[GCARC] Where should KC2IEB put HF wire antennas?

Sun Nov 8 16:00:26 EST 2020

Chris,

Adding length in this way ( or any way you can ) would get it closer to
resonance on 40 meters which would normally require 66 feet of wire for a
half wave antenna.  Antennas which are too short have large amounts of
capacitive reactance, and will require a lot of inductive reactance to get
them to tune. It is almost always easier and more efficient to tune an
antenna which is too long, which is why for a doublet you would typically
make it long enough to tune the lowest band that you wish to operate, and
then use your tuner to make it "shorter" on the higher bands.

Based on my experience, I would say that the dipole will outperform the
end-fed in most cases, and a loop may or may not outperform the dipole at
an equivalent height.  Most loops that work really well are mounted fairly
high, the same as most dipoles that work really well. Any horizontal
antenna that is less than a half wavelength above the ground will radiate a
fair amount of power straight up, which is not great for long DX, but you
will still make plenty of contacts.  My low dipole on 80 meters works well
into Europe, but I am not working Asia with it very often, even with a
kilowatt.

Go ahead and try the AH-4 with the loop.  It may work very well.  And yes,
at the antenna is the most efficient place to put the tuner, but those of
us who live on tiny lots rarely run enough coax to have to worry about
losses of that nature.  Glad to see you are having fun experimenting with
antennas.  It is one of my most favorite aspects of the hobby, and I have
been enjoying it as a fun activity since I was 11 year old ( and I still
have a lot to learn ).

Tony K3TS

On Sun, Nov 8, 2020 at 10:01 AM Christopher Wawak <chris at wawak.org> wrote:

> The ends of the dipole are at about 30', I'd say. Adding length in this
> way wouldn't improve performance (get-out-ability), but would make it seem
> electrically longer and easier to tune?
>
> Re: the AH-4, apparently "he AH-4 is a wide-range antenna tuner capable
> of matching a 50 ohm feed line to an antenna feed impedance in the range of
> 10 to 5,000 ohms." That should be enough for a loop. I read somewhere that
> getting the antenna tuner closer to the antenna would reduce feedline
> losses. Does that seem to jive with your understanding?
>
> Good news! I made my first SSB DX on 17m today using a simple dipole cut
> for 30m. 55 into Slovenia on 100 watts. I then made a bunch of domestic SSB
> contacts on 17m where I was 59 every time - texas, colorado, amazing. Guess
> it's better than the end fed. :)  I seem to be getting very good audio
> reports too compared to what I'd expect from seeing how my signal gets out
> in FT8. Can't wait to see what the loop will bring!
>
> On Fri, Nov 6, 2020 at 7:51 PM Tony Starr <tstarr1450 at gmail.com> wrote:
>
>> Chris,
>>
>> OK, that's a good start.  How high are the ends of the dipole off the
>> ground?  You can make the dipole longer by hanging a wire off each end with
>> a small weight or tied to a ground stake.  8 feet of wire on each end of
>> that 50 foot dipole will easily tune up on 40 meters.
>>
>> I am not sure if that AH-4 will have enough tuning range, but it may.  I
>> am just not familiar with it.  I have not done much with loops, but like
>> any other antenna, they work well if you can get them up high enough, and
>> not as well down near the ground.  I still say if you can get the feed
>> point of the dipole up over the house, you could use the entire depth of
>> your lot, even diagonally like I did.  You might be surprised how long of a
>> dipole you can fit this way.
>>
>> Tony K3TS
>>
>> On Fri, Nov 6, 2020 at 5:48 PM Christopher Wawak <chris at wawak.org> wrote:
>>
>>> So - first, thanks for the advice.  I put up the longest dipole I could
>>> going from my deck back to the edge of my property and ... at roughly 50'
>>> long, it's a fine 30m dipole. Juuust missed 40. I’d guess it’s 25-30 feet
>>> up. SWR is higher than 3 under 30m, but never over 5 if the analyzer is to
>>> be trusted. If I tell the 7300 to go into "emergency tuner mode", I can
>>> tune and get out with no weirdness in the radio (temperature increase,
>>> voltage weirdness, explosion).
>>>
>>> My plan for tomorrow morning is to set up the ICOM AH-4 tuner I picked
>>> up a long time ago, and see if tuning closer to the antenna makes a
>>> difference.
>>>
>>> I can't tell yet if the end fed or dipole is getting out better, I'll
>>> keep everyone posted!
>>>
>>> Is it possible zigzag the dipole, maybe between the tree in the center
>>> of the yard? What about trying to make some sort of loop instead? I think
>>> can get a lot more wire up with a loop!
>>>
>>> On Thu, Nov 5, 2020 at 5:05 PM Tony Starr <tstarr1450 at gmail.com> wrote:
>>>
>>>> Chris,
>>>>
>>>> An end fed wire is good for backpacking and other light portable
>>>> operation, but the best wire antennas for fixed station use are the
>>>> center-fed dipole types, and there are many variations of those. Some of
>>>> these will work on all or most of the HF bands, such as the G5RV or ZS6BKW
>>>> style of doublets. With a good tuner, any doublet style antenna that is cut
>>>> for the longest band that you plan to operate will likely tune up on all or
>>>> most of the bands that are higher than that. In your case, a 90 foot wire
>>>> (45 each side of center) will tune up well on 60 meters, and should work
>>>> well enough on the bands above that in frequency. The two keys to this
>>>> approach are feeding the antenna with ladder line and using a tuner with a
>>>> balun and enough matching range to get you close to 50 ohms. I wrote a
>>>> comprehensive article on antenna tuners some time back that was published
>>>> in Crosstalk, but you can find it easily on our club website under The
>>>> Elmer's Shack section, along with lots of other useful articles of interest
>>>> to the newer operator.
>>>>
>>>> As far as how to fit a wire antenna to your lot, I will share with you
>>>> how I fit a full size 80 meter dipole on my 80 x 115 foot lot. We are
>>>> talking about an antenna that is 130 feet long. It runs diagonally from
>>>> from to back, which is the only way it would fit. One high support in the
>>>> center is all that is needed. Mine happens to be a tower, but a telescopic
>>>> pole, roof tripod, or tree branch will work just as well. The rear support
>>>> is a 2x4 that is lashed to a fencepost in the far corner of the back yard,
>>>> and the front support is a utility pole located near the curb on the
>>>> opposite corner of the property. A length of 1/8 dacron line tied to the
>>>> pole supports that end. It is tied high enough to be out of reach, but well
>>>> below any electric wires. The center feed line, which happens to be RG-8x
>>>> coax in my case, comes straight down and goes through the wall into the
>>>> shack.  I actually have a second dipole, cut for 40 meters, attached to the
>>>> same feed point. With the wires arranged at right angles, there is no
>>>> interaction between bands. This antenna also works well on 15 meters, as a
>>>> bonus. A few years ago, I made a 40/20 meter version of this antenna for
>>>> Field Day, when I was operating a solo effort. It also worked well on 15m.
>>>>
>>>> Always remember this, there is no one antenna that does it all, and
>>>> does it well. With a little luck, and some research, you should be able to
>>>> put up an antenna that works better than the last one, but not quite as
>>>> well as the next one. As you learn more about antennas, you should be able
>>>> to figure out what that "next one" might be. In the meantime, if you have a
>>>> question, just ask. There are a number of us in the club who will likely
>>>> know the answer from prior experience.
>>>>
>>>> Tony K3TS
>>>>
>>>>
>>>> On Thu, Nov 5, 2020 at 1:10 PM w2mmdgcarc <w2mmdgcarc at gmail.com> wrote:
>>>>
>>>>> From: Christopher Wawak [mailto:chris at wawak.org]
>>>>> Sent: November 05, 2020 11:49
>>>>> To: w2mmdgcarc
>>>>> Subject: Where should KC2IEB put HF wire antennas?
>>>>>
>>>>>
>>>>>
>>>>> Hi all! I'm beginning to wonder if my end fed wire antenna is not the
>>>>> best use of the space in my backyard .
>>>>>
>>>>>
>>>>>
>>>>> I'm unable to make most SSB QSOs, and in general I just think I can do
>>>>> better. I've got a good ground near the entry to the shack, and I've got 5
>>>>> or 6 counterpoises laid down sort of randomly around the area connected to
>>>>> the ground lug on the 9:1 unun. Weak FT8 connections are great, but SSB
>>>>> phone is just downright difficult. Unless I'm doing something really wrong,
>>>>> I'm open to changing this entirely.
>>>>>
>>>>>
>>>>>
>>>>> Unfortunately, I'm really, really overwhelmed with the options I have.
>>>>> I'd like to find one wire antenna that would fit in the confines of my
>>>>> yard, and allow me to operate on 60/40/20/17/15/10, with a tuner is fine.
>>>>> Not super excited about 75/80, at least for now.
>>>>>
>>>>>
>>>>>
>>>>> Location:
>>>>> https://www.google.com/maps/@39.9167718,-75.0496759,70m/data=!3m1!1e3
>>>>>
>>>>> (you can right click on the map and get distances if you like)
>>>>>
>>>>>
>>>>>
>>>>> The lot is 70' wide. There's a couple trees, all spaced around 50ish
>>>>> feet apart. Don't worry, I've got drawings below.
>>>>>
>>>>>
>>>>>
>>>>> Right now, the unun is about 6' high, and the wire runs from there to
>>>>> probably about 20-25' high. The wire itself is 84' long. I might be able to
>>>>> get it a few feet higher on both ends. I'm a little shy with the antenna
>>>>> launcher.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> I've thrown some pictures up on a link in case anyone is willing to
>>>>> take a few minutes to review.
>>>>>
>>>>> https://imgur.com/a/VHmPKOn
>>>>>
>>>>>
>>>>>
>>>>> I'll probably be on the club 2m or 70cm repeaters after 8:30 or 8:45
>>>>> and would love to discuss this further, but appreciate any help on email or
>>>>> radio at all. Thank you!
>>>>>
>>>>>
>>>>>
>>>>> -- Chris
>>>>>
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>>>>>
>>>>
>>>
>>> --
>>> -- Chris
>>> --
>>> -- Chris
>>>
>>
>
> --
> -- Chris
>