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

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 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