[PoppaDigital]

Am I in the correct group for Vhf inhanced Hoverman ? Ive lurked in the I & II group for a few weeks and I want to explore making my own antenna but would require vhf high for the most or all networks depending on how I aim it. My USA Zip is 12601 if you care to check TVFool to see. Ive have checked the Nec2 sostware, but can't make heads or tails of it, as I'm just a dumb Bus Driver. If this seems too much I'm sorry, but I've played on usenet and that wasn't pretty.

 

[300ohm]

Am I in the correct group for Vhf inhanced Hoverman ?

The Hoverman is a UHF only antenna. Looking at your TVFool, youll have channels 6, 7 and 12 and 13 digital stations after next February, and the signals are very very weak (over -100dbm). Youre going to need a commercial Deep Fringe VHF/UHF combo antenna mounted fairly high with a preamp. Only your channels 27 and 48 will be easy to get.

Or if youre not concerned about channel 6, you can still build the Gray-Hoverman, get a channel 7 to 13 high gain antenna that takes up less space than a vhf-low one does and is cheaper, and combine the 2 using a Channel Master 0264DSB pre-amplifier. Of course, high mounting would still be a must.

 

[jdogmoney]

The Hoverman is a UHF only antenna

It's funny, I just built a SBGH yesterday and my best channel is analog vhf 2.
Only thing is, ch2 is only 10 mi away and transmits at 4-5000kw. So I'm sure that's why I pick it up so well. I could probably pick it up with a paper clip in the coax input!

 

[tvlurker]

Only thing is, ch2 is only 10 mi away and transmits at 4-5000kw.

There are no VHF-Low band stations above 100 kW that I know of. Are you thinking of:

Greensboro, NC WFMY-TV 100.0 550.8 - H 35°52'13"N 79°50'25"W TV-LIC CBS

But 10 miles away is pretty close, and TVFool predicts a level in the -27.5 dB range. Even if the antenna has 50 dB of loss at channel 2, you'd still get it!

I can get -50 dBm UHF DTV stations with a paper clip, so I'm not surprised at your analog channel 2 at -27.

 

[PoppaDigital]

re-The Hoverman is a UHF only antenna ?

I found this @ http://www.qsl.net/va3rr/hdtv/hoverman.htm and it was my hope that adding 2 horzontal 420mm rods at the feedpoint, as on the Winegard HD-1080 would do the trick. I barely have room for DBGH in the atic (30' up), and plan on a split screen reflector in hopes that that would increase the gain ever so slightly.

CM Hoverman UHF antenna modifications of Hoverman patent 3,148,371 for digitalhome.ca
CM ==================================================================================
CM
CM Modified Hoverman for VHF(Ch7) and UHF(Ch 14-51)- FullWave Rod Reflectors
CM
CM Original nec file supplied by old Sparks
CM This modified nec file by Autofils models the following parameters:
CM
CM Length of each diagonal sub-section = 7.07 inches
CM Gap at feedpont = 1.75 inches
CM Length of horizontal sub-sections changed!! It was reduced from patent value of 7 inches to 5 inches
CM FullWave rod reflectors with a gap of 0.78 inches and with the following lengths
CM - Top and Bottom = 0.82meters
CM - Middle = 0.66 meters
CM - Reflector Spacing = 0.1148 meters (4.52 inches)
CM
CE
GW 1 5 0 0.02223 0.00000 0 -0.02223 0.00000 .0015
GW 2 10 0 0.02223 0.00000 0 0.1492 0.127 .0015
GW 3 10 0 0.1492 0.127 0 0.02223 0.254 .0015
GW 4 10 0 0.02223 0.254 0 0.1492 0.381 .0015
GW 5 10 0 0.1492 0.381 0 0.2762 0.381 .0015
GW 6 10 0 0.02223 0.00000 0 0.1492 -0.127 .0015
GW 7 10 0 0.1492 -0.127 0 0.02223 -0.254 .0015
GW 8 10 0 0.02223 -0.254 0 0.1492 -0.381 .0015
GW 9 10 0 0.1492 -0.381 0 0.2762 -0.381 .0015
GW 10 10 0 -0.02223 0.00000 0 -0.1492 0.127 .0015
GW 11 10 0 -0.1492 0.127 0 -0.02223 0.254 .0015
GW 12 10 0 -0.02223 0.254 0 -0.1492 0.381 .0015
GW 13 10 0 -0.1492 0.381 0 -0.2762 0.37716 .0015
GW 14 10 0 -0.02223 0.00000 0 -0.1492 -0.127 .0015
GW 15 10 0 -0.1492 -0.127 0 -0.02223 -0.254 .0015
GW 16 10 0 -0.02223 -0.254 0 -0.1492 -0.381 .0015
GW 17 10 0 -0.1492 -0.381 0 -0.2762 -0.381 .0015
GW 19 10 -0.1148 -0.41 0.381 -0.1148 0.41 0.381 .0015
GW 21 10 -0.1148 -0.33 0.127 -0.1148 0.33 0.127 .0015
GW 23 10 -0.1148 -0.33 -0.127 -0.1148 0.33 -0.127 .0015
GW 28 10 -0.1148 -0.41 -0.381 -0.1148 0.41 -0.381 .0015
GE 0
GN -1
EK
EX 0 1 3 00 1. 0.
FR 0 35 0 0 450 10
RP 0 1 10 1510 90. 0. 0. 20. 0. 0.
EN

So far I haven't figured out how to add the 2 elements to the model to run it to see they triple the gain as Winegard claims it dose on the HD-1080

 

[300ohm]

and it was my hope that adding 2 horzontal 420mm rods at the feedpoint

Been there, done that, so I can save you some time.

I took apart an old set of rabbit ears, drilled out the ends a little more to fit my screws and bolts, and attached it to my DBGH and experimented with it at the feedpoint and other locations in various lengths and positions. The best I could do was to get channel 6 about as good as rabbit ears. But no matter what I tried, I couldnt get channel 12 to perform as well as rabbit ears by themselves.

Quote:
Only thing is, ch2 is only 10 mi away and transmits at 4-5000kw.

There are no VHF-Low band stations above 100 kW that I know of.

Very true. If that channel 2 was actually transmitting at 5000kw, I could probably pick it up with a paper clip in Delaware, and tvlurker could easily get it in Ontario with a SBGH, heh.

 

[jdogmoney]

There are no VHF-Low band stations above 100 kW that I know of. Are you thinking of:
Greensboro, NC WFMY-TV 100.0 550.8 - H 35°52'13"N 79°50'25"W TV-LIC CBS

Very true. If that channel 2 was actually transmitting at 5000kw, I could probably pick it up with a paper clip in Delaware, and tvlurker could easily get it in Ontario with a SBGH, heh.

Sorry, not channel 2. Channel 20 is transmitting at 4821kw and is only 8.7 mi from me. I see what you're saying about vhf not transmitting at such a high power. But it is vhf ch 2 that I'm getting so well.

By the way, after the 2-17-09 transition will stations on the uhf band start upping their transmitting power on their digital channel. I noticed my analog uhf ch 26 out of Winston-Salem is putting out 4978kw. But the digital one is only at 197kw. It shows going up to only 373kw after the february transition. Why wouldn't they keep their 4978kw power for digital broadcasting?

Hey 300ohm, make sure you read my post I'm about to make on the generation I thread.

 

[tvlurker]

There are no VHF-Low band stations above 100 kW that I know of.

Now I have to correct myself. I *do* know about channel 3 in Edmonton. (but it's only 300 or so kW)

 

[tvlurker]

Why wouldn't they keep their 4978kw power for digital broadcasting?

Because they don't need to. You only need 15dB above the noise floor to get a perfect picture with DTV. 15 dB above the noise floor gets you a snowy picture with NTSC. The maximum for UHF DTV in the US is 1MW, and that's often used to replicate a VHF-Low station on UHF.

Using more power than you need causes interference with other stations, and would make fewer channels available for broadcasting.

Why did they only ask for 373 kW? You'd have to look at the engineering documents for their application to maximize to the FCC (it's all available online) to know for sure. From the apps I've looked at, the power chosen is either:
1. the maximum for that class of station in that particular zone of the country at their transmitter's height. (see WMTW-DT 8 Poland Spring Me)
2. the most they could ask for without extending more than five miles beyon their "appendix B" allocation (most stations)
3. The most they could ask for without causing more than a 0.5% increase (by population) in interference to another station. (see WWNY-DT 7 Carthage)

TVl

 

[300ohm]

Also look at the new TVFool update that was done 6/27/2008. In my case, some of the stations quadrupled their proposed power from the March 2008 TVFool listing I had. I gives me 3 to 9+ more dbm than was originally proposed. Because of the nature of the "cliff" effect on DTV (its all or nothing), I knew they had seriously underestimated the original power requirements, at least for my area.

 

[rochmndx]

FWIW,
TV Fool takes into account the polar pattern if the station is using a directional antenna, and predicts how much power is coming your way. That's why you have such odd numbers. For instance, TV Fool gives me an ERP of 955.58KW for one of our 1MW stations.

 

[300ohm]

That's why you have such odd numbers. For instance, TV Fool gives me an ERP of 955.58KW for one of our 1MW stations.

Yeah, I have a 998.13 KW station. I originally thought they did that to have a safety margin to avoid FCC fines for going over the limit, heh.

 

[zjts]

All the UHF cahnnels in my area are in the lower UHF range. Is there any chance the new Generation II Gray-Hoverman Antenna design will be posted soon?

 

[300ohm]

Hopefully.

 

[b1gmoose]

Ch 2 Yagi?

So I'm new to antenna stuff and have played around with things a bit. I know that in 2011 CBMT will be gone from Ch 2. But, for the time being, does anybody have the approximate dimensions I would need to build a yagi?

I found a link (http://www.anarc.org/wtfda/hafsb54.pdf) but that thing is a monster. Could 1 be made smaller? Say a reflector, driven element, director, and 1 element? Or maybe I could make it for Ch 3?

I've had some success with Ch 2 with rabbit ears, but even outside, the signal is quite snowy.

thanks for the help,

~ryan

 

[Yagi]

I suppose you mean CBFT-2 and not CBMT which is on channel 6. I'm afraid a channel 2 Yagi is always a big antenna. Where are you located ? Is channel 9 in Sherbrooke or channel 13 in Trois-Rivières a viable alternative for SRC ?

 

[stampeder]

That is true because a full Channel 2 wave is about 18 feet! About the only sane way to build for it is half-wave or quarter-wave.

 

[Yagi]

And I should add that when all TV stations will have migrated to digital, channels 2 through 6 will no longer be used for TV. Channel 3 Burlington VT will cease broadcasting on this channel in February 2009. In Canada, the cut-off date is 2011. I would not invest in a channel 2 antenna.

 

[b1gmoose]

A 1/4 wave yagi might work. I've got tons of scrap metal around the house and I could build one. I just don't know the dimensions I would need to use.

I get 7, 9, and 11 out of Sherbrooke. I'm located a little south of St. Johnsbury, VT at 550' elevation, right on the passumpsic river.

Ch 2 or 6 out of Montreal would be nice. It's not for me, but for the Wifey and kids. I don't understand more than 3 words in french, but they are my the translators for me when we go north. Ch 11 I like, it's in english.

I know things are moving in 2011, but for now, to get them by until we move to a better location next fall ontop of a hill and not in a valley.

I've had to go to extreme measures just to get WVNY on VHF-13 40 miles away. All other stations on Mt. Mansfield come in just fine.

 

[300ohm]

A 1/4 wave yagi might work. I've got tons of scrap metal around the house and I could build one. I just don't know the dimensions I would need to use.

1/4 wave yagis generally dont work so well. 1/2 wave yagis are the common ones. As for calculating the dimensions, you can go to an online yagi calculator like the one linked in mlords thread or you can download an easy to use program called Yagi Calculator by John Drew. Just google for it. Then you can play around with calculating shorter dimensions and see the gain.

And I should add that when all TV stations will have migrated to digital, channels 2 through 6 will no longer be used for TV.

I wish that were true, but Ive never heard anything that my oddball pain in the neck channel 6 in Philadelphia will be eventually migrating. Do you have any firm info on this ?