I'm not sure that it's that they don't know any better, but that it
suffices for their needs. If you don't have a specific purpose in mind,
other than make contacts, and you have a limited amount of space, why
not use it? Would a much larger antenna really be much better in that
case? I find that most hams don't have a specific purpose in mind when
they select an antenna, they just want a "good antenna" but an antenna
that's good for one purpose may be crap for another. If you know what
you're trying to do, you can look at it through the lens of your purpose
and actually get something that suits your needs.
I didn't see your answers to Rick Hiller's questions, but they are very
important to understanding what antenna you should get. What kind of
operating do you expect to do? Contesting? Nets? DXing? "Rag Chew
and the usual BS"? What? Is there a particular direction you want to
send a signal? What kind of space do you have for an antenna? Do you
have any objection to laying out radials on the ground? What's your
budget? How much work are you willing to do to make the antenna
happen? Do you have an HOA CC&R that you have to abide by?
I was pretty happy with the dipoles I used to have back in Ohio. My 20m
dipole was fed with the same line as my 40m dipole and hung underneath
it, looking kind of like an archery bow. A 20m dipole is only about 35
feet long and only has to be about 15 feet off the ground to radiate
like people think a dipole radiates and I can put two of them at right
angles in the back yard of my 1/6 of an acre lot, one N-S and one E-W.
To put them up, I would tie one end of each to an eye screw in the
soffit of my house and the other end to a 15 foot mast along the back
fence. A couple of feed lines and a coax switch in the shack (or remote
antenna switch, if you wanted to get fancy) plus baluns, if you feel
like, and I could go world wide no matter where they are. You're
looking at a couple hundred dollars for that set up, assuming you buy
baluns and the coax switch. Maybe more if you put in tensioners so the
wire doesn't snap in a strong wind. You can use the wire itself as the
structural element, or you can use the twine to support the copper. If
you use the wire to support itself, get hard drawn copper so that it
doesn't stretch. As much.
Alternately, you could look into the TH-11DX at 100 feet that I
mentioned before. You should be able to get all that for $10,000, I'd
guess, assuming your lot is big enough for a 100 foot tower and the
county engineer approves your plans and permits. I know of at least one
HOA where that might fly, but unless you live near 249 and Louetta, you
probably don't live there.
On the other extreme, you could buy a metal Slinky(tm) and an antenna
tuner with a single wire output and use that. My late friend Steve
worked the world on 150 watts and a slinky in his shack until he
upgraded. That's what? $10 for a slinky and I can loan you a tuner I'm
not using any more.
My current antenna, which I am not really happy with, is a trap dipole
in the attic. I'm mostly unhappy because picks up every little bit of
electronic noise generated in the house, but there are other reasons,
not having to do with the construction technique. Large parts of every
band are completely unusable and there is a high noise floor on all of
them. I made the traps from coax and PVC fittings, based on an article
I read in QST. This antenna used to work notably better than it does, I
suspect because the HVAC guys damaged it when they replaced my unit this
summer, but it really never worked very well, especially for receiving.
I picked up the book /Receiving Antennas for the Radio Amateur/ but I
haven't put any of the ideas in it into practice, even though I have
some ferrite rods specifically for that purpose. Eventually, I will
have to chase down the noise, but during the 10m contest a few years
ago, I found that just putting a vertical antenna outside reduced the
noise dramatically while the signal levels were unchanged, so I'm going
to change to an exterior antenna first.
My current plan for that exterior antenna calls for winding 1888 inches
(157 feet or so) of 20-gauge magnet wire around five foot lengths of
2-inch PVC. It won't resonate anywhere, not intentionally anyway, so
I'm going to feed it through a remote antenna tuner and lay out a bunch
of radials made of 26-gauge cross-connect wire, a spool of which I
happen to have. I don't know how many radials I'll lay out, but the
idea is to lay them out such that the ends are about a foot apart. I
hope it will cover all of the HF bands, but I'm not even going to try to
analyze it. If I can get it to work on 160 and 80 and perhaps 40, but
have problems with one or more of the higher bands, I might just buy a
second antenna for those higher bands. I kind of have vague plans of
making two of them and using a phaser to make it a directional phased
array, but every time I start thinking about it, I lie down until the
feeling passes. If it doesn't work on some band (probably because it is
accidentally resonant on that band--it's possible to end feed a resonant
half-wave dipole, but the techniques to do that are specialized) then I
may ignore it or I might try something to fix it. A capacitance hat or
something. Who knows?
I live in an HOA where the operative phrase is "seen from the street"
and I can put up anything I want as long as you can't see it when parked
in front of the house and as long as the neighbors don't complain. Wire
antennas are such an odd thing that, in my experience, the management
company doesn't have a clue that they should complain about them if they
see them, but a column of PVC behind the house won't even be seen. Just
don't hang laundry from it because clotheslines are expressly
forbidden. I might be able to get away with a "spider beam" at about 20
feet, but that costs more money than I am willing to spend right now,
and besides I'm more interested in the "Low Bands" than in 6-20m
There's one opinion, worth what you paid for it. I hope it helps.
On 12/22/20 2:11 PM, Mark Brantana via BVARC wrote:
Jonathan
I totally agree with your insight. Still have not found a single
objective review of the antenna. Dave Casper is going to do one. That
is why I was looking to see if anyone here has tried one. Meanwhile,
yes, there are people who don’t know any better, and cognitive
dissonance is very real. No one wants to admit to themselves that they
bought into something that was wrong. I noticed that almost every one
of the hundred or so antennas on eHam got 5-starts. Predictably they
also write paragraphs praising their antennas. Interesting. So I
totally agree with your premise.
Mark
N5PRD
Sent from my iPhone
On Dec 22, 2020, at 8:53 AM, Jonathan Guthrie via BVARC
<[email protected]> wrote:
You ask why there are lots of reviews from people who love the
Isotron even though you can't find anyone who has used it. I don't
know why you can't find anyone who has used it, but I can explain
some (most? all?) of the good reviews.
First, some people tend to give five-star reviews for stuff they
like, but not love. I tend to not give five-star reviews for 'seems
to work the way it's supposed to' because that's not outstanding,
it's expected, but I am known to be odd. Second, some people are
likely fans of Isotron for other reasons and they would give a five
star review to an such an antenna made of wet string lying on the
ground and disconnected from the feedline.
The thing is, most people have no real idea how to evaluate an
antenna and definitely don't have the setup for it. The equipment
most hams used to evaluate an antenna is an SWR meter, but an SWR
meter, in and of itself, tells you precisely nothing about how well
an antenna is working. The proper tool to use is a field strength
meter, but using one of those for an HF antenna usually requires more
land than a typical ham has access to and more time and effort than
they're likely to want to go to. So, what is someone to do?
Well, when I was looking into the "EH Antenna" (don't judge me--I
seek the Holy Grail of antennas just like every ham) I found that
typically people would describe "far off" stations as loud or talk
about working stations at so many km. For a receiving antenna,
efficiency is not paramount, so signal strengths are a misleading
measure, and the distances for stations worked were on the order of
150km, as I recall. I'm not impressed by working a station 150km
away on 40m using a small antenna, but if you're getting contacts
through this sheet metal contraption, you can't say that it doesn't
work. If it's working for you, meaning you're making Q's, then why
not give it a positive review?
Antenna selection is often a matter of balancing what you want to do
against how much money you have to spend and other restrictions you
might have. There's an old list of "antenna truths" that I saw that
began with "Any antenna is better than no antenna" and for many
people, the Isotron is what they can get an use and it does what they
need it to do, so they give it five stars.
A good option for 20m? Have you considered a TH-11DX up about 100 feet?
On 12/21/20 2:45 PM, Mark Brantana via BVARC wrote:
Thanks to everyone for the insightful comments. I will put the light
bulb antenna on my list. Could an LED work? It should consume less
power.
How come, though, there are so many comments from those who have no
experience with the isotonic antenna, yet eHam is loaded with
reviews from people who love them? Rick makes a good technical point
I need to consider, but don’t understand why wHam has 78 reviews in
the past 180 days give a 5-star average rating for the antenna, and
3.9-star average overall. I get that there have been disappointing
novel antennas in the past. Anyone remember the can field antenna?
I am looking for a good option for 20 m and have the coax run and
waiting for the right selection. Open to ideas.
Mark N5PRD
Sent from my iPhone
On Dec 21, 2020, at 10:39 AM, Jonathan Guthrie via BVARC
<[email protected]> wrote:
I have one I got from K5LDD. It's for 80 meters, it comes with no
instructions and some parts may be missing. You want it?
It should work reasonable well as a radiator, physically small
antennas have been used by many people with great success, but its
feedpoint impedance is going to vary rapidly with frequency and
that means it's going to be fiddly to use. At my age, I dislike
fiddly.
On 12/21/20 9:12 AM, Mark Brantana via BVARC wrote:
Thank you, Rick.
Saw one on Dave Casler’s blog last night. He is planning to test
it out. They are said to be good on one band only. Have been a try
around 30 years. I saw a surprising number of 5 star reviews. Has
anyone here tried one? Could just come down to cognitive
dissonance on their part.
Mark
N5PRD
Sent from my iPhone
On Dec 21, 2020, at 6:25 AM, Rick Hiller via BVARC
<[email protected]> wrote:
Very high Q. Finicky. Poor radiator.
Sent from my i-Thingamajig
On Dec 21, 2020, at 12:14 AM, Michael Monsour via BVARC
<[email protected] <mailto:[email protected]>> wrote:
You might have the same luck using a light bulb for an
antenna-at least it will be cheaper
On Sun, Dec 20, 2020 at 10:32 PM Mark Brantana via BVARC
<[email protected] <mailto:[email protected]>> wrote:
Anyone have any experience with an Isotron antenna?
Mark
N5PRD
________________________________________________
Brazos Valley Amateur Radio Club
BVARC mailing list
[email protected] <mailto:[email protected]>
http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org
<http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org>
________________________________________________
Brazos Valley Amateur Radio Club
BVARC mailing list
[email protected] <mailto:[email protected]>
http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org
<http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org>
________________________________________________
Brazos Valley Amateur Radio Club
BVARC mailing list
[email protected]
http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org
________________________________________________
Brazos Valley Amateur Radio Club
BVARC mailing list
[email protected]
http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org
--
Jonathan Guthrie
ARS KA8KPN
________________________________________________
Brazos Valley Amateur Radio Club
BVARC mailing list
[email protected]
http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org
________________________________________________
Brazos Valley Amateur Radio Club
BVARC mailing list
[email protected]
http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org
--
Jonathan Guthrie
ARS KA8KPN
________________________________________________
Brazos Valley Amateur Radio Club
BVARC mailing list
[email protected]
http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org
________________________________________________
Brazos Valley Amateur Radio Club
BVARC mailing list
[email protected]
http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org
--
Jonathan Guthrie
ARS KA8KPN
________________________________________________
Brazos Valley Amateur Radio Club
BVARC mailing list
[email protected]
http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org
