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what do you guys make of this antenna?
- Thread starter bob85
- Start date
No clue. Is the coil made of stainless steel?
And while I'm at it, I'd like to quote the ARRL Antenna Handbook (16th Edition):
And while I'm at it, I'd like to quote the ARRL Antenna Handbook (16th Edition):
I've always wondered why the Spectrum 1600 and your antenna run 6 or more radials.
no chief its all aluminum exept the two insulators in the radiator, i will try to describe it as i remember it from the early 80's,
the radiator is fed much like any other antenna with an insulated radiator (the tapped small coil in the pic) , the lower 8 0r 9 foot of radiator consist of the center mast and 3 electrically connected legs that come away from the centre mast at an angle then back towards the mast connecting back to the lower mast just under the upper coil/insulator ( larger coil in pic ), above the upper coil is another 22 foot or so of radiator, the groundplanes are 6 full size 1/4 waves
i had it mounted at 68 then 73 foot to groundplanes, performance was superb but it would have been a much better antenna had it been made from larger tubing with a faster taper to stop it flexing so much in the wind,
just wondering if you guys can see any merrit to its design or figure out how it worked electrically
the radiator is fed much like any other antenna with an insulated radiator (the tapped small coil in the pic) , the lower 8 0r 9 foot of radiator consist of the center mast and 3 electrically connected legs that come away from the centre mast at an angle then back towards the mast connecting back to the lower mast just under the upper coil/insulator ( larger coil in pic ), above the upper coil is another 22 foot or so of radiator, the groundplanes are 6 full size 1/4 waves
i had it mounted at 68 then 73 foot to groundplanes, performance was superb but it would have been a much better antenna had it been made from larger tubing with a faster taper to stop it flexing so much in the wind,
just wondering if you guys can see any merrit to its design or figure out how it worked electrically
Bob, in the bottom coil is that an adjustable or fixed capacitor inside of the coil that is black in the picture. Maybe you can increase the length of the radiator a bit at this point to add or minus reactance? I don't see any hardware that allows one to adjust the length of the radiator. Maybe you could explain how it is tuned?
Are the three vertical wires in the vertical setup above the bottom coil set in those black square looking hubs insulating the wires from the radiator.
And it looks like the top coil is just for loading in order to raise the current distribution higher up the radiator. I figure this is probably a 1/4 type tape coil tuner that feeds a extended length 1/2 wave radiator and may be referred to as a 5/8 wave antenna. Maybe the three wires in the two square blocks on the radiator are inductively fed and just help push the current up to the loading coil above. Otherwise they look like extra hardware to me. This one is pretty similar to Coily's new GP antenna except for the three wires and the loading coil at the top.
Are the three vertical wires in the vertical setup above the bottom coil set in those black square looking hubs insulating the wires from the radiator.
And it looks like the top coil is just for loading in order to raise the current distribution higher up the radiator. I figure this is probably a 1/4 type tape coil tuner that feeds a extended length 1/2 wave radiator and may be referred to as a 5/8 wave antenna. Maybe the three wires in the two square blocks on the radiator are inductively fed and just help push the current up to the loading coil above. Otherwise they look like extra hardware to me. This one is pretty similar to Coily's new GP antenna except for the three wires and the loading coil at the top.
hello marconi, the bottom black part is just an insulator doing the same thing as the fiberglass rod in the i10k, the 3 legs are connected to the center radiator at both ends and the length of the lower radiator is fixed, the only means of tuning are altering the 21/22 foot section above the upper coil and a small adjustment range on the tapping point of the lower coil.
Ok Bob, one more time. You note:
And the one about the bottom insulator I understand.
Describe in some detail how those GP radials were attached and what were they made of?
The name of this one was the Big Mac, made by who and from where? And did you tell us how long it was overall, also how long was the thing from coil to coil?
I assume the coax screwed into the base of the coil support below the tap point, and maybe that base was able to move a bit around the mast to change the tap point some and find 50 ohms resistive, right.
Good report on a strange one to this side of the world, I think.
I see the three legs connected, but does that mean they are insulated from the radiator or that they are electrically connected? That was my question.
And the one about the bottom insulator I understand.
Describe in some detail how those GP radials were attached and what were they made of?
The name of this one was the Big Mac, made by who and from where? And did you tell us how long it was overall, also how long was the thing from coil to coil?
I assume the coax screwed into the base of the coil support below the tap point, and maybe that base was able to move a bit around the mast to change the tap point some and find 50 ohms resistive, right.
Good report on a strange one to this side of the world, I think.
the antenna was made by ham international in europe, the radials are 1/4wave aluminum and mounted in a cast aluminum boss that is connected to the lower end of the bottom coil and mounting stub like a regular 5/8gp antenna, the lower mast and legs are electrically connected together and i would say 8 to 9 feet fixed length between coils with another 21/22 feet above the top coil, overall length from groundplane to tip was 31 to 32 feet, whole antenna is dc grounded and the tapping point could only be moved a small distance each way. hope this makes things clearer.
Everything understood, but the three wires. You are saying these three wires deals are about 9' long (between coils) and you call them legs, right?
It looks to me like these three wires are imbedded in those insulator, or are they metal bosses like you mentioned about the ground plane bracket below. Can't tell if those dark block looking jobbers are insulators or not.
The wires being electrically connected together inside of those black brackets is one thing and they could also be electrically connected to each other, but are they electrically connected to the radiator also?
It looks to me like these three wires are imbedded in those insulator, or are they metal bosses like you mentioned about the ground plane bracket below. Can't tell if those dark block looking jobbers are insulators or not.
The wires being electrically connected together inside of those black brackets is one thing and they could also be electrically connected to each other, but are they electrically connected to the radiator also?