Topband: Salt-Water Qth!

Fri Apr 3 16:06:28 EDT 2015

"A LID operating QRO at an excellent northeastern US sea view site with excellent antennas -- is still
only a *loud* LID, who is able to cause a lot more interference and consternation than a weak LID."

The above is an excellent example of "confrontational interoperability," and close to the examples of "good" and "bad' interoperability I share with my students, Guy!!! 😊

72, Jim Rodenkirch K9JWV

> From: k2av.guy at gmail.com
> Date: Fri, 3 Apr 2015 15:59:39 -0400
> To: donovanf at starpower.net
> CC: topband at contesting.com
> Subject: Topband:  Salt-Water Qth!
> 
> On Wed, Apr 1, 2015 at 12:17 PM, <donovanf at starpower.net> wrote:
> >
> > Its not practical to place a vertical closer than 1/4
> > wavelength of an ocean beachfront except in a temporary installation
> > such as a DXpedition.
> 
> Also w2re at hudsonvalleytowers.com wrote:
> 
> >>... "Is there any scientific data in print to prove the theory that ocean
> front property is better than a location inland about a mile or so on a
> ridge overlooking salt water for HF. ... I understand the theory that
> verticals literally in or on the water have a huge advantage."...
> >>
> 
> It is not a theory that there is a remarkable increase in MF transmission
> when closely approaching saltwater waterline. It has been observed over at
> least a half century by what must now be millions of observers, certainly
> the vast majority not hams, observed at least since inexpensive
> transistorized portable radios were available around 1960.
> 
> The 1960 date sticks in my mind because of a story that circulates among
> Berea College alumni to this day about transistor radios scattered among
> 1200 students stuck in a terribly boring required general assembly lecture.
> Some 15 or 20 of these new all-the-rage radios were scattered all over the
> assembly hall, and were tuned in to the 7th game of the 1960 world series
> between Pittsburgh and the Yankees. Back then there were no earbuds to go
> stealth. Volumes were low, but loud enough to hear without the giveaway of
> the radio resting upon the ear. The winning run in the bottom of the ninth
> resulted in barely suppressed cheers and moans and the cumulative uproar of
> whispers mercifully brought the lecturer to a bewildered halt. We received
> an outraged dressing down from the college president who, to his credit,
> was the first up on the stage to figure out what was going on, and who
> apparently was not a baseball fan. I won't get into why I know it was
> terribly boring. But I digress...
> 
> These and millions of others took these radios everywhere with them, and it
> was soon common knowledge that you could hear the New York AM stations all
> day long if you took the radio out over the salt water at east coast ocean
> beaches as far south as Cape Hatteras. Not a bit of theory involved, just
> undeniable observation.
> 
> The wow factor of this has severely diminished since the internet, and
> nobody except hams thinks that hearing NYC AM stations during the day down
> the east coast is the least interesting. The question now is why can't the
> complainer text high definition video to anywhere in the world over the
> internet in five seconds or less. But transistor radios were really neat
> new affordable stuff in 1960.
> 
> The depth of the drop off walking away from the beach, the inverse of the
> improvement walking toward it, exposes the answer to your question.
> Whatever the theory, the fact remains of an often reported sharp change in
> signals across several hundred meters, sometimes in significantly less
> distance.
> 
> The "mysteries" of near-to-ocean propagation or losses become less foggy if
> one always carefully considers ground media loss in discussions. Ground
> losses continue to be the "undiscovered country" of top band transmitting
> antenna discussions, remarkably ignored in many discussions about 160 meter
> antennas that require a counterpoise. These ignored counterpoise issues can
> take back expensive amplifier gain with losses as large.
> 
> Models depend on a monolithic uniform ground all the way to and beyond the
> horizon and uniform to deep depth. Models need this to simplify computer
> computations so they can run on ordinary PC's in times that are measured in
> minutes rather than months or years. Accurate 160m modeling of what goes on
> from 100 meters out in the water, across a sandy beach to 10 kilometers
> inland cannot be accomplished with available resources and program code.
> Some investigators have set up carefully at a site with antenna and serious
> commercial measuring equipment, and have simply been unable to get
> measurements to match a model, regardless of the ground characteristics
> specified in the model.
> 
> At the water line, the remaining difficulty at this point would be support
> of a vertical. An FCP above and parallel to the water line or out over the
> water would be a very efficient counterpoise and quite easy to erect with
> inexpensive materials. A shortened aluminum vertical with large gauge
> appropriately located loading coils could do very well in the short term.
> It would have a narrow bandwidth, not being weighed down and broadbanded by
> ground losses invoked by the antenna and the counterpoise. But the reality
> of salt spray, wind, etc easily renders temporary anything other than a
> tower and guys on piers ala the San Francisco station mentioned earlier.
> And even that would require ongoing maintenance.
> 
> The sea view cliffside location, with steps taken to minimize losses
> directly underneath the antenna, seems best all band all around. Some argue
> there is a surface wave phenomenon right over the water, demonstrated gone
> after a few hundred meters inland. Such an actual propagation mechanism
> will not be had at cliffside, however excellent the site otherwise.
> 
> Perhaps someone who actually owns beachfront, including the sand or rocks
> down to the salt water, lacking contrary legislation, will be able to put
> up something measurable right over the salt water and and keep it up and
> efficient long enough to report results.
> 
> And even if a cliffside sea view location was worth an S unit or two,
> nothing overmatches the dB between the ears. A LID operating QRO at an
> excellent northeastern US sea view site with excellent antennas -- is still
> only a *loud* LID, who is able to cause a lot more interference and
> consternation than a weak LID.
> 
> 73, Guy
> _________________
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