Small Antennas

[Steve - WB3HUZ]

Another article on the URI antenna.

http://www.eetimes.com/showArticle.jhtml?articleID=163101726

[WA1GFZ]

Kelly Johnson is the father of the name skunk works and it pisses me off when some fraud pusher uses his name as a sales gimic.

The honor of working there just makes my blood boil when some clown
uses that name to sell snake oil.

[Steve - WB3HUZ]

Who's selling snake oil?

Robert Metcalf is the father of ethernet - the technology and the term.

Tim Berners-Lee is the father of World Wide Web -  the technology and the term.

Hewlett-Packard coined the term personal computer.

Other use these terms all the time.


Li'l Abner used the term Skonk Works long before Kelly Johnson ever did.

What's yer point OM?

[WA1GFZ]

I worked there once and learned what it means to build the best.
Also learned respect for the man and the thought process.

Skunk Works got the name because the location of the building
had a local smell.

[k4kyv]

These yahoos are still in business.  Dummy load with a wire attached

http://www.maxx-com.com/index.html

Wonder why they changed the spelling of the name.  It used to be Max-Com. Max-con would be more appropriate.

Check out the prices.  Right in the same league with audiophool products.

[flintstone mop]

I gotta get me one of these thangs. I likes miracle aerials.
The Unihat Verticle was a pretty good antenna for me on a small lot back in my beginning days on AM 160. Many impressed OM's out there.

Fred

[Glenn K2KL]

Here's another snake oil antenna to add to the list, claims "Efficiency approaches 100%" 3ft high, 40 lbs.... amazing!  :p  :p

You're wasting your time with those monobanders Tom Vu!!  :lol:

[K1JJ]

Gawd....  now introducing the "pigeon coop" antenna -  

So absurd. Reminds me of the old film with the guy trying
to fly with a flapping wings machine.

Someone oughta have a certified 75M "shootout" on the air
where all these wonder antennas are ranked.  On top will
always be a simple, flat top, coax fed dipole. Down -30 db+  
would be these  junkyard wonders...  I wonder if QST would
publish it considering the POed venders.   :lol:

T

[Glenn K2KL]

Yes, the all new asteroid catcher!!!

 ..... when will they learn? gimmick antennas suck! they really do!

I couldn't agree more... coax fed dipoles    

Gawd....  now introducing the "pigeon coop" antenna -  

So absurd. Reminds me of the old film with the guy trying
to fly with a flapping wings machine.

Someone oughta have a certified 75M "shootout" on the air
where all these wonder antennas are ranked.  On top will
always be a simple, flat top, coax fed dipole. Down -30 db+  
would be these  junkyard wonders...  I wonder if QST would
publish it considering the POed venders.   :lol:

T

[Steve - WB3HUZ]

There was a time when coax fed dipoles were looked down on in hamdom.

[Glenn K2KL]

Still today, many "old-timers" poo-poo coax in favor of twin lead, crappy brown ladder line, homemade openwire line, boiling wood spacers in wax etc...

Remember when hams used bed springs and rain gutters as antennas?

There was a time when coax fed dipoles were looked down on in hamdom.

[Steve - WB3HUZ]

Brrrrr... Look here young whipper-snapper. Only a multi-wire flat-top made of phosphor-bronze and  an elevated counterpoise will produce a big signal. Ask Hiram. He'll tell ya.....

What were we talking about. Where's my Geritol?

Still today by many "old-timers"

God forbid if anybody says anything negative about crappy brown ladder line, homemade openwire line, boiling wood spacers in wax etc...

There was a time when coax fed dipoles were looked down on in hamdom.

[Glenn K2KL]

Arghhhh! and don't forget the ole' cage dipole shunny!

Brrrrr... Look here young whipper-snapper. Only a multi-wire flat-top made of phosphor-bronze and  an elevated counterpoise will produce a big signal. Ask Hiram. He'll tell ya.....

What were we talking about. Where's my Geritol?

Still today by many "old-timers"

God forbid if anybody says anything negative about crappy brown ladder line, homemade openwire line, boiling wood spacers in wax etc...

There was a time when coax fed dipoles were looked down on in hamdom.

[K1JJ]

Yep, the feedline choice is not really important as long as it's
matched to the load [coaxial or twin lead] or it's low loss like
GOOD heavy open line and then not needed to be matched.
Never see the difference on the air using a dipole.

The important thing is using an antenna with a minimum input
impedance [minimum size like 1/4 wave for a dipole] to keep
losses down and a certain  height above ground to give an
acceptable vert take off angle and stay above the house crap.

Those fag antennas are nothing more than parallel resonant
circuits using a coil and a homo garbage can as a capacitor. Low
input impedance. If someone were gonna go thru that type of
effort to make mini antennas for 75M,  you'd think they'd at least
make up a  10' square copper loop from 2" tubing to
give it a chance to perform at those single digit impedances..  
Even a small, center fed 50' long dipole is better.

[BTW, Steve, you have value too.]

T

[WA1GFZ]

I've always run open wire line to the 160 meter dipole for an antenna that covers all bands.
I just spent the past couple days doing lightning testing at 1000 amps.
Shielded wire is a big help and a great isolator.  Open wire line provides no protection until you hit the tuner or a spark gap. Coiled baluns of coax and the grounded shield can make a big difference.

[K1JJ]

Hi Franz,

I'm in the process of wiring up my feedlines for a bunch of 6M
Yagis. I intend to use a 1/2 wave coiled coaxial balun at the
feedpoint and plan to ground the three associated shields to the
boom.

So, how does the coiled coaxial balun help for lightning? And,
please describe the advantages/path  to grounding the shields
at the feedpoint/ boom vs: letting them float...

[The coaxial balun is an elec 1/2 wave of RG-213 with one end
connected to one half of the dipole el along with the feedline -  
while the other end of the coax balun goes to the other half el.
Forget the T match for now]

T

[K1JJ]

Still today, many "old-timers" poo-poo
coax in favor of twin lead, crappy brown ladder line, homemade
openwire line, boiling wood spacers in wax etc...

Yep.

Whenever I hear someone say coax sucks compared to open
wire, I just remind them that the loudest signals/stations  on
the band here in the NE run coax/heliax.  Just axe Chuck/K1KW,
 Steve/WA1QIX, Gary/INR. Bill/GF, Tina/IA, Bob/KBW, Mike/ZE,
and theres many others. [I run all Heliax or coax, but still can't
compete with those guys... sigh... ]

Openwire is FB as well as coax. There are advanatges and
disadvantages, but it's not on-air performance.

Personally, I like openwire for connecting together a many
element phased array, esp if the eles are full wave center
fed like lazy H's, etc. Also, even connecting together standard
Yagis is OK wid openwire if it's easier than using coax with
many connectors and matching lines. Right now I'm building
a twelve Yagi array consisting of 2el beams for 6M. It's so
simple to use a T match at each Yagi to bring it up to 200
ohms and feed them directly with 200 ohm, 1/2" spaced open
wire. Just space the Yagis 1/2 wave apart and flip the connections
at each Yagi.  In contrast, it would take about 700' of coax and
60 connectors to do the same job with matching sections, etc.
No contest.

But for regular 50 ohm antennas, nothing beats running a
single BIG 7/8" or 1 1/4" Heliax underground to the tower
and using a remote controlled  antenna relay system to select
the various antennas.  

The loss of openwire in the REAL world works out to be about
the same as 1 1/4"  heliax when both are matched. This is
based on actual measurements on 432 mhz and makes openwire
about 20% more lossy than the charts say. Your mileage may
vary on HF due to less skin effect, etc..

There's TONS of surplus/scrap Heliax available now with all the
tower changes going on. It's cheaper to buy than coax if you find
the right sources.

T

[Steve - WB3HUZ]

Ashtabula Bill runs open wire line. He has a bigger signal on all the bands than any of those guys you mentioned have on any one band.

http://www.amwindow.org/audio/mov/w8vyz.mov

[K1JJ]

So that's where his "ain't a slop bucket..."  quote came from... :lol:

Radio Moscow ran openwire too - that's fact!

T

[WB3JOK]

If someone were gonna go thru that type of
effort to make mini antennas for 75M,  you'd think they'd at least
make up a  10' square copper loop from 2" tubing to
give it a chance to perform at those single digit impedances..

My 8' square of 1" tubing works ok on 75m, but about -5db to a dipole according to various calculator programs (only -1db on 40m). Definitely not as good as a dipole but there's no place to put one on my 80x80 lot. Your suggestion of 2" tubing would be better (and quite a bit more expensive). Silverplating might help a little too.

The radiation resistance is not, unfortunately, even single digits, it's down in the tens of milli-ohms, which is why just a few milliohms of resistance in the loop conductor costs you db's...

I think that's why the really tiny antennas are not going to work well on low HF. Not only does the SWR bandwidth get so small (it is quite possible to make a loop that is too narrow for 2.7 KHz wide phone signals) but the radiation resistance drops faster than the loss resistance as the loop shrinks and a superconducting material would be required to minimize the losses.

-Charles
ps What's a homo garbage can??

[WA1GFZ]

Tom
we should have a conversation on my latest grass hopper linghtning
edmucatin. Our set up can go to 10,000 amps but have not turned up
the juice yet. You would love the storage caps for mr ugly.

[Steve - WB3HUZ]

Dat's right! These are FACTS recently published in Pravda.

So that's where his "ain't a slop bucket..."  quote came from... :lol:

Radio Moscow ran openwire too - that's fact!

T

[K1JJ]

Dat's right! These are FACTS
recently published in Pravda

"In the Soviet Union we have no problems, especially with
coax - unlike the wasteful United States.  All Soviet citizens
happily use superior open wire designed by our Soviet engineers
and stamped with the communist party seal.  These are facts! "

[WA1GFZ]

and in 7 years all the coax in the US will turn brown and we will strap them into the ground.

[Steve - WB3HUZ]

DAT'S RIGHT! (That's right)


Now, let's talk about something important, like...... Communism. And how to keep the echo on your voice.