20m Yagi height
 

How high does a 20 meter yaga need to be. will 50 feet be enough or do I
need 70?

Any recomendations on a foldover tower that I will not have to climb so I
can service tha antenna and rotor?


73

W4WEG

Bill Grimwood wrote:
How high does a 20 meter yaga need to be. will 50 feet be enough or do I
need 70?

Depends upon what areas you want to cover. I prefer 30 ft because
I get a large "localized" beamwidth. Here's what EZNEC sez about
the 5 element 20m Yagi that is included in the EZNEC package.

Height Gain Take-off-angle Vertical Beamwidth
30' 13 dBi 25 deg 30 deg
50' 14.5 dBi 18 deg 20 deg
70' 15 dBi 13 deg 14 deg

Decide who you want to talk to and take your pick.
--
73, Cecil, W5DXP

I have my tribander at about 40 feet. There have been times, when I had my
amp on, that European stations told me I had the loudest signal coming in
from the States. I attribute that to the fact that the big guns with their
100 foot towers were shooting over Europe into central Asia. For extreme
long haul, like China, the 40 feet seems to be really the best on 15 meters
..

My tower is an old Wilson TT45. There is a modern US Tower equivalent, but
they call it 40 foot; depends on how tall a mast you stick on the end. You
can't use a thrust bearing with these, but the price is right. So, you put
any large antenna a couple of inches above the rotator. They come standard
with a tiltover base and house bracket. Mine is bracketed to the back of the
garage, and folds over parallel to the wall. This takes some exact
measurements to get the base in the right place. Also, when you fold it
down, the tower has to move slighty away from the wall, not into it. In my
case, 90 degrees was not an option, but would be the preferred way to do it.
Tam/WB2TT
"Bill Grimwood" wrote in message
...
How high does a 20 meter yaga need to be. will 50 feet be enough or do I
need 70?

Any recomendations on a foldover tower that I will not have to climb so I
can service tha antenna and rotor?


73

W4WEG

Depends on what you want to do on 20, Bill. "Normal" 20M ops can get away
with 50-70 ft.; DXers usually demand 70 ft. minimum. Now, here's the
kicker: it's not 70 ft. above the earth; it's 70 ft. above *ground
reflection*. Where's your water table? How about local rooftops, and other
ground clutter? Aw, heck, just put it up 100 ft., and you won't have to
worry about it!!

73,
Mike KI6PR
El Rancho R.F.,CA

"Bill Grimwood" wrote in message
...
How high does a 20 meter yaga need to be. will 50 feet be enough or do I
need 70?

Any recomendations on a foldover tower that I will not have to climb so I
can service tha antenna and rotor?


73

W4WEG

The really big DXers have more than 1 beam on the tower and they feed them
stacked or singly to favorer the distance wish to work.
I have a height limit here of 40' and my antenna works OK, 271 confirmed,
but I wish it could be another 10' higher. I think it would work a bit
better. Remember if SWR and SWR bandwidth is important to you, then height
above ground is important. Check and see if the antenna your using specifies
a minimum height, mine did.


--
John Passaneau, W3JXP
Penn State University


"Mikey" wrote in message
...
Depends on what you want to do on 20, Bill. "Normal" 20M ops can get away
with 50-70 ft.; DXers usually demand 70 ft. minimum. Now, here's the
kicker: it's not 70 ft. above the earth; it's 70 ft. above *ground
reflection*. Where's your water table? How about local rooftops, and
other
ground clutter? Aw, heck, just put it up 100 ft., and you won't have to
worry about it!!

73,
Mike KI6PR
El Rancho R.F.,CA

"Bill Grimwood" wrote in message
...
How high does a 20 meter yaga need to be. will 50 feet be enough or do
I
need 70?

Any recomendations on a foldover tower that I will not have to climb so
I
can service tha antenna and rotor?


73

W4WEG

Back when I was a Novice, I wandered the neighborhood, looking at some of
the local hams' towers. I asked one of them, "I notice most of the guys
have 50' towers. Is that some sort of magic number?". His reply was,
"Actually, that's about as much tower as most of us can afford to buy!".

The bottom line is that you do what you can...it'll work, to some degree or
another.
73,
Mike KI6PR
El Rancho R.F., CA

"John Passaneau wrote
The really big DXers have more than 1 beam on the tower and they feed them
stacked or singly to favorer the distance wish to work.
I have a height limit here of 40' and my antenna works OK, 271 confirmed,
but I wish it could be another 10' higher. I think it would work a bit
better. Remember if SWR and SWR bandwidth is important to you, then height
above ground is important. Check and see if the antenna your using
specifies
a minimum height, mine did.