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Discussion Starter #1
Hi,

This is my first post so be easy on me. I've been reading about the GHSB for a while and only discovered this forum a couple of days ago. I'd like to build a bi-directional antenna for both UHF & VHF-Hi to keep in my attic (so I guess I want to lose the reflectors and keep the top hat?). Bi-directional could give me a shot at a 2edge VHF-Hi channel 13. Here is my tvfool: http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d3cf402ff846865

My current setup is two antenna's in the attic, one is an old rabbit ears and UHF loop and the other is a fractal DB4 that I built. They are attached via a combiner to two tvs. My reception currently is good for all my green channels except for 29 (Fox) & 43 (NBC). Those channel sometimes mess up and I think it may have something to do with two antennas in the attic covering the same area.

I was thinking about going with the GH0n - reflectorless with hat narod (slanted top hat - post #186) or something more with the straight top hat like below.

CE
GW 1 23 0 -2.1588583 0 0 -7.6152756 5.45644094 0.125
GW 2 23 0 -7.6152756 5.45644094 0 -2.2701969 10.8015236 0.125
GW 3 23 0 -2.2701969 10.8015236 0 -7.5596063 16.0909291 0.125
GW 4 15 0 -7.5596063 16.0909291 0 -12.284016 16.0909291 0.125
GW 13 7 0 -8.7969685 18.450937 0 -8.7969685 16.5631417 0.125
GW 14 13 0 -8.7969685 16.5631417 0 -13.244331 16.5631417 0.125
GW 21 23 0 2.15885827 0 0 7.61527559 5.45644094 0.125
GW 22 23 0 7.61527559 5.45644094 0 2.27019685 10.8015236 0.125
GW 23 23 0 2.27019685 10.8015236 0 7.5596063 16.0909291 0.125
GW 24 15 0 7.5596063 16.0909291 0 12.2840157 16.0909291 0.125
GW 33 7 0 8.7969685 18.450937 0 8.7969685 16.5631417 0.125
GW 34 13 0 8.7969685 16.5631417 0 13.2443307 16.5631417 0.125
GW 10 53 0 8.7969685 18.450937 0 -8.7969685 18.450937 0.125
GW 41 23 0 -2.1588583 0 0 -7.6152756 -5.4564409 0.125
GW 42 23 0 -7.6152756 -5.4564409 0 -2.2701969 -10.801524 0.125
GW 43 23 0 -2.2701969 -10.801524 0 -7.5596063 -16.090929 0.125
GW 44 15 0 -7.5596063 -16.090929 0 -12.284016 -16.090929 0.125
GW 53 7 0 -8.7969685 -18.450937 0 -8.7969685 -16.563142 0.125
GW 54 13 0 -8.7969685 -16.563142 0 -13.244331 -16.563142 0.125
GW 61 23 0 2.15885827 0 0 7.61527559 -5.4564409 0.125
GW 62 23 0 7.61527559 -5.4564409 0 2.27019685 -10.801524 0.125
GW 63 23 0 2.27019685 -10.801524 0 7.5596063 -16.090929 0.125
GW 64 15 0 7.5596063 -16.090929 0 12.2840157 -16.090929 0.125
GW 73 7 0 8.7969685 -18.450937 0 8.7969685 -16.563142 0.125
GW 74 13 0 8.7969685 -16.563142 0 13.2443307 -16.563142 0.125
GW 50 53 0 8.7969685 -18.450937 0 -8.7969685 -18.450937 0.125
GS 0 0 0.0254
GE 0
EK
LD 5 0 0 0 2.49e7 0
EX 0 100 1 0 1 0
GN -1
FR 0 1 0 0 800 0
RP 0 60 73 1001 0 0 3 5

What do ya'll think? Any input would be greatly appreciated. Thanks!

LordCy
 

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Discussion Starter #2
bumping myself - GH0n build

Didn't hear anything back from anybody on this forum so I just decided to build the GH0n with no reflectors ("Top Hat" forum post # 186). I'm still only getting the green channels from my tvfool report but I'm only using 1 antenna now. Only channel that may be a problem is my local PBS which is channel 11 on VHF-Hi. On my TV, it teeters between 3 & 4 bars (about 60-65%). In case anyone is interested, here are the dimensions and some pics of my build. It's not perfect but I'm also not an expert.



Thanks.

LordCy
 

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Hi lordcy,

Nothing like diving in and trying a build to get you addicted to playing with antennas. The amount of information on this site can be overwhelming.

One thing I think I see in your picture is that you have a wire connecting across the feed point where the balun attaches at the center of the antenna. In the model, this wire is depicted as having a red circle in the middle and it just represents where the antenna feed line should be connected, not where a wire should be placed. By placing a wire there, you are actually shorting the signal between the two sides of the antenna instead of forcing it to go through the balun and down the coaxial cable to your receiver. So remove the wire and just leave the balun connected across the feed points and see if your results improve.

Have fun!
 

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Correct, thats not a wire at the feedpoint.

I'm still only getting the green channels from my tvfool report
Thats all you can reasonably expect even with the highest of gain antennas. You have a very sharp cutoff, going from +38.6 NM to -2.1 NM on the next station down. Negative NM, 2 edge stations, require extraordinary efforts and costs to get.
On the other hand, since the south experiences a lot of tropos, youll frequently get negative NM stations, just not day in and day out.
Only channel that may be a problem is my local PBS which is channel 11 on VHF-Hi
At 81.2 NM, youre most likely overloading. Try an attenuator or adding some very long lengths of coax or adding a splitter and see if reception improves.
 

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Discussion Starter #5
appreciate the help!

Thanks, both of you. I'll try to remove the middle wire and see if the reception improves. Regarding the long wire, I am already doing that since I realized that I may be too close to the stations around me. I'll let you know the results when a get a chance to do it later tonight. Again, thanks!
 

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If you are up for another build, you could try the M4 with no reflector here. I made one with #10 wire and PVC for outside use. It requires some soldering but is otherwise easy to construct.
 

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At over 70 NM for your main network stations, I would like to see you stick a large paper clip into the F connector on the TV and see how many stations you get. :p
 

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Almost all UHF channels, all pretty much in two opposite directions, all very close by and powerful, all LOS line of sight. Only one ch, 11, on VHF hi.

Try just one small UHF loop in the attic.
(a small UHF loop I've tested, picks up VHF hi pretty good too, even though not officially designed for that)

Point it broadside at 60 deg from North, sort of right at your channel 42. Experiment aim a little either way with all channels.
I figure it'll catch everything nearby aimed that way, from front and back.

If you need more attenuation ... try a quality splitter that has more outputs.
Some splitters... with four outputs, are 8db down on 3 of the four outputs.

Proper 75 ohm terminations on all the un-used outputs may help increase attenuation - if you need more attenuation, and proper terminations will also prevent bad results from signal reflections from open outputs, on the splitter, and up and down the line. Proper terminators on un-used taps are generally a good idea / good practice.

[ there's real, in-line attenuators too, if you need one ... various drops ... not sure where you'd find them in your area. ]

Aside: As for getting that far off ch 13, 2 edge, -ve noise margin, 76.2 mile distant one? Ya, that may be a bit of a challenge. With all the powerful other stuff nearby around.

Well ... at least there's no adjacent or no co-channel warning beside ch13 on your TV-fool. At least it's VHF Hi - signal should bend a little better, round those 2-edges than UHF.

Separate, high directivity antenna permanently pointed right at 13. Outside high up clear of everything.
( Channel cut yagi ? For one Channel ? or VHF Hi only dedicated Yagi )
( Bandpass filter for one channel, channel 13 ?) (Good low noise, VHF hi only pre-amp ?)

You could spend money and effort ... and not get results on 13 ... or get intermittent results. No guarantees with that one.

(I really hate to say this ...Is it available on basic cable in your area ?)
(no ... on second thought .... don't go there.)

P.S. I started a UHF Loop thread in the Antenna Research & Development section. If you want to check out results with simple uhf loop.
 

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Discussion Starter #10
removed middle wire

I removed the middle wire tonight so that only the transformer is connected there. With that done, I now get channel 11 at 4-5 bars constant with no changes on the rest of the channels (but no additional channels).

I have tried the paperclip and the only channels I don't get is 47 & 24. The rest are 4 bars except I only get partial in-and-out reception (2-3 bars) on 11. I also noticed that I do pick up some stations with the antenna unhooked from just the coax ran from the attic.

Since this one antenna is doing the trick, I probably won't build another except for fun to maybe try and pick up some fringe stations in Baton Rouge and Mississippi. It would be nice to have an antenna I could just aim and point in case of another hurricane down here. I have built a 2nd iteration Koch fractal DB4 which seems to work pretty good but only in one direction (probably because of the DB4 build?). I think I would like to try a yagi or a log-periodic antenna with a fractal driven element to try and pick up more wavelengths. Not sure if that would work or not. Regardless, it would have to be outside and out of my attic to try and pick up anything that far away. I appreciate the help and advice from everyone. Thanks. :)

LordCy
 

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Regardless, it would have to be outside and out of my attic to try and pick up anything that far away.
No chance of takin this guy outside on the garage or main roof, just for a quick test, see what ya can get from the outside?
 

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lordcy said:
one is an old rabbit ears and UHF loop and the other is a fractal DB4 that I built. They are attached via a combiner to two tvs.
Does that mean 2 antennas connected simultaneously? At the same time?

If yes ... that could be problematic given all the powerful signals so nearby.

Yes, the two "antennas covering the same area" connected together in the attic can cause unpredictable results.

Even just that one combo "rabbit ears, uhf loop" ant. may combine to cause strange effects under such conditions. The VHF part, telescoping rods, of this antenna usually need adjustment on a per channel basis - for good results - even for bi-directional operation. But you can't adjust it - cause it's in the attic (?) (not near the TV)

Try this: Disconnect from all current antennas in attic, connect only to a separate, independent, UHF loop (8 inch circle and balun/matching transformer to your down cable).

[ No combiner, no other antennas, no telescoping rod antenna / dipoles / wabbit ears ]

Cause I think it's those "Wascully Wabbits" - causing your trouble.
 

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lordcy keep at it you will find the VHF hi reflectors and top hat that will work for you in 4NEC2 or you could go build the wildwille for channel 11 :eek:

xauto Just use a 6 foot coax cable with one end to the tv and the other on the floor should work.
oh i did that and placed a piece of tin foil 11 inches long by 3 inches widwe and pulled in all my stations i got before and vhf hi fox down here in chatham-kent lmao got to love the foil antenna cheep simple


lordcy ther are many ways to use your base elements you have constructed already to be used with top hats and a couple of VHF hi reflectors test you will see
 

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Discussion Starter #14
sorry for the long delay

I was unable to get that sucker onto the roof to test the distance until today (built on wood, it is kind of heavy). I was able to get all the local channels (in green) like I'm able to in my attic. When I pointed the antenna around 290 degrees outside (towards Baton Rouge) at about 12-13 feet on roof (I was holding it up there on a ladder by the gutter trying not to move it), I was able to see channel 33.1 which is about 81 miles away but it wasn't enough signal to watch the channel. I think if it was a tad bit higher and not swaying by me holding it or the wind I might have been able to pick it up. A reflector could also have helped. When I pointed it around 45 degrees (towards Mississippi) I wasn't able to receive any additional channels except the local ones. I think the roof might have been limiting me there. I'm thinking about building a new light weight GH0n and mounting it with a reflector about 25 feet in the air with some kind of manual rotor over the summer. If I do get around to it I'll let you all know the outcome. Thanks for everybody's help and comments. Much appreciated.

LordCy
 

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I'm thinking about building a new light weight GH0n and mounting it with a reflector about 25 feet in the air with some kind of manual rotor over the summer.
Adding a reflector on a GH0n defeats its purpose as a bi-directional antenna, and you need the bidirectionality.

In your situation, I would have the GH0n as my main antenna and build a high gain GH10n3 or even higher gain DBGH10n3 for the really weak distant stations, along with a quality preamp. You could then combine the two coax downleads into an A-B switch at the TV.
 
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