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Author Topic: Get higher angle of radiation with a vertical?  (Read 4368 times)
KE6TDT
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Posts: 73




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« on: November 22, 2012, 02:41:52 PM »

Considering putting up HF6V,  which would be roof mounted with the base about 23' with the radial kit. Is there anyway or tricks to obtain a higher angle of radiation for more local 500 mile traffic?  I know the HF6V Butternut is more than DX capable, but was interested if there was a way to trick or push the antenna into producing a higher angle of radiation, like a wire?

Thanks!

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WB6BYU
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« Reply #1 on: November 22, 2012, 02:49:36 PM »

Mount the antenna horizontally.

Or, since you are going to use a set of radial wires running across the roof, use
two of them going in opposite directions as a dipole.
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KE6TDT
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« Reply #2 on: November 22, 2012, 02:51:50 PM »

Ya, I thought of that, but my question is in regards to obtaining possibly higher radiation angles in a vertical configuration.
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WB6BYU
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« Reply #3 on: November 22, 2012, 03:39:39 PM »

You could do that by making the antenna taller:  a 3/4 wave vertical has maximum
radiation at about 45 degrees, and should work fairly well for propagation in the
200 to 500 mile range.  But  that would be 180 feet tall on 80m, which isn't
practical for most ham installations.  Or perhaps 90' on 40m, but that is still
far taller than most rooftop installations, and the ionosphere won't support
propagation at high angles on higher frequency bands.

So basically, the answer is "No" if you are talking about a vertical radiator with
a symmetric radial system, because effectively the direction of desired radiation
is off the end of the wire where there is a null in the pattern.  The only way
you are going to manage it is to get some horizontally polarized radiation, and
the only horizontal radiators you have in your system will be your radial wires.

So if you connect just 1 quarter wave radial wire you make a bent dipole, and
the radial wire will contribute a significant component overhead.  This comes
with some further issues about preventing common mode currents on the coax
shield, which can mess up the pattern, but it is possible.  (In some cases,
reports of vertical antennas working well for shorter skip distances may be
due to radiation from the coax shield.)

A better approach is my second original suggestion:  with two quarter wave
radial wires running in opposite directions, you can feed them like a dipole
for high angle radiation and switch them to serve as radials on the vertical
for low angle radiation.  A DPDT relay can probably be pressed into service
at the feedpoint to allow remote switching between the two modes on a
single length of coax.
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WX7G
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« Reply #4 on: November 22, 2012, 04:44:01 PM »

You can obtain some high angle radiation by using one radial per band.
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KE6TDT
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Posts: 73




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« Reply #5 on: November 22, 2012, 05:07:30 PM »

Thanks for that Dale. I will take that into consideration.
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KE6TDT
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Posts: 73




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« Reply #6 on: November 22, 2012, 05:10:01 PM »

You can obtain some high angle radiation by using one radial per band.

Thanks Dave. I'll read up on doing what you suggested.

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K0ZN
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« Reply #7 on: November 22, 2012, 08:40:51 PM »


WX7G is correct.  If you use ONE radial per band, basically, what you have is a bent dipole on each band.  I would recommend a balun or isolation choke at the feed point if you
do that to minimize RF from flowing on the out side of the coax.  To wit: the "vertical" is one half of a dipole and the single radial wire would be the other. Radiation angle should be considerably higher angle with that set up at 25 ft.  I suspect you may run into some elevated, but not "bad", SWR since the system is kind of unbalanced.....but it will radiate fine.   A tuner probably would make life a lot easier with that set up.

73,  K0ZN
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K9YLI
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« Reply #8 on: November 23, 2012, 07:16:57 AM »

depending on the direction  you want to  communicate, and you live in   Calif.
just moount the antenna on a 10 to 15 degree angle to the  south west.
adjust as needed to  get the range you want.  that would be aimed at most of the  US.

Radiation pattern is a doughnut  around the verticle..  tilt the doughnut..
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WB2WIK
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« Reply #9 on: November 23, 2012, 08:16:43 AM »

Unless I missed it, I think the important question wasn't asked:

What band are you looking to use to work the 500-mile stuff?

With the HF6V on 75/80m, you'd be very lucky to work 500 miles daytime and probably never will.  At night, the HF6V is a good choice for 500 miles on that band.

On 20 meters, you're at the mercy of propagation and no matter what your antenna radiation angle is, if the ionosphere won't support 500 mile propagation because that's all in the first skip zone (for everyone in your area at the time), you can make all sorts of changes and it still won't work.
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KE6TDT
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« Reply #10 on: November 26, 2012, 06:39:16 PM »

Unless I missed it, I think the important question wasn't asked:

What band are you looking to use to work the 500-mile stuff?

With the HF6V on 75/80m, you'd be very lucky to work 500 miles daytime and probably never will.  At night, the HF6V is a good choice for 500 miles on that band.

On 20 meters, you're at the mercy of propagation and no matter what your antenna radiation angle is, if the ionosphere won't support 500 mile propagation because that's all in the first skip zone (for everyone in your area at the time), you can make all sorts of changes and it still won't work.

Thanks Steve,

I understand the propagation regarding daylight 75/80 and 20 meters etc.

75 meters is a band I enjoy tuning around since I'm in the southwestern U.S., I would like to hear/talk to Northern CA, Arizona, Utah, Oregon, Colorado, Washington etc.  So you feel the HF6Vx would work well for the 200 to 900 mile traffic on 75 in the evening hours? 

BTW, since posting this I have also considered instead installing an inverted V at about 40 feet. Would you estimate the HF6V would transmit/receive as reasonably well at those ranges as the inverted wire V? 

My concerns with the HF6Vx were electrical noise and transmit signal going over the regions mentioned above.   
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KE3WD
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« Reply #11 on: November 27, 2012, 06:25:45 AM »

...BTW, since posting this I have also considered instead installing an inverted V at about 40 feet. Would you estimate the HF6V would transmit/receive as reasonably well at those ranges as the inverted wire V? ...   

That sounds to me like a very good idea, having been there and done that at one point in time. 

My Vertical was ground mounted with as many radials as I could install underneath it, made from all sorts of various surplus wire, both insulated and a few bare as well.  Kept adding more radials and soldering them to the 10AWG copper wire ring placed at the bottom of the vertical, this over almost a decade in time when I lived at that QTH. 

Inverted Vee was hung from a lanyard and pulley, as one would raise a flag on a flagpole, this allowed me a wee bit of experimentation as to the height of the center of the vee from about 60' at top to anywhere below that point. 

From that QTH, I found that 35-40' was about ideal for stateside work, not only the ragchew, but doing net on 40.  *MANY* times the SA net went like this:  I'd hear someone trying to call the net control and finally would break back in:  "KE3WD with the relay..."   -  because the net control was using a Vertical in Chicago.  My Inverted Vee in Pittsburgh heard almost everybody stateside.  Coupled with about 600W of linear when needed, the thing served well. 

That Inverted Vee started life as a homebrew G5RV, btw, then converted to balanced line fed vee.  Both performed well for the intended purpose, with the balanced line fed inverted vee slightly outperforming the G5RV.  Was using one of the old Heathkit large antenna tuners with both. 

And invest in a good Antenna Switch as well. 

Being able to switch between the two available antennas rapidly (the vertical was tuned to the CW portions of the bands so I would use the antenna tuner to use it on sideband portion) turned out to be very useful. 

Every once in a while, that "low-hanging" inverted vee would yield a better received signal from DX stations, most reporting a bit more received signal on their end from my transmission as well.  Go figure. 

And that vertical worked the world CW with a small amount of SSB occasionally as well, contesting the worldwides also proved the system. 

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K1WJ
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« Reply #12 on: November 27, 2012, 09:49:47 AM »

For 75m I used an inverted-v - Total length 119ft - apex at 35ft - ends at 12ft. Kicked ass in 100-500m range. 73 K1WJ
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WB6BYU
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« Reply #13 on: November 27, 2012, 12:43:06 PM »

The inverted vee likely will outperform the vertical out as far as
Sacramento or Phoenix. 

For Portland or Denver it will depend on your ground conditions and
the height and orientation of the inverted vee - you'll have to try
it and see.
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KE6TDT
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Posts: 73




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« Reply #14 on: November 27, 2012, 06:38:16 PM »

Regarding the roof mounted elevated HF6Vx, at what height, or is there a height which would favor a bit more local work, such as the 100 to 500 mile range. I thought I'd read about 14' at the base would favor this, as opposed to say 20' feet high at the base of the vertical.

I should have added, I am unable to have a ground mounted vertical at this venue. Only roof mounted.
« Last Edit: November 27, 2012, 06:49:49 PM by KE6TDT » Logged
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