When you are measuring gain, if dBi isn't specified it is normal to assume
dBd. I cannot get that JoGunn page to load and display, but based on what
you have said, the better, or should I say, more believable one is the
Maco. Those gain numbers seem high by a bit for a four element antenna,
but there may be some advantage from the dual polarity, but I doubt it, as
the power is split between Hand V as well going in. And 4 elements/16 foot
boom, 27 MHz sounds much closer to right than 8' boom 3 elements and 14
db. Those are just plain wrong, or at least lack reference.

The ARRL handbook years ago had a construction article on a ten meter
beam, that I scaled very successfully to 15 meters. 12 foot boom three
eleemnts, made from basic aluminum tubing, probably cost well under $100
to build today. But you'd need to be handy with a 'grid dip meter" to get
it right. Just another thought.


My $0.02

getting ham license and operating ten meters, I'd guess you're
actually interested in talking to someone, so 11 meters is probably better
for that. I frequently listen on 27.185 as an indicator of weather or not
ten meters is open. Lots of activity from about 26.8 thru 27.6 or higher,
nothing above 28 except some lonely beacons...true shame. But if you go
beyond the ten meter deal, and get with the other HF bands or 2 meters,
440, etc, you'll have a blast, and the code no longer stands in the way...

Good luck with the Maco.

GeorgeC
W2DB
Awstin, TX

root wrote in
:

When you are measuring gain, if dBi isn't specified it is normal to
assume dBd. I cannot get that JoGunn page to load and display, but

George,

Fundamental relationships depend on dBi, it is dBd that is the fudge.

dBd seems to have its popularity from the mistaken view by some that
because it is not possible to construct a real isotropic radiator, that dBi
doesn't have a real meaning.

Owen

"Stan Cooper" wrote
The Maco has a 16 foot boom and an advertised gain of 12.5 db, while the
JO GUNN has an 8 foot boom and an advertised gain of 14.5 db. I know there
is a lot of smoke and mirrors involved with advertised gains and so my
question is...is it possible for the JO GUNN to perform as well as the
Maco antenna?

The GUNN is of much stronger construction and a smaller windload so I'd
rather put it up, but the short boom makes me wonder if the gain and
rejection numbers are suspect.

Any help would be greatly appreciated, antenna choices, price tags and
urls below.

snip

Stan
The Maco antennas are built here in Memphis, and are not of a high
quality. If
I had to use one of their products, it would be a pair of
horizontal-stacked V-quads.
Small, light, works well and can be easily re-tuned to 10 meters later on.
The Jo Gunn model is a copy of the Charles "Gizmotchi" antenna ( still
being made,
by the way). Construction is better, tubing fit and finish are quite good,
but the gain
figures are really about 7 dbi for both of the antennas.
Gain figures are inflated to catch a sale, so I'd consider quality,
price, and strength
of materials/design as more important factors.
I've got enough tubing in my antenna junk to build a 3 element Gizmotchi
for 10
meters, and I might just do that, for the sake of having something different
in the
neighborhood.

Mike W5CHR
Memphis

Stan Cooper wrote:
...

You might as well check out this page, you can find the prices on a link
on the page ...

http://www.gizmotchy.com/

Regards,
JS

David G. Nagel wrote:

I don't know if you have considered it but I would like to suggest that
you look into ham radio. It is a more adventurous hobby,one that offers
greater opportunity to exercise your operating skills. By and large the
licensed ham radio operators offer a courteous, friendly and extremely
helpful environment. I have to assume that since you are here looking
for assistance you already have a feeling for all this.
Getting a ham license has never been easier. There are only three
classes of license now, Technician, General and Extra. The code test has
been eliminated so that shouldn't be a problem.

Since he did not say where he is, your answer may be wrong. While I
agree with it in principal, not everyone has it so easy. Here in Israel
there still is a code requirement, testing is twice a year, and ANY
permanent antenna requires a permit which no one seems to know how to
get. Technicaly any operation over 20 watts EIRP requires radiation
level certification.

But then CB is just as bad. Except for a few off-roaders who have not gone
to 446 mHz it's even deader than ham radio.

Geoff.


--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM

Owen Duffy wrote:

George,

Fundamental relationships depend on dBi, it is dBd that is the fudge.

dBd seems to have its popularity from the mistaken view by some that
because it is not possible to construct a real isotropic radiator, that dBi
doesn't have a real meaning.

Owen

At least one manufacturer has taken advantage of the fact that, unlike
dBi, dBd has no universal definition. Some think it's dB relative to a
dipole in free space; others think it's relative to a dipole mounted
over ground. And few seem to realize that the difference between the two
is typically 4 - 6 dB. Creative marketeers are able to capitalize on
this confusion, and have.

Roy Lewallen, W7EL

Geoffrey S. Mendelson wrote:
David G. Nagel wrote:

I don't know if you have considered it but I would like to suggest that
you look into ham radio. It is a more adventurous hobby,one that offers
greater opportunity to exercise your operating skills. By and large the
licensed ham radio operators offer a courteous, friendly and extremely
helpful environment. I have to assume that since you are here looking
for assistance you already have a feeling for all this.
Getting a ham license has never been easier. There are only three
classes of license now, Technician, General and Extra. The code test has
been eliminated so that shouldn't be a problem.

Since he did not say where he is, your answer may be wrong. While I
agree with it in principal, not everyone has it so easy. Here in Israel
there still is a code requirement, testing is twice a year, and ANY
permanent antenna requires a permit which no one seems to know how to
get. Technicaly any operation over 20 watts EIRP requires radiation
level certification.

But then CB is just as bad. Except for a few off-roaders who have not gone
to 446 mHz it's even deader than ham radio.

Geoff.


Geoff;

Your are right in one sense, however the antenna's in question are, I
believe, USA products so it is fairly save to assume that the writer is
a USA resident.

From your comments I assume (that word again) that you are a resident
of Israel. Given the situation there I can see why the government would
try to make it hard for someone to install and operate a radio station.
I look forward to the day when everyone in the Mideast can live together
in peace and harmony.

Until that time thank you for your comments.

Dave WD9BDZ

Roy Lewallen wrote:
Owen Duffy wrote:

George,

Fundamental relationships depend on dBi, it is dBd that is the fudge.

dBd seems to have its popularity from the mistaken view by some that
because it is not possible to construct a real isotropic radiator,
that dBi doesn't have a real meaning.

Owen

At least one manufacturer has taken advantage of the fact that, unlike
dBi, dBd has no universal definition. Some think it's dB relative to a
dipole in free space; others think it's relative to a dipole mounted
over ground. And few seem to realize that the difference between the two
is typically 4 - 6 dB. Creative marketeers are able to capitalize on
this confusion, and have.

Roy Lewallen, W7EL


Roy;

I think that this a subject custom made for the phrase: Your Mileage May
Vary.

Dave WD9BDZ

David G. Nagel wrote:
Your are right in one sense, however the antenna's in question are, I
believe, USA products so it is fairly save to assume that the writer is
a USA resident.

I thought so, but sometimes the people asking are not. They only have
access to U.S. manufacturer's products and catalogs via web sites,
with no local dealers.


From your comments I assume (that word again) that you are a resident
of Israel. Given the situation there I can see why the government would
try to make it hard for someone to install and operate a radio station.

Well, actually it's not. The antenna restriction is because the
"cellphone towers will kill you" people have forced laws through to prevent
anyone setting up a radio transmitter in their neighborhood.

The morse code requirment is because the people who run the Israel equivalent
of the ARRL pushed the Minstry of Communications to keep it. It keeps out
new hams from foreign countries. I have no idea how they handle visiting
operators now.


I look forward to the day when everyone in the Mideast can live together
in peace and harmony.

Thanks,

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM

Hello Stan:

Try to find a Hy-Gain 3 element yagi beam that uses the Hairpin Matching
system. And use the Hy-Gain Balun. That way you won't have the
significant loss of the Gamma Match.

Jay in the Mojave

Stan Cooper wrote:
Hello I hope I'm not intruding by asking for advice on a CB antenna but I
figured this would be the group to ask about such things for the straight
scoop. At any rate I'm considering a store bought beam with both vertical
and horizontal polarization and my choices are limited to these two below.
(not many being manufactured anymore)

The Maco has a 16 foot boom and an advertised gain of 12.5 db, while the JO
GUNN has an 8 foot boom and an advertised gain of 14.5 db. I know there is a
lot of smoke and mirrors involved with advertised gains and so my question
is...is it possible for the JO GUNN to perform as well as the Maco antenna?

The GUNN is of much stronger construction and a smaller windload so I'd
rather put it up, but the short boom makes me wonder if the gain and
rejection numbers are suspect.

Any help would be greatly appreciated, antenna choices, price tags and urls
below.

73
Stan

MACO-Shooting Star $279.95
http://www.mpaudio1.com/Macobeamantennas2.html

JO GUNN 3 + 3 STAR $382.00
http://tinyurl.com/6hzteu

Oh btw, I'll be tower mounting it about 40' from the ground and turning it
with a hamIV rotator.

Thanks again.