The Official AVS Antenna and Related Hardware Topic! - Page 397 - AVS Forum
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post #11881 of 16297 Old 10-11-2009, 02:39 PM
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well, the coat hanger didn't work. I am puzzled by the signal strenght, today at 90 one minute and gone the next. The reason I think they may have problems GPB TV's main transmitter is on ch 8 in Stone Mt. Ga, which I received very well until they activated their lp transmitter here in Toccoa, it too is on ch 8. When the local signal went dead
I was able to pick the Stone Mt. signal again on my "Atlanta" antennas
(ya1713).

Would the loop tubing be like "ice maker" tubing?

I have sent an email to one of their engineers.... maybe it is them....

Tired
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post #11882 of 16297 Old 10-11-2009, 03:41 PM
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Quote:


Would the loop tubing be like "ice maker" tubing?

Yeah. Use whatever is cheapest, but you do want it to hold its shape.
Follow holl_ands analysis here:
http://www.imageevent.com/holl_ands/loops
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post #11883 of 16297 Old 10-11-2009, 04:42 PM
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Thanks 300, Printed the info and will give it a try tomorrow...

Tired
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post #11884 of 16297 Old 10-11-2009, 06:46 PM
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Quote:
Originally Posted by kovax View Post

I wonder especially as my signal strength seems to be stronger at night and in that case the signal is also much more stable. Is that a counter-indication of overload?

This is a good indication that you need a higher gain antenna.

Quote:
Originally Posted by kovax View Post

I notice in the pictures that the antenna was angled up. Is that because that location was in a valley? My view is essentially flat to the horizon. Do I need to be angled down or is that just knit picking at this point?

Aim for the horizon.
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post #11885 of 16297 Old 10-11-2009, 06:58 PM
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If you put the loop in a Faraday Cage, you could point the antenna at the main transmitter on Stone Mt. GA and probably get good results (unless the local transmitter is very close and has a good signal strength, then point it there). Without some sort of protection from one of the transmitters, the loop will not help.
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post #11886 of 16297 Old 10-11-2009, 07:04 PM
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RocketGuy3, I still think you would have a solid setup using a VHF-High antenna with your 4228 and run the coax from both through the UVSJ (See above post #10416).
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post #11887 of 16297 Old 10-11-2009, 08:29 PM
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Quote:
Originally Posted by systems2000 View Post

If you put the loop in a Faraday Cage, you could point the antenna at the main transmitter on Stone Mt. GA and probably get good results (unless the local transmitter is very close and has a good signal strength, then point it there). Without some sort of protection from one of the transmitters, the loop will not help.

Are saying the two signals are canceling each other out? The Stone Mt. ch 8 is 70 miles away at 228 degress 21 kw, the local is 4.6 miles away .150 kw at 334 degress los. tv fool says co-channel is possible. In gptv's orginal request for a local ch they ask for and got dt 10... I protested that it would kill WXIA dt10 out of Atlanta, to my surprise they ask for and received a switch to ch 8. I am not in the Atlanta dma, so they could have stayed with dt 10 but didn't which I appreciate, but sounds like they have a problem. Of course I am one of a handful of people in my town that would ever notice.

P S I turned my ya1317 away from Atlanta, and toward the local ch 8 got 100 strength, but the signal continued to pop in and out.

Tired
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post #11888 of 16297 Old 10-11-2009, 09:06 PM
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Originally Posted by 300ohm View Post

Yep, but let me double check that with modeling. Is your DB2 the one with 1" X 4" mesh behind it ?
And actually, a 23" - 24" loop with combiner may be a more compact indoor solution for you as well. Especially if the vhf-hi channel is in a different direction from the uhf ones. The DB2 would fit inside the loop.

According to the measurement I just took, it's about 1" X 2.75", but I'll give that idea a try once I move. If that doesn't work, and/or the signal there is any weaker than it is now, I think I might just go all out and get an HD8200U and stick it in the attic. It's a bit more than I wanted to spend, but I'm pretty sure it'd cover all my bases.
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post #11889 of 16297 Old 10-11-2009, 10:02 PM
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dagger, the Quantum FX ANT 101 is a better antenna on both UHF and VHF HI, and VHF Low, than the Winegard SS 3000.

However it is a better than average indoor antenna. Seems like it will work for you, on a tricket shelf.

The Winegard SS3000 is into the -10 dBd range on VHF Hi (then add 10db amplification). The FX ANT 101 is about 0 dBd then add 36 db amplification. However you really should just be adding 3 dB amplification on either of them for the amplifier....but that gets a bit complicated.

Simply put the QFX ANT 101 is about 10 dB better than the Winegard SS3000 on VHF High.

If the Winegard ends up being unsatisfactory, there are options.

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post #11890 of 16297 Old 10-12-2009, 12:55 AM
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I had the information from tvfools.com up before but here it goes again, I'm only 13 miles form the city and something must have changed to take all the vhf channels away.


http://www.tvfool.com/?option=com_wr...03fb5cc5507be4
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post #11891 of 16297 Old 10-12-2009, 02:07 AM
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dagger,

Take another look at your Chart, your ABC/WABC, PBS/WNET and CW/WPIX are VHF stations. An Antenna is chosen to fulfill the channels in the "REAL" column. You have a couple other VHF stations available, but, I'd suggest you aiming for your 290°-304° Farms.
Given your overall low signal strength, you'd be better off with a Rooftop Antenna and a Pre-Amp. Can you do that?

Good Golf, Good HD'ing, and anything else that makes you happy ! :-)
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post #11892 of 16297 Old 10-12-2009, 06:30 AM
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Quote:
Originally Posted by holl_ands View Post

VHF has difficulties penetrating into
modern homes due to the use of chicken wire in stucco and aluminized foil "wraps",allowing BETTER penetration of UHF freqs via window openings.

HOWEVER, I have also seen specs wherein modern "Low-E" glass attenuates UHFby about 20 dB (but no data wrt VHF!!!!).

IMO your link on free-space path loss (FSPL) is somewhat unrelated to the subject of penetration. We are more interested in trees, walls, and roofs than vacuum.

I'm an EE working with RF for over half century but must admit OTA TV is not my area of specialty. And RF, particularly high-frequency, can be very peculiar and unpredictable. But myself and most others in the field generally accept that low frequencies have much better penetration.

A RS S90 UHF/VHF yagi, when it was in the attic under asphalt roof, pulled in two VHF stations well but pretty much zilch on UHF. I cut off the small UHF yagi with it's reflector (1 minute job w/hacksaw) and mounted it on a pole outside the window. Suddenly 30 some additional UHF stations. Just for yucks I swapped positions and guess what? UHF back down the drain again.. little change in VHF. Both bands contain stations with similar TVfool strengths. This summarizes my only experience with TV reception and penetration.

Can't say too much about aluminized insulation or stucco grid other than mesh size is very wavelength dependent. Thick solid metal effects all frequencies similarly as far as penetration.

I do have significant experience with effects of glass on 72mhz, FMS/GMRS, GPS, FTA sat, XBee (900 and 2400), WiFi, etc.. I found glass will attenuate high frequencies far more than low. At least until you get past IR up into the visible. Try getting WiFi or FTA through a window. Much less of a problem with 72mhz or 400mhz.

My general impression is high frequencies are LOS with poor penetration while low is better at cutting through trees and roof. Of course UHF may be "better" from antenna size viewpoint but that's another subject.
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post #11893 of 16297 Old 10-12-2009, 07:41 AM
 
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Quote:
Originally Posted by john warfin View Post

To some the laws of physics are merely a suggestion.

Hey Einstien signals that have the most issues with indoor reception

1) Low-VHF
2) High VHF
3) UHF

Using your logic the opposite is true. Also it's amazing how my wireless G signal coming from my router that's at 2300 MHz( 3.5-5 times higher than the UHF TV band ) can be picked up in a house made of brick over 250 feet away. Amazing how cell phone signal can penetrate buildings. What frequency are they on again?

As some other guy said it's about the power levels. You just can't generically state that VHF can penetrate better than UHF without any other info.
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post #11894 of 16297 Old 10-12-2009, 08:25 AM
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Quote:
Originally Posted by BCF68 View Post

Hey Einstien signals that have the most issues with indoor reception

1) Low-VHF
2) High VHF
3) UHF

Using your logic the opposite is true. Also it's amazing how my wireless G signal coming from my router that's at 2300 MHz( 3.5-5 times higher than the UHF TV band ) can be picked up in a house made of brick over 250 feet away. Amazing how cell phone signal can penetrate buildings. What frequency are they on again?

As some other guy said it's about the power levels. You just can't generically state that VHF can penetrate better than UHF without any other info.

Yes I can. Watch this:

"VHF can penetrate better than UHF"

Here, it is again, twice in a row:

"VHF can penetrate better than UHF"
"VHF can penetrate better than UHF"



Apparently you've choosen to ignore my comment about "all else equal" (including power level). And then proceed to ignore it in your own examples.

"Lisa... In this house we OBEY the laws of thermodynamics" -Homer Simpson
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post #11895 of 16297 Old 10-12-2009, 08:30 AM
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Quote:
Originally Posted by Don F. View Post

Are saying the two signals are canceling each other out?

At those directions, power levels, and distances, it's very possible. Your P.S. statement is another good indicator.

NOTE: I originally posted: "Without some sort of protection from one of the transmitters, the loop will not help." Maybe I should have said "…the loop may not help."
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post #11896 of 16297 Old 10-12-2009, 08:39 AM
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Quote:
Originally Posted by BCF68 View Post

Also it's amazing how my wireless G signal coming from my router that's at 2300 MHz( 3.5-5 times higher than the UHF TV band ) can be picked up in a house made of brick over 250 feet away.

BTW IEEE 802.11g is 2400mhz not 2300mhz.
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post #11897 of 16297 Old 10-12-2009, 10:48 AM
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Oops, I meant the Quantum FX ANT 102 is a better antenna than the Winegard SS3000 on VHF LO and HI and UHF.

Vizio VP322 Plasma / Vizio GV42LF LCD / Denon 2200 Silicon Image DVD / Panasonic S97 Faroudja Genesis DVD / Oppo 970HD Mediatek DVD / Oppo 983H Anchor Bay DVD / Panasonic LX-600 Laserdisc / Aiwa MX100 Multi-region VCR / JVC S7600 S-VHS / PS2 / Sega Genesis / Nintendo SNES / Roku 2 XS & HD-XR / Realistic STA-90 Reciever / Realistic Minimus 7 / Antennacraft G1483 Hoverman / Belden 7915A RG6 / Channel Master 7777 Titan 2 UHF/VHF / Panasonic AX-200u / Optoma Graywolf 92" / Draper Luma 92"
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post #11898 of 16297 Old 10-12-2009, 01:22 PM
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I just dropped my DISH and am going to try the OTA thing. I'm in Hopkinsville, KY and am primarily looking to pick up stations out of Nashville about 55 to 65 miles away. I would really like to try an attic mount in my single story house and avoid mounting some beast 15 feet over my house if at all possible. The terrain between me and the towers is not terribly hilly. There are some fairly large trees in my yard and neighborhood but no tall buildings or other structures.

I have run an analysis on the tvfool.com website and a link to the results is below. I really only want to pickup the Nashville stations in the 135 to 146 degree range. Any suggestions on what equipment might work best for me would be greatly appreciated!

www[dot]tvfool[dot]com/?option=com_wrapper&Itemid=29&q=id%3d03fb1f9efaaa35
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post #11899 of 16297 Old 10-12-2009, 02:37 PM
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Quote:
Originally Posted by jausenbaugh View Post

I just dropped my DISH and am going to try the OTA thing. I'm in Hopkinsville, KY and am primarily looking to pick up stations out of Nashville about 55 to 65 miles away. I would really like to try an attic mount in my single story house and avoid mounting some beast 15 feet over my house if at all possible. The terrain between me and the towers is not terribly hilly. There are some fairly large trees in my yard and neighborhood but no tall buildings or other structures.

I have run an analysis on the tvfool.com website and a link to the results is below. I really only want to pickup the Nashville stations in the 135 to 146 degree range. Any suggestions on what equipment might work best for me would be greatly appreciated!

www[dot]tvfool[dot]com/?option=com_wrapper&Itemid=29&q=id%3d03fb1f9efaaa35

If you can get it in your attic (I wouldn't bother!), a large, full-band antenna such as the WG 8200 HD (or similar) would be suggested.

I wouldn't give an attic install high odds of being successful with those forecast numbers...
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post #11900 of 16297 Old 10-12-2009, 02:52 PM
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[quote=systems2000;17339969]At those directions, power levels, and distances, it's very possible. Your P.S. statement is another good indicator.

The Stone Mt. signal is booming in today with no sign of the local. I haven't recieved a reply from Ga. Public tv to my inquiry about the problem. Today being Columbus Day they are probably closed. That "box" may be the only solution, unless they make a change, don't know what that would be.
Thanks for your help and 300....

Tired
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post #11901 of 16297 Old 10-12-2009, 04:17 PM
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Quote:


I wouldn't give an attic install high odds of being successful with those forecast numbers...

Yeah, at 55 to 65 miles away, (about my distances) youll need all the signal you can get. You lose anywhere from 6 to 25+ db in the attic. The trees are another problem. Even with an outdoor install, you will want a clear path to the transmitter of at least a few hundred feet.
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post #11902 of 16297 Old 10-12-2009, 04:26 PM
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Quote:
Originally Posted by systems2000 View Post

RocketGuy3, I still think you would have a solid setup using a VHF-High antenna with your 4228 and run the coax from both through the UVSJ (See above post #10416).

I have the DB2, not the CM4228, but same thing I suppose. Do you have any recommendations on a good, high-gain VHF-high antenna? I can't seem to find much middle ground on VHF antennas -- it looks like I have to choose between either bunny ears with a loop (which don't seem to cut it in my area) or massive, $100+ outdoor/attic antenna. That's why I was mentioning the HD8200U earlier.
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post #11903 of 16297 Old 10-12-2009, 05:04 PM
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Quote:
Originally Posted by RocketGuy3 View Post

I have the DB2, not the CM4228, but same thing I suppose. Do you have any recommendations on a good, high-gain VHF-high antenna? I can't seem to find much middle ground on VHF antennas -- it looks like I have to choose between either bunny ears with a loop (which don't seem to cut it in my area) or massive, $100+ outdoor/attic antenna. That's why I was mentioning the HD8200U earlier.

The Winegard YA-1713 is supposed to be one of the better VHF-high antennas with raw gains in the 8-10 dBd range. It's not quite as good as the HD8200U or other large outdoor antenna's (~2-3db less), but costs considerably less and should do quite a bit better than Rabbit Ears. Personally, I didn't have much luck with it, but considering I was trying for an attic mount to pick up a 2Edge diffraction station 65 miles away, it was a long shot. At some point, I'll probably see how it does up on the roof, but I haven't had any time recently.
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post #11904 of 16297 Old 10-12-2009, 05:30 PM
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Hmm, that does seem like a pretty good option. I guess one of those combined with my DB2 using one of these should do the trick?

http://www.solidsignal.com/pview.asp...iners&sku=UVSJ

Given that the antennas are on different bands, I wouldn't have to worry about any phasing problems, right? Will this combiner isolate the proper bands from each antenna?
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post #11905 of 16297 Old 10-12-2009, 05:52 PM
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Here's H&E paper (sec 6) citing a 1963 report that says NYC penetration loss is HIGHER for VHF than UHF:
http://www.copyright.gov/docs/shvera...r-attach-B.pdf
Note that it mixes antenna height in with penetration loss, so it's hard to separate....
Counterintuitive? Yes. Accurate? Hard to say without access to the actual studies.
Unfortunately, recent studies in Europe have omitted VHF, cuz they apparently don't use it anymore....

Here's an example of current experts citing higher building penetration loss at VHF than UHF:
http://www.acrodyne.com/PDF/Portable_Means_Power.pdf

BTW: The free space loss equation was intended to show that it takes much less power at VHF
to provide the same receive signal strength as at UHF. This is the first step in determining
the DIFFERENCES between VHF and UHF, the others being antenna Gain (& VSWR Losses),
Penetration Loss and several others (Foliage Loss, Clutter Loss, et. al.)

====================================================
FYI: I posted links to (mostly UHF) Indoor Penetration Loss and Antenna Height Gain studies here:
http://www.avsforum.com/avs-vb/showt...php?p=14035356

There is a more recent report on a very extensive indoor loss (and antenna height)
field test for UHF TV and summarizes results for some Cell Phone frequencies:
"Extensive Penetration Loss Measurements and Models for Different Building Types
for DVB-H in the UHF Band, Plets, Verloock Martens Gauderis & Deventer,
IEEE Trans on Broadcasting, Vol55 No2 Part I of II, June 2009 ":
http://ieeexplore.ieee.org/Xplore/lo...hDecision=-203

Test area was Ghent, Netherlands collecting data on a variety (100 total) of building types.
Results for more modern buildings may be higher due to use of foil wraps and Low-E glass.
For example, "Coated" Office Buildings had 20-25 dB loss on first two floors.

It also has a very useful list of references. Tables III & VI summarize 602 MHz results:
Normal House (aka "Mansion"): 8.2 dB (standard deviation = sigma=3.7 dB).
This is consistent with Apartment results, although with a much higher sigma.
[PS: Table III Total for Apartments is clearly in error.]
Literature average cited for House: 11 dB (sigma= 6 dB).

Penetration Loss decrease with increasing antenna height was also measured.
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post #11906 of 16297 Old 10-12-2009, 07:10 PM
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Quote:
Originally Posted by RocketGuy3 View Post

Hmm, that does seem like a pretty good option. I guess one of those combined with my DB2 using one of these should do the trick?

http://www.solidsignal.com/pview.asp...iners&sku=UVSJ

Given that the antennas are on different bands, I wouldn't have to worry about any phasing problems, right? Will this combiner isolate the proper bands from each antenna?


Yes, that is the purpose of a UVSJ (aka UHF/VHF diplexer).

Modest physical size high-VHF antennas include the 5-element Yagis from Antennacraft and ChannelMaster (both inexpensive) or the new C5 from Antennas Direct that is a loop-in-front-of a reflector.

One thing I've noticed about the C5 is that is does a fair job on certain UHF channels. I've measured gain (referenced to a dipole) of between -5 and + 5 dB depending on the channel in use. The response curve has a bit of a roller-coaster curve to it on UHF.... Of course, it's bigger (has to be so it will be resonant at high-VHF) than a DB2 and it's a lot more expensive.

BTW, we haven't seen your TVfool data. That would be quite helpful to have in hand when giving specific advice.
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post #11907 of 16297 Old 10-12-2009, 08:09 PM
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post #11908 of 16297 Old 10-12-2009, 11:48 PM
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Here's my tvfool. Looks like just about everything I want is in that ~200 degree area.

http://www.tvfool.com/?option=com_wr...03fbcdecc582ff

The signals look stronger than they seem to have been for me so far, but maybe just an attic mount can fix that. I'll probably give the DB2/1713 combo a try.
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post #11909 of 16297 Old 10-13-2009, 05:19 AM
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The 1713 is probably overkill with numbers like those. Plus, keep its physical size in mind as to how it might fit in your attic (or not).

I'd try one of the mid-range high-VHF antennas first.

You're right - "Stupid ABC!"
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post #11910 of 16297 Old 10-13-2009, 06:07 AM
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[quote=holl_ands;17343477]Here's H&E paper (sec 6) citing a 1963 report that says NYC penetration loss is HIGHER for VHF than UHF:
http://www.copyright.gov/docs/shvera...r-attach-B.pdf
Note that it mixes antenna height in with penetration loss, so it's hard to separate....
Counterintuitive? Yes. Accurate? Hard to say without access to the actual studies.
Unfortunately, recent studies in Europe have omitted VHF, cuz they apparently don't use it anymore....

Here's an example of current experts citing higher building penetration loss at VHF than UHF:
http://www.acrodyne.com/PDF/Portable_Means_Power.pdf
QUOTE]


Thanks for those links (let's face it you are go-to guy in that dept.). Very educational. I read and saved them to disk. However the Dishnetwork guys never provide UHF/VHF links or actual data but simply state:

"The largest impediments to the adoption of M/H service by VHF stations are the inferior gain of small handheld device antennas and, perhaps counter-intuitively, the increase in building penetration losses at these lower
frequencies. Both impediments are based upon the relative size of receive antennas and building apertures, such as outside windows, compared to the wavelength of the signal."

The fact that they use the term "counterintuitive" at all bolsters my point that with RF in general low freq has a rep for better penetration. And, again, my own experience dealt with attic and roof issues instead of antenna size and windows which seem to be the major factors in their conclusion.

The Sinclair/Acrodyne paper also states that building penetration is better for UHF but provide little basis other than referring to Bendovs site which seems more concerned with interference and hardware design.

It's true most of my "intuition" regarding TV comes from years of experience with other wavelengths. And maybe I'm biased because it's much harder to put the VHF antennas outside and allow little UHF ones indoors. My own experiment showed the opposite however. It would be interesting if others repeated a similar test (attic/roof not antenna size/apertures etc.).

May just be TV wavelengths have decided laws of physics are merely suggestions.
john warfin is offline  
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