I'm putting up a tower in the next week or so. It will have a TA33.

I've been putting up antennas for years, but never with a tower. I know the
old adage that you should put up as much aluminum as you can afford as high
as you can put it. However, will there be a noticeable difference between
34' and 44'? I work DX and with the declining sunspots, I suspect that on
some weak signals it might.

Thanks

Dave - W5GT

Easy......

At One Wavelength the "spray" on the antenna opens fully........as you raise
the antenna the angle of take off lowers......(getting you to your DX
station with more apparent power).

-In W2PV's bible...the take off angle of a 3 element beam at 1 wl is 14
degrees, raise it to 1.5 WL and now the take off is 9 degrees...go to 2 WL
and its 7 degrees.

-Now take into consideration the useable angle of propagation, as the angle
rises you will begin to use the higher lobes of your antenna.

-There are times that because of the very high propagation angle my vertical
is stronger than my 5 ele @ 150' and my 4 element at 106' and my multibander
at 68'......

Bill
http://www.kc4pe.com/amateurshack.htm



"W5GT" wrote in message
...
I'm putting up a tower in the next week or so. It will have a TA33.

I've been putting up antennas for years, but never with a tower. I know
the
old adage that you should put up as much aluminum as you can afford as
high
as you can put it. However, will there be a noticeable difference between
34' and 44'? I work DX and with the declining sunspots, I suspect that on
some weak signals it might.

Thanks

Dave - W5GT

The center of the first lobe's elevation angle can be calculated by:

arcsin of (a/4*H), where a=1 and H = the antenna height in wavelengths.

Plugging in 34 and 44 feet respectively (after normalizing to wavelengths),
will show you how much improvement you are likely to see in reducing the
takeoff angle.

Keep in mind the TOA is a cone or lobe, not a line.

At 14.1 Mhz, a wavelength is approx 69 feet. So 34/69 is .49. The value of H
for 20m and 34 feet is .49. The formula then is arcsin of 1/(4*.49)....this
will give you the TOA (takeoff angle) for your horizontal antenna at 34'. Do
the same calculation for 44' and you will see the TOA is lower.

Do the calculation for each band you are interested in. Be sure to calculate
the wavelength for each band:

982/f, where f is in Megahertz.

BTW, the first null is found by using a=2, the 2nd lobe (if there is one)
will be found at a=3, the second null (if there is one) will be found at a=4

You will see these additional lobes and nulls on 10 meters, but not on 20m

Hope this helps. 73

....hasan, N0AN

p.s. Every little bit helps if you are a DX'er.


"W5GT" wrote in message
...
I'm putting up a tower in the next week or so. It will have a TA33.

I've been putting up antennas for years, but never with a tower. I know
the
old adage that you should put up as much aluminum as you can afford as
high
as you can put it. However, will there be a noticeable difference between
34' and 44'? I work DX and with the declining sunspots, I suspect that on
some weak signals it might.

Thanks

Dave - W5GT

That should have been 984/f, not 982...bad memory.

N0AN
"hasan schiers" wrote in message
...
The center of the first lobe's elevation angle can be calculated by:

arcsin of (a/4*H), where a=1 and H = the antenna height in wavelengths.

Plugging in 34 and 44 feet respectively (after normalizing to
wavelengths), will show you how much improvement you are likely to see in
reducing the takeoff angle.

Keep in mind the TOA is a cone or lobe, not a line.

At 14.1 Mhz, a wavelength is approx 69 feet. So 34/69 is .49. The value of
H for 20m and 34 feet is .49. The formula then is arcsin of
1/(4*.49)....this will give you the TOA (takeoff angle) for your
horizontal antenna at 34'. Do the same calculation for 44' and you will
see the TOA is lower.

Do the calculation for each band you are interested in. Be sure to
calculate the wavelength for each band:

982/f, where f is in Megahertz.

BTW, the first null is found by using a=2, the 2nd lobe (if there is one)
will be found at a=3, the second null (if there is one) will be found at
a=4

You will see these additional lobes and nulls on 10 meters, but not on 20m

Hope this helps. 73

...hasan, N0AN

p.s. Every little bit helps if you are a DX'er.


"W5GT" wrote in message
...
I'm putting up a tower in the next week or so. It will have a TA33.

I've been putting up antennas for years, but never with a tower. I know
the
old adage that you should put up as much aluminum as you can afford as
high
as you can put it. However, will there be a noticeable difference between
34' and 44'? I work DX and with the declining sunspots, I suspect that on
some weak signals it might.

Thanks

Dave - W5GT