tie antenna. If they are not blocked they would interfere with the good signal from the vhf high band antenna. you would need to check the spec on the joiner to make sure it does block the signal that you do not want from the antenna on each port. I have a joiner & it does work.

Home Depot has some 16 gauge options as well in terms of the fencing. I didn't see any 12' sections online, but I think you may find a one piece solution there at a reasonable price.

1" Black "iron" pipe:

http://www.homedepot.com/Building-Ma...atalogId=10053

1" pipe is really 1.315" OD. The stock item at Home Depot is not galvanized. The wall thickness is substantial. The yield strength of "Black iron pipe" is not rated, but you can assume it to be in the 30,000 PSI to 35,000 PSI range. A steel mast should be rated at 40,000 PSI.

Wall thicknessess

16 gauge .0625
20 gauge .0375
schedule 40 pipe .133

The schedule 40 pipe will beat the strength of 16 gauge antenna mast by a factor of about 2:1 and 20 gauge by about 4:1.

If there is a plumbing supply store in your area call and ask for 1" schedule 40 galvanized pipe (unthreaded). Every TV U-bolt that I've seen will fit on 1.315" OD.

I was talking about the aluminum masts linked by someone else but this also looks good. Thanks.

The aluminum ones are here. .058" wall 6063 aluminum. I was talking about stacking a 6' section of 1-3/8" OD on top of a 6' section of 1.5" OD, of this material. I think I'd rather do a 1 piece, though. Then again, a joint in the middle would likely make it easier to re-aim, as I could simply loosen the clamp and twist. Plus it's aluminum so it should be less likely to corrode and freeze in place.

.058 wall is too thin. Try this instead.

http://www.onlinemetals.com/merchant...d=73&top_cat=0

I'm new to the forum, so forgive me if I'm covering something simple. I've searched through the forum, but didn't find quite my particular situation.

I have a very specific objective, to improve reception of Channel 2 (digital channel 25) from Pittsburgh. I'm located about 65 miles NW of the KDKA antenna.

I am fortunate to have a third story roof onto which I've mounted a 12' mast, getting me pretty high with no nearby obstructions. I mounted a DB8 UHF antenna connected to a CM7777 Pre-Amplifier. The output is split to the TV and to a Satellite DVR that integrates OTA signals. (I've have removed the split with little impact on reception).

The result has been pretty good. The satellite receiver indicates signal strength with a rating of 0 to 100. With this setup, channel 2 registers in the 60s, but the signal strength varies significantly. It will bounce around between 55 and 70 with some pixelation, but occasionally, it will just drop to 0.

My questions:
Is this normal behavior for a distant source? Does 0 just mean that the signal has dropped below some minimum for the tuner and so it reads 0, or is the signal actually going away completely?

Secondly, any suggestions for further improving reception strength or stability? I've read in these forums the difficulty of combining antennas pointed in different directions, but what about for pointing them in the same direction? I have room on the mast to add another antenna if that would help. If so what are your suggestions for antennas and setup?

Thanks, Dan

Start at tvfool.com. It will show you what signal strength to expect. Here's the report for Warren, OH.

http://www.tvfool.com/?option=com_wr...befbff101160bc

If Warren is close to your actual location, your 7777 preamp is overloaded.

This is what is involved with stacking identical UHF antennas:

http://www.hdtvprimer.com/ANTENNAS/16bay.html

As proved by Buckaroo Banzai at the Banzai institute and latter stolen by John Smallberries at yoyodyne.
P.S. You will never get the Oscillation Overthruster

Actually you're wrong.