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eHam Forums => Elmers => Topic started by: KE6TDT on November 22, 2012, 02:41:52 PM



Title: Get higher angle of radiation with a vertical?
Post by: KE6TDT 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!



Title: RE: Get higher angle of radiation with a vertical?
Post by: WB6BYU 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.


Title: RE: Get higher angle of radiation with a vertical?
Post by: KE6TDT 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.


Title: RE: Get higher angle of radiation with a vertical?
Post by: WB6BYU 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.


Title: RE: Get higher angle of radiation with a vertical?
Post by: KH6AQ on November 22, 2012, 04:44:01 PM
You can obtain some high angle radiation by using one radial per band.


Title: RE: Get higher angle of radiation with a vertical?
Post by: KE6TDT on November 22, 2012, 05:07:30 PM
Thanks for that Dale. I will take that into consideration.


Title: RE: Get higher angle of radiation with a vertical?
Post by: KE6TDT 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.



Title: RE: Get higher angle of radiation with a vertical?
Post by: K0ZN 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


Title: RE: Get higher angle of radiation with a vertical?
Post by: K9YLI 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..


Title: RE: Get higher angle of radiation with a vertical?
Post by: WB2WIK 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.


Title: RE: Get higher angle of radiation with a vertical?
Post by: KE6TDT 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.   


Title: RE: Get higher angle of radiation with a vertical?
Post by: KE3WD 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. 



Title: RE: Get higher angle of radiation with a vertical?
Post by: K1WJ 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


Title: RE: Get higher angle of radiation with a vertical?
Post by: WB6BYU 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.


Title: RE: Get higher angle of radiation with a vertical?
Post by: KE6TDT 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.


Title: RE: Get higher angle of radiation with a vertical?
Post by: WB6BYU on November 28, 2012, 08:19:16 AM
Height above ground isn't the important factor for such high angles.

The problem is that you have a vertical radiator, and any such linear element
will have a null off the end.  That null points straight up, and regardless of the
length of the element or the height above ground, it will always have a null
overhead.  If you make it long enough (in wavelengths) then you can get
more radiation at angles closer to the end of the wire, but that isn't practical
for 40m and 80m.

With a single radial you add a horizontal radiator that will help to fill in the
null.  A horizontal dipole or inverted vee is even better because more of the
antenna is horizontal.  But by itself a vertical conductor isn't going to radiate
at high angles, no matter what you do to it.


Title: RE: Get higher angle of radiation with a vertical?
Post by: K6SCA on November 28, 2012, 09:45:45 AM
For what KE6TDT is wanting to accomplish I'm a little surprise no one has suggested he try a dipole in NVIS configuration. While it may not be a vertical, it would fill the bill for the distance he's looking for.


Title: RE: Get higher angle of radiation with a vertical?
Post by: KE3WD on November 28, 2012, 10:25:30 AM
For what KE6TDT is wanting to accomplish I'm a little surprise no one has suggested he try a dipole in NVIS configuration. While it may not be a vertical, it would fill the bill for the distance he's looking for.


Because we recommended the Inverted Vee config, which is really a dipole, but the Vee will usually raise the radiation angle over the flat dipole's. 

There also will be a change in pattern lobes that can help out, especially when crossbanding with a tuner. 


73


Title: RE: Get higher angle of radiation with a vertical?
Post by: KE6TDT on November 29, 2012, 09:42:37 PM
Thanks for all contributions/suggestions here.

Trying to absorb the seemingly endless antenna configurations and details  which can obviously be somewhat time consuming and complicated to those of us without formal educations or substantial experience in this field. 

To be honest after reading the manufacturer HF Wire/Vertical antenna reviews an all the boasts and claims, I will likely build my own inverted V.  hihi...

I actually built and used one simple insulated 18 gage inverted V a few years ago, fed with 300 ohm twin lead, (yes, TV type) no balun, using Radio Shack foam cored 20 gauge,  300 ohm feedline- part #15-1175, with each leg being 61 feet, a total of 122'. It was only about 26' above the ground on a roof mounted aluminum mast strapped to a chimney.  Operated only 100 watts, with a non-pro 746 and first contact was Tasmania from S. CA., on twin lead.... I think it was 20meters.  What a kick.   No balun and was fed straight into the balanced wire connections of a basic inexpensive MFJ 949D tuner.   

I have the HF6Vx which I've owned and used for well over 20 years, but is currently disassembled on it's side, not in use. I'll get it back up one day.  I took everything down, and I am now nearly antenna-less. 

In fact I'm listening to 75 meters right now hooked up to a mobile mag mounted 2 meter whip inside the home, fed to an old Kenwood R-1000.  Still have to work to eat, so unfortunately I have not a lot of time to devote to research etc. Sometimes I get a mental block trying to visualize what people are describing regarding antennas, and find I need to read things 2 or 3 times and it still doesn't sink in fully. Then I read it a 4th time...lol 

But it's all fun. Thanks all. 



Title: RE: Get higher angle of radiation with a vertical?
Post by: WB6BYU on November 30, 2012, 09:47:56 AM
For working 75m around the Southwest, a simple dipole or inverted vee is
a good choice.  You can use it on 40m also by adding a second element
for 40m to the same feedpoint (if using coax feed) or by feeding it with
twinlead to a tuner in the shack.

You can get more elaborate than that, but it won't improve your
performance much.

Height above ground will help to improve your signal at longer distances,
but getting sufficient height may be impractical on 75m.


Title: RE: Get higher angle of radiation with a vertical?
Post by: KB5UBI on December 03, 2012, 02:01:57 PM
I have two doublets and a ground mounted Butternut HF6V for 75 meters. At my QTH, (night time) the vertical seems to be my best 75 meter antenna for 100 miles plus. Inside 100 miles, it's a toss-up between the vertical and a doublet. Close in, I would think a horizontal full wave loop would be in order.


Title: RE: Get higher angle of radiation with a vertical?
Post by: W5DXP on December 04, 2012, 04:42:55 AM
Trying to absorb the seemingly endless antenna configurations and details  which can obviously be somewhat time consuming and complicated to those of us without formal educations or substantial experience in this field.

Don't know if anyone else has suggested it, but turning a 1/4WL ground-mounted vertical into a 3/4WL inverted-L will raise the Take-Off-Angle from 26 degrees to 89 degrees turning the vertical into an NVIS antenna.