Posted by
George Thornton on
Mar 14, 2020; 9:08am
URL: http://elecraft.85.s1.nabble.com/Off-Topic-Your-advice-suggestion-about-antenna-tp7658892p7658915.html
I would add the following comments.
You can easily reach the point of obsession with antennas, and some of the choices involve heavy expense, tons of room, tolerant neighbors and a lot of maintenance.
I think the Yagi antennas are among the best choices, by their nature they concentrate strength in one direction. As a horizontal polarized antenna they are less affected by noise than vertically polarized antennas. They also heavily concentrate power in one direction, and they naturally filter out interfering signals coming from the sides. They are fun and work really well.
I am a SteppIr fan and their antennas are well built and reliable. I have done wonders with a 3 element trombone version using just 100 watts in an urban location with the antenna mounted on a nine foot rooftop tower.
Yagis do involve heavy wind loading and they do require a sturdy tower type base of support and a substantial rotor.
Size is always better but with size also comes expense, hard work and maintenance. Looking at SteppIr, a three element Yagi is light enough to be raised by hand with a small crew of two or three people using a gin pole. The larger SteppIrs weigh around 250 lbs and you will need a boom truck.
There is a lot of wind loading with Yagis and wind storms can cause a lot of damage. Your rotor needs to be pretty sturdy; even the three elements need a Tailtwister or better. You have to go really heavy duty with the big boys and that costs a lot more money.
Our Mike and Key field day site sports a wide variety of Yagis. I run the GOTA station with a small three element trapped Yagi that I can support on a temporary tripod mount made out of Army surplus aluminum tubes. The 40 meter Yagi is made of wire, six elements with what looks like a 100 ft boom, erected on lines run between trees.
-----Original Message-----
From:
[hidden email] <
[hidden email]> On Behalf Of Rick Bates, NK7I
Sent: Friday, March 13, 2020 12:02 PM
To:
[hidden email]
Subject: Re: [Elecraft] Off-Topic: Your advice/suggestion about antenna
Duane,
I agree on both points. The antenna is THE most important element of any station (the accepted maxim is it's 90% of the budget but most hams are 'cheap'). The radio is useless without a decent antenna. An EDZ can work well but the peaks and nulls vary on every band and wind in the trees can be an issue. Height matters, a LOT too.
I also hid (in plain sight) a similar 370' EDZ (at 35') antenna IN the HOA space (shot a wire over some oak trees) for years without it being seen and it worked well (other than the noise floor was obscenely high, all the time because it was urban). It absolutely ROCKED on 40M (the noise precluded hearing much on 160M but I got 15-20 countries).
If budget is less of a concern, you might want to consider SteppIR, starting with the 2 element Urban beam (40-6M). The only other comment along that line is leave a LOT of headroom capacity when selecting a rotator, they take a lot of wind abuse. There are other beam antennas worth consideration, many are less expensive.
When I moved away from the HOA infestation area into rural with a 40 db
(average) lower noise floor, in time I went from all band (R7, dipole or
vertical) wires to a SteppIR DB36/80 (80-6M) which gave me an average of another 10 dB of GAIN in reception (plus directivity to null noise even further AND transmit gain too).
I bought the antenna, rotor and tower at an estate sale (SK sale), saving many thousands of dollars. The son (a non-ham) just wanted it all gone, I assisted ;-) so keep watch, ready to 'attack'.
The sole remaining wire is an Inverted L for 160M. I greatly prefer this to any dipole because the one wire is not pulled/stretched between multiple trees when it's windy (and the trees NEVER sway in sync at the same moments). It moves precisely WITH the tree motion, it isn't stretched or pulled. However, it's moderately deaf on 160M, I'll have to add an RX array (RBOG or 8 square are the current considerations) yet I'm now at 131 countries worked on 160M.
The sole sticking point remaining is my requirement that NOTHING antenna can be seen from the house (I bought an amazing view, it came with a house), so even with the acres I have, I'm limited to a few acres total, further reduced by proximity to the power lines along the road. Fortunately my neighbor (700' away) is also an HF active ham with even more acres (same visual rule) so we're considering a shared RX array (SDR and wifi based, which removes much of the desense issue too).
So my suggestion is that you look at the larger picture and perhaps even start fresh, not re-modify the original plans (make it a Revolution, not just an evolution). Part of my move (escape to) here was just for that reason, to start with a fresh station based on simplicity of operation (which takes a LOT of planning and work to obtain; in a couple years, it'll be there, I hope.)
GL,
Rick NK7I
On 3/13/2020 11:19 AM, Lyn Norstad wrote:
> Duane -
>
>
>
> I am of the mind that the antenna is the most crucial part of any
> station, and probably the most often maligned. I have made a number
> of presentations to ham groups on the design and construction process
> involved in getting the most bang for the buck, depending on your
> wants and needs (everybody's are different).
>
>
>
> In my own situation (2 acre semi-rural lot approx.150 feet x 600 feet
> running E-W feet, and active HOA) the goal was to have a single
> antenna that would provide the best primary signal on 80 meters in a
> North-South direction, while providing the best possible signal on 40
> meters in an East-West direction, consistent with the 80 meter
> performance and without unduly provoking the HOA (or my XYL).
>
>
>
> I decided on an Extended Double Zepp, cut for 3.5 MHz. That resulted
> in a length of 360 feet, which worked nicely since I have 400 feet
> clear from the house (West end) to a perfect tree for the far East
> end. And another tree in the center for support of both the antenna and the feedline.
>
>
>
> I am feeding it with a 160 foot length of 600 ohm "true ladder line."
> I can go into more detail if this sounds like something that would
> work. Modeling this antenna with EZ NEC shows a maximum theoretical
> gain of 4.7 dbi in both North and South directions. With the ladder
> line, a dual hybrid balun and short length of coax into the shack, my
> KAT500 tunes it very nicely on all bands 160 m thru 6m.
>
>
>
> I don't have your call so can't see where you are, but would be happy
> to make other suggestions based on the coverage you seek.
>
>
>
> 73
>
> Lyn, W0LEN
>
>
>
>
>
> -----Original Message-----
> From:
[hidden email] [mailto:
[hidden email]]
> Sent: Friday, March 13, 2020 11:52 AM
> To: Lyn Norstad;
[hidden email]
> Subject: Re: [Elecraft] Off-Topic: Your advice/suggestion about
> antenna
>
>
>
> Hi Lyn - thanks for the reply!
>
> I have 3 acres of wooded land.
>
> Its pretty much on two different levels.
>
> The house is located on the lower level.
>
> And from there the grade goes upwards about 30 feet- and then levels
> off to the second level.
>
>
>
> Many elm trees which can support an antenna height of about 45 feet.
>
> And I can cut through a path through them if necessary.
>
>
>
> I have a 40m moxon pointed towards Asia at 45 feet hanging over solid
> rock
>
> I've made a few DX contacts with it during the years when propagation
> was peaking.
>
> But right now I think its really to low to the ground to be useful.
>
>
>
> I'm interested in what you have in mind.
>
> Thanks
>
> Duane
>
>
>
> On Fri, Mar 13, 2020, at 12:31 PM, Lyn Norstad wrote:
>
>> Duane -
>> There are other wire antenna options that will far outperform a
>> simple dipole, or for that matter a 2EL yagi.
>> How much space do you have available?
>> 73
>> Lyn, W0LEN
>> -----Original Message-----
>> From:
[hidden email]
>> [mailto:
[hidden email]] On Behalf Of
>>
[hidden email]
>> Sent: Friday, March 13, 2020 10:38 AM
>> To:
[hidden email]
>> Subject: [Elecraft] Off-Topic: Your advice/suggestion about antenna
>> From what I understand - solid rock below a raised vertical is not
>> the
> best
>
>> option for performance.
>> With an underlying geography of many feet of solid metamorphic rock -
>> that would probably rule out the low angle benefits of vertical antennas.
>> Consequently, over the years, every 40m vertical I've ever put up has
>> been out-performed by a dipole at .41 wavelength. I've also tried
>> the DX-Half Square and vertical Delta Loop with the same results.
>> It looks to me like my only option to outperform a 40m dipole - is a
>> tower and (at minimum) a 2EL yagi.
>> Would that assumption be correct?
>> Thanks
>> Duane
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