Re: Topband: Low band antenna project questions

[Richard (Rick) Karlquist]

On 3/7/2016 3:11 PM, Jim Brown wrote:
The vertical

pattern of any antenna is produced by the reinforcement of the direct
wave by the first reflection from the earth. That reflection is MUCH
stronger, and is strong at a lower angle, if the "earth" at the point of
reflection is sea water. Sea water will NOT improve signal strength in
directions where the first reflection is over land.

73, Jim K9YC


Not quite.  The reinforcement of vertically polarized waves
from a perfect ground plane is 3 dB.  For a real ground,
the worst that can happen is that you lose the whole 3 dB
and get down to the free space value ... as long as you are talking
about angles above the pseudo-Brewster angle.  For angles below
the pseudo-Brewster angle, the reflection amplitude is the same
for both a perfect ground and a lousy ground.  The difference
is that for lousy ground the PHASE of the reflection is inverted.
This results in near perfect cancellation at low angles.
As we all know, this effect is much greater than 3 dB.

For a ground mounted vertical, I don't think the idea of
doing ray tracing to see if the "point of reflection" is
over sea water is very useful, because the vertical does
not model as a source at a definable height, AFAIK.  It's
probably more like the wave has to be over salt water not
just at a point of reflection, but continuously from the antenna
out to some critical radius.  In this region, it is still
a ground wave.  Possibly, this radius corresponds to the
point where the ray has reached a critical height
such that the wave has been "launched" and can be
considered to be a skywave.  I don't know if this critical
height is a function of take off angle or ground conductivity.
For example, if the take off angle is 30 degrees, and
the critical height is a half-wavelength, the critical
radius (in terms of wavelength) is half of the square
root of 3 (0.866...).  This is just trig.  I don't
claim these are the actual numbers.

If there really were a single "point of reflection", then
I could put some half wave reflector wires on the ground
a long distance from the antenna and generate a huge
signal at a particular low angle.  If this worked,
I suspect it would have been discovered long ago
and exploited.

The over the horizon radar people may have figured this
out.  They use huge ground screens to actually try to
simulate the vertical on the beach paradigm.

Rick N6RK
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Re: Topband: Low band antenna project questions

[Jim Brown]

On Mon,3/7/2016 12:37 PM, NC3Z Gary wrote:

My 160M dipole is actually a 160/80M fan and resonates well on both
bands,


For several years after I moved to W6 ten years ago, I had a loaded 160 
dipole that was also resonant on 80M up at about 120 ft. Even at that 
height, its a low dipole on 160M, and 90% of the time, my 85 ft Tee 
vertical beat it, often by a lot.  When it had to come down for repair 
several years ago I removed the 160M loading coils and extension wires.



I did not think I could do that with a T top. That would solve
issues.

Would a cage of vertical wires be better than if I could use 2.5 to 1.5"
aluminum masting?


Anything that would increase the height of the vertical section would 
improve radiation efficiency a bit, but wide spaced wires would make the 
tuning broader.



Luckily in our rural local club we have 2 hams that sell some neat
products, one is the Air-boss launcher


A guy in the SF Bay area developed the compressed air tennis ball 
launcher that I've seen at least ten years ago. It's very slick, works 
quite well. K2RD brought his over to my QTH soon after I moved here, and 
with his first shot, cleared the tallest redwood on my property by at 
least 10 ft. That tree is about 200 ft tall.

and the other is the Antenna Tensioner.


That looks very good for trees of moderate size, but I'd like something 
a bit more robust for the tall ones we have out here. :)


73, Jim K9YC

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Topband: Low band antenna project questions

[Bill N6MW]

For 160/80 some features under discussion and used, both at home and for 
V7, were a 55' vertical + drooping T (2x or 3x wires at ~ 45 degrees but 
reachable from the ground for initial tuning) + two/few experimentally 
tuned elevated radials for each band. The raw antenna is long on 80 and 
matched by a series cap (air with enough gap for power). It is short on 
160 and can be matched by a hairpin coil across the input. Of course, 
you must somehow switch between the cap and the coil to change bands -- 
not completely trivial. In my case, this done by hand at the base amid 
the dark/rain/snakes. Especially on 80 this antenna is significantly 
off-center-fed and required substantial extra coax coiled up as a choke. 
The story is written up on my website. This method probably has limits 
on 80 if using just a field of 160 m ground radials, although adding a 
couple of elevated tuned 80m radials might do the trick - or so says 
standard EZNEC. EZNEC also hints that you might also be able to have a 
mix of 160 m and 80 m radials to get a similar effect but the limits of 
EZNEC when radial ground effects may be important are well known.


This antenna had acceptable (second-tier in pile ups) performance on 
160m using 700 watts and was quite good on 80. The V7 version with 2 
drooping T wires and 2 elevated radials for each band was just okay on 
160 but good on 80, probably limited by trees proximity and restricted 
geometry, although some might claim enhanced by being on a beach with 
adjacent ocean.


Bill N6MW

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Re: Topband: Low band antenna project questions

[NC3Z Gary]

OK, this has me intrigued. So the T top would look like this if looking 
straight up (or straight down) with the vertical portion at the xx?

x
x
x
xx
xx
xx
xx
  x  x
   xx
  x  x
xx
xx
xx
xx
x
x
x

My 160M dipole is actually a 160/80M fan and resonates well on both 
bands, I did not think I could do that with a T top. That would solve 
issues.

Would a cage of vertical wires be better than if I could use 2.5 to 1.5" 
aluminum masting?

Luckily in our rural local club we have 2 hams that sell some neat 
products, one is the Air-boss launcher and the other is the Antenna 
Tensioner. The tensioner has proven its self here in the eastern NC 
winds. And being a boating area I have several West Marine stores nearby.


Gary Mitchelson
NC3Z/4 Pamlico County, NC FM15

On 07-Mar-16 12:48, Jim Brown wrote:
> Hi Gary,
>
> The antenna you describe should work quite well on both bands, but I'll
> suggest a couple of tweaks to make the matching easier. First, make it a
> Tee -- if you have a catenary, you can support a Tee as easily as an L.
> Second, make the top section a fan (like a fan dipole) with short
> elements to resonate it on 80 and longer ones for 160. Third, don't
> worry about remoting the tuner unless you feedline is very long. Unless
> the match is really bad, feedline loss on 80 and 160 is pretty low,
> especially if you use RG8. Also, you can make the tuning more broadband
> (and electrically lengthen the vertical section by 1-2 percent) by using
> two parallel runs spaced 12-18 inches, tied together top and bottom. Do
> a simple NEC model to get dimensions.
>
> Finally, use as many radials as you can, don't worry a lot about length,
> just think more is better. :)  BTW -- 50 ft on the ground will be close
> to a quarter wave on 80, 100 ft on 160.
>
> As to physical details -- get a good pulley at each end, tie one end
> down, put a weight on the other end, and use some sort of "mechanical
> fuse" at the feedpoint so that wind doesn't break it. I use a mating
> pair of Pomona connectors -- when the wind blows, they simply un-mate.
> For the fan spreaders, cut short lengths (12-18 inches is great) of
> 1/2-in PVC conduit, drill holes about 3/4-in from each end to pass the
> wires through.  Make this antenna as physically robust as possible to
> withstand the wind. At a minimum, #10 THHN for the long top sections
> that carry the stress. #12 or #14 is fine for the shorter top sections.
> Don't make any soldered connections -- they don't weather well, and wire
> tends to break at a soldered joint. Instead, use split-bolt copper clamp
> connectors sized to fit the wire you're using. For support rope, use
> 5/16-in rope from http://www.synthetictextilesinc.com/supportham.html
> It's resold by lots of ham vendors, but Synthetic Textiles is a bit
> cheaper. Smaller rope is sufficient for strength, but you'll appreciate
> the larger size when you're trying to pull on it to maximize tension,
> which pulls it higher. :)  Don't use hardware store pulleys -- instead,
> use marine pulleys (good) or this excellent "rescue" pulley, which is
> also easy to rig.
>
> http://www.ropescoursewarehouse.com/catalog1/advancedwebpage.aspx?cg=1851=4=202=SKU=1250=914=CKfCobGOr8sCFQWUfgod5DUOHQ
>
>
> Out here in CA, the West Marine is the place to buy marine pulleys.
>
> 73, Jim K9YC
>
> On Mon,3/7/2016 5:50 AM, NC3Z Gary wrote:
>> Now I want to be able to use this antenna for 80M as well as the non-DX
>> portion of 160M. I can house a autotuner at the base (or make my own
>> network but that would require control lines). My thinking is to make
>> the 160M a 5/16 WL vs 1/4 to be more beneficial to 80M tuning without
>> loosing anything on 160M.
>
> _
> Topband Reflector Archives - http://www.contesting.com/_topband
> .
>
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Re: Topband: Low band antenna project questions

[Grant Saviers]

Good recommendations.  I did a couple of things differently for my 160 T 
hung to 3 trees,


I use Lewmar or Ronstan or Harken small swivel blocks, cheaper, more 
durable in tough environments and the swivel helps keep lines from 
tangling or twist from messing things up.  Don't use 3 strand rope. 
Whichever I can find cheapest in 30mm or so.

http://www.mauriprosailing.com/us/product/LEW29925001BK.html?gclid=CLC7qJefr8sCFYRrfgodbeYH_Q
http://www.fisheriessupply.com/lewmar-30mm-synchro-control-blocks

For any serious load the ball bearing blocks are terrific.  I loop my 
hoist line thru the block to the tie off (or weight or bungee), so if 
the antenna wire breaks, I still have a line through the pulley.  I use 
a separate line over the tree branch for the pulley and after a while 
the tree grows around it and it won't come down. The wind oscillation 
should be in the antenna hoist line, not the pulley line to minimize 
chafe.  Let the block sheave do the moving. With a loop the hoist line 
can be replaced with a new one with a careful splice/tape to go thru the 
block.  1/4"  braid dacron from Synthetic is awesome and plenty strong 
enough, and ok on the hands with gloves to what I can pull (100# +).


For the top T wire, I use Davis RF 13ga copperweld stranded with the 
poly cover, no stretch, less weight, high strength, and less corrosion

http://www.davisrf.com/antenna-wire/polystealth.php

I always use a bowline knot and Scotch 33 tape the bitter end after 
another half hitch.  It's a great knot but I've seen them shake out 
under cyclic loads.


I use a 50::25 ohm TLT which is a very good match for my antenna, easy, 
broad band and zilch loss.  My  T  is tuned low in the band and then use 
series caps to cover the band to 1980 or so.


Grant KZ1W

On 3/7/2016 9:48 AM, Jim Brown wrote:

Hi Gary,

The antenna you describe should work quite well on both bands, but 
I'll suggest a couple of tweaks to make the matching easier. First, 
make it a Tee -- if you have a catenary, you can support a Tee as 
easily as an L.  Second, make the top section a fan (like a fan 
dipole) with short elements to resonate it on 80 and longer ones for 
160. Third, don't worry about remoting the tuner unless you feedline 
is very long. Unless the match is really bad, feedline loss on 80 and 
160 is pretty low, especially if you use RG8. Also, you can make the 
tuning more broadband (and electrically lengthen the vertical section 
by 1-2 percent) by using two parallel runs spaced 12-18 inches, tied 
together top and bottom. Do a simple NEC model to get dimensions.


Finally, use as many radials as you can, don't worry a lot about 
length, just think more is better. :)  BTW -- 50 ft on the ground will 
be close to a quarter wave on 80, 100 ft on 160.


As to physical details -- get a good pulley at each end, tie one end 
down, put a weight on the other end, and use some sort of "mechanical 
fuse" at the feedpoint so that wind doesn't break it. I use a mating 
pair of Pomona connectors -- when the wind blows, they simply 
un-mate.  For the fan spreaders, cut short lengths (12-18 inches is 
great) of 1/2-in PVC conduit, drill holes about 3/4-in from each end 
to pass the wires through.  Make this antenna as physically robust as 
possible to withstand the wind. At a minimum, #10 THHN for the long 
top sections that carry the stress. #12 or #14 is fine for the shorter 
top sections. Don't make any soldered connections -- they don't 
weather well, and wire tends to break at a soldered joint. Instead, 
use split-bolt copper clamp connectors sized to fit the wire you're 
using. For support rope, use 5/16-in rope from 
http://www.synthetictextilesinc.com/supportham.html  It's resold by 
lots of ham vendors, but Synthetic Textiles is a bit cheaper. Smaller 
rope is sufficient for strength, but you'll appreciate the larger size 
when you're trying to pull on it to maximize tension, which pulls it 
higher. :)  Don't use hardware store pulleys -- instead, use marine 
pulleys (good) or this excellent "rescue" pulley, which is also easy 
to rig.


http://www.ropescoursewarehouse.com/catalog1/advancedwebpage.aspx?cg=1851=4=202=SKU=1250=914=CKfCobGOr8sCFQWUfgod5DUOHQ 



Out here in CA, the West Marine is the place to buy marine pulleys.

73, Jim K9YC

On Mon,3/7/2016 5:50 AM, NC3Z Gary wrote:

Now I want to be able to use this antenna for 80M as well as the non-DX
portion of 160M. I can house a autotuner at the base (or make my own
network but that would require control lines). My thinking is to make
the 160M a 5/16 WL vs 1/4 to be more beneficial to 80M tuning without
loosing anything on 160M.


_
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Re: Topband: Low band antenna project questions

[Richard (Rick) Karlquist]

On 3/7/2016 11:05 AM, John Pescatore via Topband wrote:

It is resonant on 160, with about 16 radials out now,

 so don't need a tuner there. I've tried it on other bands
 with a tuner in the shack, and performance is horrible.

Could have been so much loss in the coax that a base

of the antenna tuner might change things but I wouldn't
 want that to be my only HF antenna.


73 John K3TN


If it is series resonant on 160, it is likely to be
approximately parallel resonant on 80 and 40, with
a very high drive impedance.  This severe mismatch
will give you a lot of loss in the coax, even though
it might be low loss when matched.  A tuner at
the base of the antenna will solve this problem and
you should have excellent results.  The tuner,
however, will have to be one that can match an
impedance in many 100's or maybe 1000's of ohms.
Not just any tuner.

Rick N6RK
_
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Re: Topband: Low band antenna project questions

[Gary Smith]

Gary,

Though our conditions are different, I also have a top height of 
somewhere around 50-60'. I don't know exactly, I run a sloper over 
the top of the tallest tree I can find from my radial plate. I'm at 
the edge of a marsh and every hurricane takes down trees and I need 
to get them up over what is left. The only tuner I have is in the k3 
and I pretty much use that only to make the radio happy with the 
input of the amplifier. Half my radials are on the marsh and the 
other 1/2 are in the woods.

Unlike your situation, I have a lot of excessively long radials about 
130' each. I also have a 350' run of coax to the remote switchbox. I 
have the 129' long 160M sloper, an 80M Inv-L, 40M vert wire, 30M Vert 
wire and a butternut in the middle of the radial plate that I use for 
20 only. Right before the radial plate is the distal end of an 
Ameritron RC5-8V coax switch.

I don't need any tuner to have a good match on all of the HF bands 
with this:

160M = Sloper
80M = 80M vert
40M = 40M vert
30M = 30M vert
20M - Butternut
17M = 80M vert
15M = 40M vert
12M = 80M vert & 160 Sloper
10M = 160M Sloper

You've gotten some great advice on specifically what to do from 
others, I am including this less specific info to try to demonstrate 
how it's worth experimenting with the info you've been given and you 
will surely find something that works well with your 50' height 
limit.

73,

Gary
KA1J


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Topband Reflector Archives - http://www.contesting.com/_topband

Topband: 160M vertical on sloping land

[N2TK, Tony]

At KP2M we have a FCP inv-L for 160M. This has improved our signal from the
sloping dipole we originally had up. The land has a steep downward slope
towards the north, about 45 degrees. The vertical is about 30’ above an
elevated feed about 10’ above the ground. The L portion goes up the hill to
a tower.

>From the vertical, EU is about 45 degrees and the USA is about 345 degrees.
The vertical is about 140’ above sea level and about ½ mile or so from the
ocean.

 

This island is all rock. It is the only island in the Leewards that Is not
volcanic in origin.

 

Thinking about replacing the two legs of the FCP with radials. Can only have
lengths about 35’ or so.  The thought was to either lay them on the ground
or elevate them. Probably will need to add a coil between the joining of the
radials and the coax shield. Figure on adding some ferrite cores and wrap
several turns of coax through it at the feedpoint. Was thinking about using
4-6 radials since they are so short and fanning them from the west to the
east. Was not planning on radials behind the vertical towards the south as
there is a very high hill directly behind the house to the south.

 

Has anyone done any modeling of something like this and/or had experience
with our dilemma?

 

Tnx for any feedback

73,

N2TK/NP2, Tony

 

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Re: Topband: Low band antenna project questions

[John Pescatore via Topband]

Gary - I've had a 51' T up for 6 or 7 years now and it is a very good transmit 
antenna on 160. It is resonant on 160, with about 16 radials out now, so don't 
need a tuner there. I've tried it on other bands with a tuner in the shack, and 
performance is horrible. On most bands, it heard/talked worse than a mutliband 
vertical I had up for a while and is many dB below my 135' OCF dipole at the 
same height on every band other than 160. I think I modeled it once using one 
of the online programs and you can see a very spiky pattern.

Could have been so much loss in the coax that a base of the antenna tuner might 
change things but I wouldn't want that to be my only HF antenna.

73 John K3TN
_
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Re: Topband: Low band antenna project questions

[Jim Brown]

Hi Gary,

The antenna you describe should work quite well on both bands, but I'll 
suggest a couple of tweaks to make the matching easier. First, make it a 
Tee -- if you have a catenary, you can support a Tee as easily as an L.  
Second, make the top section a fan (like a fan dipole) with short 
elements to resonate it on 80 and longer ones for 160. Third, don't 
worry about remoting the tuner unless you feedline is very long. Unless 
the match is really bad, feedline loss on 80 and 160 is pretty low, 
especially if you use RG8. Also, you can make the tuning more broadband 
(and electrically lengthen the vertical section by 1-2 percent) by using 
two parallel runs spaced 12-18 inches, tied together top and bottom. Do 
a simple NEC model to get dimensions.


Finally, use as many radials as you can, don't worry a lot about length, 
just think more is better. :)  BTW -- 50 ft on the ground will be close 
to a quarter wave on 80, 100 ft on 160.


As to physical details -- get a good pulley at each end, tie one end 
down, put a weight on the other end, and use some sort of "mechanical 
fuse" at the feedpoint so that wind doesn't break it. I use a mating 
pair of Pomona connectors -- when the wind blows, they simply un-mate.  
For the fan spreaders, cut short lengths (12-18 inches is great) of 
1/2-in PVC conduit, drill holes about 3/4-in from each end to pass the 
wires through.  Make this antenna as physically robust as possible to 
withstand the wind. At a minimum, #10 THHN for the long top sections 
that carry the stress. #12 or #14 is fine for the shorter top sections. 
Don't make any soldered connections -- they don't weather well, and wire 
tends to break at a soldered joint. Instead, use split-bolt copper clamp 
connectors sized to fit the wire you're using. For support rope, use 
5/16-in rope from http://www.synthetictextilesinc.com/supportham.html  
It's resold by lots of ham vendors, but Synthetic Textiles is a bit 
cheaper. Smaller rope is sufficient for strength, but you'll appreciate 
the larger size when you're trying to pull on it to maximize tension, 
which pulls it higher. :)  Don't use hardware store pulleys -- instead, 
use marine pulleys (good) or this excellent "rescue" pulley, which is 
also easy to rig.


http://www.ropescoursewarehouse.com/catalog1/advancedwebpage.aspx?cg=1851=4=202=SKU=1250=914=CKfCobGOr8sCFQWUfgod5DUOHQ

Out here in CA, the West Marine is the place to buy marine pulleys.

73, Jim K9YC

On Mon,3/7/2016 5:50 AM, NC3Z Gary wrote:

Now I want to be able to use this antenna for 80M as well as the non-DX
portion of 160M. I can house a autotuner at the base (or make my own
network but that would require control lines). My thinking is to make
the 160M a 5/16 WL vs 1/4 to be more beneficial to 80M tuning without
loosing anything on 160M.


_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Low band antenna project questions

[Charles Moizeau]

Gary,

Given the 50' maximum height of a presumably level catenary line supported at 
its ends, there are two things you can do to significantly improve the 
performance of the 50' vertical wire hanging below.

1.  Obtain a stout piece of bamboo.  Try to make at least a 10' long pole, and 
this may require using two bamboo pieces butted together.   Make two rope 
bridles.  Attach the ends of both to opposite ends of the bamboo pole.  Make 
sure that the length of each bridle is such that when both are pulled taut from 
each bridle's center, a square pattern is formed.  Using a goodly quantity of 
light-weight wire (#26 stranded copper that has a modest coating of pvc 
insulation is a suggestion), make yourself a reasonably dense top-hat by 
running lengths of the chosen wire out in rays, with each ray extending to the 
perimeter of the rope bordered square that you've formed.  Then run the same 
gauge of wire around the square perimeter of the rope square.  Using lead-free 
solder (recommended is 96% Sn, 4% Ag), solder all the rays together at their 
center, together with the top end of your vertical antenna wire, and each 
junction of the ray ends to the perimeter wire.  Use GE's pure silicone
  black caulk, daubing some on every soldered joint.  All this work can be 
easily done at ground level, after having first driven in a couple of ground 
stakes at the center of each rope bridle to keep the bridles taut in their 
intended square configuration.  Break your catenary line at the point where you 
want your vertical wire to hang.  Attach each inner end of the catenary line to 
the center of each bridle rope.  Elevate!

2.  Use a much shorter bamboo pole and appropriately shorter rope bridles.  
Attach a self-supporting length of light-weight aluminum tubing to the center 
of the pole and connect that to the top of your vertical antenna wire.  Fasten 
the bridles to the split catenary rope as in no. 1.

My preference is for no. 1.  This because the taller a vertical antenna, the 
more it needs longer radials to harvest radiation splashed off the ground for 
recycling back to the antenna's feedpoint.  Because you are limited in the 
length of your radials, a shorter capacitance top-loaded vertical will play 
better than a >50' tall vertical.

Have a look in the QST archives for the picture of Jerry Sevick's eight-foot 
tall 40-meter vertical wearing a very large top hat.

73,

Charles, W2SH 

> From: n...@outlook.com
> To: topband@contesting.com
> Date: Mon, 7 Mar 2016 15:28:08 +
> Subject: Re: Topband: Low band antenna project questions
> 
> That is the highest I can get support for. I am in far eastern NC and 
> right on the sound where we get hurricanes and nor'easters so I am not 
> putting up the towers I had at the old QTH.
> 
> 
> Gary Mitchelson
> NC3Z/4 Pamlico County, NC FM15
> 
> On 07-Mar-16 09:49, Robert Harmon wrote:
> > Gary,
> > Are you restricted to 50 feet high max ?
> >
> > Bob
> > K6UJ
> >
> > On 3/7/16 5:50 AM, NC3Z Gary wrote:
> >> OK, still working on my permanent low band antenna and what I can fit
> >> for an effective antenna. The space I have is a recently cleared forest
> >> area. I had originally considered a full size loop but the best I could
> >> do is 50' high, although that would be a bit higher than my temporary
> >> dipole it is not much in the scheme of things. And I keep getting talked
> >> out of it.
> >>
> _
> Topband Reflector Archives - http://www.contesting.com/_topband

  
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Re: Topband: Low band antenna project questions

[NC3Z Gary]

That is the highest I can get support for. I am in far eastern NC and 
right on the sound where we get hurricanes and nor'easters so I am not 
putting up the towers I had at the old QTH.


Gary Mitchelson
NC3Z/4 Pamlico County, NC FM15

On 07-Mar-16 09:49, Robert Harmon wrote:
> Gary,
> Are you restricted to 50 feet high max ?
>
> Bob
> K6UJ
>
> On 3/7/16 5:50 AM, NC3Z Gary wrote:
>> OK, still working on my permanent low band antenna and what I can fit
>> for an effective antenna. The space I have is a recently cleared forest
>> area. I had originally considered a full size loop but the best I could
>> do is 50' high, although that would be a bit higher than my temporary
>> dipole it is not much in the scheme of things. And I keep getting talked
>> out of it.
>>
_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Low band antenna project questions

[Robert Harmon]

Gary,
Are you restricted to 50 feet high max ?

Bob
K6UJ

On 3/7/16 5:50 AM, NC3Z Gary wrote:

OK, still working on my permanent low band antenna and what I can fit
for an effective antenna. The space I have is a recently cleared forest
area. I had originally considered a full size loop but the best I could
do is 50' high, although that would be a bit higher than my temporary
dipole it is not much in the scheme of things. And I keep getting talked
out of it.

I have walked the back many times with the tape measure and lines to see
what I can fit, and what I can fit is a catenary line to support a T or
L at 50' above ground. And after reading numerous articles the consensus
was not to use radials much longer than the vertical height. I can
easily fit 32 radials @ up to 75' each.

Now I want to be able to use this antenna for 80M as well as the non-DX
portion of 160M. I can house a autotuner at the base (or make my own
network but that would require control lines). My thinking is to make
the 160M a 5/16 WL vs 1/4 to be more beneficial to 80M tuning without
loosing anything on 160M.

With the above limitations is this an effective solution?
T or L ?
Am I missing anything?

Working on a RX antenna later.



_
Topband Reflector Archives - http://www.contesting.com/_topband

Re: Topband: Low band antenna project questions

[mstangelo]

Gary,

I have an inverted L similar to this setup and it does a decent job on 160 
through 20 meters.

I put up an inverted L supported in trees because it fit he backyard layout. It 
is 5/16 long with a 50-55 foot vertical component.

I have 30 radials 70 feet long and 4 130 foot radials because this is what it 
into the yard. 

I only run 100 watts and use an MFJ-929 autotuner. 

I first started out with a 160 meter dipole at 50 feet and this inverted L 
performs much better.

I use one set of halyards for the supports over the trees and a second set of 
pulleys to support the L.  The L support lines have wood stump counterweights 
to allow for sway. I can easily lower the inverted L to prepare for a major 
storm.

Good luck with the installation.

Mike N2MS


- Original Message -
From: NC3Z Gary 
To: topband@contesting.com
Sent: Mon, 07 Mar 2016 13:50:29 - (UTC)
Subject: Topband: Low band antenna project questions

OK, still working on my permanent low band antenna and what I can fit 
for an effective antenna. The space I have is a recently cleared forest 
area. I had originally considered a full size loop but the best I could 
do is 50' high, although that would be a bit higher than my temporary 
dipole it is not much in the scheme of things. And I keep getting talked 
out of it.

I have walked the back many times with the tape measure and lines to see 
what I can fit, and what I can fit is a catenary line to support a T or 
L at 50' above ground. And after reading numerous articles the consensus 
was not to use radials much longer than the vertical height. I can 
easily fit 32 radials @ up to 75' each.

Now I want to be able to use this antenna for 80M as well as the non-DX 
portion of 160M. I can house a autotuner at the base (or make my own 
network but that would require control lines). My thinking is to make 
the 160M a 5/16 WL vs 1/4 to be more beneficial to 80M tuning without 
loosing anything on 160M.

With the above limitations is this an effective solution?
T or L ?
Am I missing anything?

Working on a RX antenna later.

-- 

Gary Mitchelson
NC3Z/4 Pamlico County, NC FM15
_


_
Topband Reflector Archives - http://www.contesting.com/_topband

Topband: Low band antenna project questions

[NC3Z Gary]

OK, still working on my permanent low band antenna and what I can fit 
for an effective antenna. The space I have is a recently cleared forest 
area. I had originally considered a full size loop but the best I could 
do is 50' high, although that would be a bit higher than my temporary 
dipole it is not much in the scheme of things. And I keep getting talked 
out of it.

I have walked the back many times with the tape measure and lines to see 
what I can fit, and what I can fit is a catenary line to support a T or 
L at 50' above ground. And after reading numerous articles the consensus 
was not to use radials much longer than the vertical height. I can 
easily fit 32 radials @ up to 75' each.

Now I want to be able to use this antenna for 80M as well as the non-DX 
portion of 160M. I can house a autotuner at the base (or make my own 
network but that would require control lines). My thinking is to make 
the 160M a 5/16 WL vs 1/4 to be more beneficial to 80M tuning without 
loosing anything on 160M.

With the above limitations is this an effective solution?
T or L ?
Am I missing anything?

Working on a RX antenna later.

-- 

Gary Mitchelson
NC3Z/4 Pamlico County, NC FM15
_
Topband Reflector Archives - http://www.contesting.com/_topband