KB8IV wrote:
"I`m wanting a good 10 meter antenna for local stuff and was thinking
about a conventional vertical...then I thought maybe I could do without
the radial system---."

Good thinking. I worked for an oil and gas company which was assigned a
33 MHz frequency shared with a few others in the same industry but
available to us almost at any location within the U.S.A. We made good
use of the frequency for land mobile operations with dozens of fixed
stations and hundreds of mobile units. It worked very well for the radio
"line-of-sight. Usual FM base station power was 500 watts. The mobiles
were 50 watt units. Higher base station power is justified by noiser
receiving conditions in a mobile.

In our international operations we had many HF installations. Some were
AM and some were SSB.

I made a trip to Bolivia to relocate a HF station from a site which was
being seized by the government to accomodate homeless rural people who
were descending upon La Paz to seek their fortunes. Relocation of the
station was easier said than done but was ultimately successful. We had
offices in La Paz and in Cochabamba and we were drilling in the Chaco
Jungle.

While in Bolivia, I got a request from Argentina. They wanted an
aircraft beacon installed on Tierra del Fuego, local land mobiles that
worked, and radio between Tierra del Fuego and Buenos Aires. Strikes
frequently interrupted normal communications. The Peronistas wanted Juan
Peron back and the strikes were part of their agitation. So, I went to
Argentina.

In Argentina, we had RCA and RCA Radiomarine SSB equipment. Our aircraft
were equipped with Collins equipment which was dependale and our pilots
knew how to use it.

The RCA SSB was a problem. The automobile units had plastic coil forms
which melted in normal service. This was far removed from the equator.
It was near the antarctic and damn cold.

Operations were a problem. Base stations were used to communicate
between land bases, vehicles, boats, and tankers taking on oil we had
found and were producing. Multiple crystals meant operators often
couldn`t communicate because they were often switched to the wrong
channel. They also were mystified by knobs identified as "speech
clarifiers".

Fortunately we had some 5-watt Motorola Handitalkies on our stateside 33
MHz FM frequency, on loan to our Argentine operation.

After I installed the low-frequency aircraft homing beacon, the next
problem was getting reliable communications between our main bases in
Rio Grande and San Sebastian, almost 40 miles apart.

This is a land where hurricane force winds blow nearly every day. The
wind is so prevalent it is relied upon for aircraft operation.
Commercial air service to Rio Grande was cancelled when the wind was
calm as the runways were too short for take-offs and landings in the
calm. Commercial flights used DC-6`s (Aerolineas) and C-46`s (Austral).
Our company flew a DC-3 back and forth between Buenos Aires and Tierra
del Fuego. We had Beechcrafts on the Island.

For line-of-sight we needed elevation for 33 MHz antennas. We had
welders, line pipe, steel handbooks and I had a slide rule. So, I went
to work and produced guyed towers at both ends of the path. They were a
little over 100 feet and I put vertical homemade resonant vertical
centerfed dipoles for 33 MHz at their tops. These were connected by RG-8
with the 5-watt radios in the offices. Voila! We were in business with
full quieting. No bandswitching. No clarifiers. No melted coils in the
Motorolas.

We had a second office in Rio Grande but it didn`t need to talk to San
Sebastian. So I made a short self-supporting line pipe tower for that
office. It was about 30 feet. It too had a vertical dipole and a 5-watt
Motorola Handitalkie. When I made a call on that radio, an oil field
supply company in Midland Texas who shared the frequency came back to
me! We`re talking real DX and it was solid. As has been said, that`s the
way it is when the band is open.

Let me correct a statement in this thread that the loweer dipole element
is a radial. It is not. It is an axial and it radiates. Radials are
supposed to be balanced so that they do not radiate.

It is true that radials provide a 2nd antenna connection as does the 2nd
dipole element. That is where the similarity ends.

For the radio connection with Buenos Aires, the public correspondence
station, Radio Pacheco, seemed to work during telephone strikes. So we
went to work. It operated on certain HF channels. Al Hopson, our chief
pilot in Argentina was also a ham and he had had recognized a
Hallicrafters HT-20 that Glen McCarthy had left behind in the Chaco
Jungle of Bolivia when we bought his consession. Al put the HT-20 away
for safe keeping and asked me if I wanted it. He fetched it for me. I
went to Buenos Aires and visited Radio Boliche, "Barato y chi chi".
While there I bought a 2nd-hand Eddystone receiver that worked good and
was cheap (barato y chi chi just as their slogan said).

Back on the island again, it was out with the slide rule and my precious
copy of Ed Laport`s "Radio Antenna Engineering". When we gave Buenos
Aires a call with that HT-20 connected to that rhombic, we really
rattled their cans. The were very slow to believe that we were so far
away.

We ordered the FM stuff they needed to replace all the SSB crap, and
left them delighted with the improvements already made.

Yes. Centerfed vertical dipoles work fine without radials. They have
nulls at their tip ends which reduce mutual impedance with stuff in
those directions. Centerfed antennas are mostly independent of the earth
at close range when low-angle radiation is considered.

Best regards, Richard Harrison, KB5WZI