Scantenna directivity

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dgoodson

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...yes, I have searched the forum for this.

I recall reading somewhere, I think in one of these forums, that the scanntenna is considered omnidirectional, but IF you installed it on a metallic mast, it would take on some directional characteristic.

My Scantenna (actually the old Channel Master's version) is mounted on an aluminum mast with the antenna boom pointed north.

Its just pure, idle curiosity: is there any truth to the directivity claim, and if so, can anyone speculate as to what the enhanced direction is?
 
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fuzzymoto

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I have a similar setup (ST-2 on a mast) and I seem to receive equally well in every direction. This is of course hard to quantify in any way but if there is a directional characteristic going on my guess would be that it is minimal.
 

DavidNVA

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Mine is certainly directional. Have it facing one way and I can hear Dulles ATIS and clearance delivery have it facing another direction and no more ATIS or clearance delivery.

I do not however have it mounted on a mast (HOA Rules), it's setup with a preamp in a spare bedroom upstairs (will go into the attic once I get out of this neck brace - trampolines are evil! :) ) So that very well could have something to do with it.

Works very well for me w/ the air bands, but I'd have better results using yarn as an antenna when it comes to the 800mhz trunks in the area. I use a mag mount cell phone antenna for those.
 

dgoodson

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Mine is oriented with the boom pointing north, so the mast is on the south side of the antenna. Compared to a plain ole 1/4 ground plane at the same location (which this antenna replaced), Signals from the North and West are significantly improved, from the East it really doesn't seem remarkably better. There isn't anything to speak of South of me, so I don't have any sense of that.
 

sony

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dgoodson said:
...yes, I have searched the forum for this.

I recall reading somewhere, I think in one of these forums, that the scanntenna is considered omnidirectional, but IF you installed it on a metallic mast, it would take on some directional characteristic.

My Scantenna (actually the old Channel Master's version) is mounted on an aluminum mast with the antenna boom pointed north.

Its just pure, idle curiosity: is there any truth to the directivity claim, and if so, can anyone speculate as to what the enhanced direction is?
I have had the Channel Master antenna before and now I just installed the Scantenna and just the construction and quality of the parts the Channel Master is better made in quality and it is a larger antenna with longer elements.

I would like the answer to the above question also as I just installed mine and couldn't figure which way to point it but not for signal but for the best wind protection knowing which way the wind blows I don't know if turning the antenna one way or another is going to make a difference as the last 2 channel masters I lost the top element on the same day but the mounts were unaffected. The antennas broke.
 

fuzzymoto

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I had some limitations with my roof in how I mounted mine that limited my orientation. Mine is aimed SSW with the mast behind (or to the north) of the antenna. I get a ton of wind, most (not all) from the west or south west but my orientation was not based on that. I suspect eventually I'll take a tree branch hit and have to replace it but so far so good. Mine has been fine in the heavy winds I get up here.
 

sony

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fuzzymoto said:
I had some limitations with my roof in how I mounted mine that limited my orientation. Mine is aimed SSW with the mast behind (or to the north) of the antenna. I get a ton of wind, most (not all) from the west or south west but my orientation was not based on that. I suspect eventually I'll take a tree branch hit and have to replace it but so far so good. Mine has been fine in the heavy winds I get up here.
Yes it also depends on your limitations if you have things that might be in the way of antenna in which way to point it and type of mount. It is an all direction antenna. I would be more concerned as to what is the best way to position antenna depending on the direction of where your wind usually comes from.
 

kb2vxa

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Hi guys,

Cutting right to the chase the Scantenna being a dipole does exhibit a slight cardioid pattern on some frequencies when obstructed by metal and this includes the coax. The only way to eliminate pattern distortion is mounting on a non metallic mast and run the coax horizontally. Being impractical you'll just have to put up with a minor null in the shadow of the mast.

"I would be more concerned as to what is the best way to position antenna depending on the direction of where your wind usually comes from."

I really don't see the significance of wind direction except where the bits land when they blow off, it's not exactly a rugged antenna.
 

sony

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The performance is good on Scantenna we will have to see how it does in the wind with that fiberglass modification.
 
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fuzzymoto

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So far I'm going on about 7 months with mine in action. I get a LOT of wind where I sit and It's been fine so far. As I mentioned I'm sure it is in more danger of a branch hit than pure wind damage but we'll see.

My Scantenna doesn;t seem to look the same as yours =}
 

sony

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fuzzymoto said:
So far I'm going on about 7 months with mine in action. I get a LOT of wind where I sit and It's been fine so far. As I mentioned I'm sure it is in more danger of a branch hit than pure wind damage but we'll see.

My Scantenna doesn;t seem to look the same as yours =}
Well during the last week I installed two of them to replace the 2 Channel Masters I had up there since 1994? The mounts endured the strong winds it was the antenna elements the vertical top pieces that went first. When I removed the Channel Masters I could see that the top V element was the next element to fail due to many wind storms it was an accumulation and repeated wind storms not just one windstorm that did this.
I was thinking should I turn the antennas the opposite of the way I had them before as I know the direction of the wind here is North-South so I position the Scantennas where the two V's one top and one bottom are not facing the wind to get caught like a parachute but have them facing the wind like an airplane wing would in hopes the wind will just go through. But whether it makes a difference or not I still have the fiberglass reinforcement taped on and the UV ties both on for reinforcement for the main element.
Does this reinforce the whole antenna? or just the vertical element?
 

fuzzymoto

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sony said:
Well during the last week I installed two of them to replace the 2 Channel Masters I had up there since 1994? The mounts endured the strong winds it was the antenna elements the vertical top pieces that went first. When I removed the Channel Masters I could see that the top V element was the next element to fail due to many wind storms it was an accumulation and repeated wind storms not just one windstorm that did this.
I was thinking should I turn the antennas the opposite of the way I had them before as I know the direction of the wind here is North-South so I position the Scantennas where the two V's one top and one bottom are not facing the wind to get caught like a parachute but have them facing the wind like an airplane wing would in hopes the wind will just go through. But whether it makes a difference or not I still have the fiberglass reinforcement taped on and the UV ties both on for reinforcement for the main element.
Does this reinforce the whole antenna? or just the vertical element?
Just the vertical element, although it does tie the vertical better to the main horizontal shaft too.
Mine was cheap. If it breaks I'll buy another.
 

sony

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fuzzymoto said:
Just the vertical element, although it does tie the vertical better to the main horizontal shaft too.
Mine was cheap. If it breaks I'll buy another.
But another Scantenna for $49.95
Those other elements that are V shaped on top and bottom is there anyway to stregthen those?
On my Channel master I saw that it started to break away at the top V element after I lost top vertical element.
 

fuzzymoto

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I think I paid $35 for my ST-2 and that was including the 50-foot cable I didn't need.

I'm sure there is a way to strengthen anything you'd like but at some point the weight may become more of a problem than benefit. Ten or twenty rolls of UV safe tape and you'd have a Scatenna mummy that woul resist almost anything. I live way up on a cliff with constant wind and every so often some serious winds. So far so good. I wouldn't knock yourself out too much trying to make it bullet-proof.
 

sony

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fuzzymoto said:
I think I paid $35 for my ST-2 and that was including the 50-foot cable I didn't need.

I'm sure there is a way to strengthen anything you'd like but at some point the weight may become more of a problem than benefit. Ten or twenty rolls of UV safe tape and you'd have a Scatenna mummy that woul resist almost anything. I live way up on a cliff with constant wind and every so often some serious winds. So far so good. I wouldn't knock yourself out too much trying to make it bullet-proof.
Well that's taking it to the limit especially if it is a hassle to mount and dismount antenna. I did put coax seal on one of the antennas between vertical element and V to keep those elements from moving.
Where can you get the ST-2 for $35.00? Also is this version (ST-2) a better wind resistant antenna to the original? IF so how is it more wind resistant?
 

Dubbin

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sony

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fuzzymoto said:
Its gone up a little since I bought it:

http://cgi.ebay.com/Heavy-Duty-Scan...ryZ40980QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

eBay / antenna warehouse

Mine was pretty easy to put up so it's not too much of a limit. I certainly don't want it to fail or have to replace it but I'm not going to lose sleep over how to reinforce it any better than I can reasonably do.
I live in a very windy area and have been checking the two antennas so far so good and I did do that reinforcement as described except using both UV black ties and black electrical tape. I paid $49.95 for the Scantenna. Will see if these hold up for 10 years or so like the other channel masters I had.
 

kb2vxa

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Hi again,

"Ten or twenty rolls of UV safe tape and you'd have a Scatenna mummy that woul resist almost anything."

Fuzzy, you really crack me up! After THAT one I no longer think of you as Fmoto but rather fuzzy logic.

Here at the Jersey Shore we get violent thunderstorms in summer and are famous for our winter gales, no way in hell would I consider a Scantenna. If you're so concerned with wind damage why bother with something known not to survive and go with something that WILL?

Another one that cracked me up was the one about turning into the wind, are you piloting a sail boat? Tacking is for sailors, not for antennas, wind blows as it will and you can't tell it what to do. Then what makes you think it matters? The elements will blow off no matter which way the wind hits them and it gets worse when those vees vibrate like stop signs in a hurricane, the whole idea just blows.

The bottom line is the antenna is a piece of crap and there's no getting away from poor mechanical construction. Well, that is unless you mummify it. (;->)

"I prefer to do it the old way off-line make a phone call with credit card and talk to a live person."

Yeah, in INDIA. Stop it guys, I'm gonna bust something I'm laughing so hard. STOP! Doggone it, STOP.... dammit, somebody call an ambulance.
 
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