On Thu, 27 Apr 2006 12:13:46 -0700, Roy Lewallen
wrote:

jawod wrote:
I was listening to 40M the other night and a reasonably clear SSB signal
came from a guy in Pennsylvania using 100 W to a rain gutter.

It was apparently raining at the time in PA.

All the mathematical modeling and tweaking discussed in this group ...
I thought the successful use of a rain gutter deserved some praise here.

Why? There's nothing unusual or exceptional about it.

Indeed.

Whilst it might have, and is probably still often done, it is unlikely
to comply with limits on Maximum Permitted Exposure to EMR. It has a
host of other disadvantages (EMC incompatibility, TVI/RFI, unreliable
performance to name a few).

The configuration is known as a CIA Special down here, being a covert
antenna. I suppose it is commonly done in places where covenants
prohibit external antennas.

....

Anyone who's been a ham for a few years probably has a handful of
similar stories. What conclusions should we draw from them?

Anything and everything "works" in the minds of amateurs. In the minds
of some, a few QSOs is adequate proof that something "works", though I
know you think differently Roy.

Owen
--

I've run the max permitted exposure calculators on some of my more
egregiously located antennas, and you'd be surprised what it takes to
exceed the limits if you're running 100W SSB. I've got to be in
compliance for people on adjacent balconies, and it's pretty easy on
HF.

According to http://n5xu.ae.utexas.edu/rfsafety/

Using 20% duty cycle for SSB to calculate average power of 20W into a
2.2dBi gain antenna (a pretty good rain gutter) at 7MHz, your neighbor
has to be a whopping 1.46 feet from the antenna. You only have to be
0.86 feet away.

It is a good point that the stealth crowd should be checking these
things out, though, as at least the apartment crew are using their
antennas in densely packed quarters.

I have discovered from said site that I should not run 100W 6m RTTY
into my Moxon lest the balcony next door become a more-than-allowed
uncontrolled exposure zone. On the other hand, maybe that's a handy
use for 25dB front to back ;-)

Dan
N3OX

Owen,

Sorry I'm being a bit USA-centric. Maybe MPE limits in VK are more
strict?

3.68 milliwatts per square centimeter here at 7MHz.

I just noticed the "whilst" :-)

-Dan

On 27 Apr 2006 15:11:46 -0700, "
wrote:

Owen,

Sorry I'm being a bit USA-centric. Maybe MPE limits in VK are more
strict?

Dan, the greater issue here is the interpretation of of whether the
radiator is accessible to members of the general public. If the kids
next door come into the yard to retrieve their ball, it may be
considered that it is accessible to the general public. Occupants of
the premises (eg the rest of the family and visitors) may be
considered to be the general public.

Owen


3.68 milliwatts per square centimeter here at 7MHz.

I just noticed the "whilst" :-)

-Dan
--

Another item that also works especially on 6m, throw an old bed spring on
the roof!
73's

"Owen Duffy" wrote in message
...
On Thu, 27 Apr 2006 12:13:46 -0700, Roy Lewallen
wrote:

jawod wrote:
I was listening to 40M the other night and a reasonably clear SSB signal
came from a guy in Pennsylvania using 100 W to a rain gutter.

It was apparently raining at the time in PA.

All the mathematical modeling and tweaking discussed in this group ...
I thought the successful use of a rain gutter deserved some praise here.

Why? There's nothing unusual or exceptional about it.

Indeed.

Whilst it might have, and is probably still often done, it is unlikely
to comply with limits on Maximum Permitted Exposure to EMR. It has a
host of other disadvantages (EMC incompatibility, TVI/RFI, unreliable
performance to name a few).

The configuration is known as a CIA Special down here, being a covert
antenna. I suppose it is commonly done in places where covenants
prohibit external antennas.

...

Anyone who's been a ham for a few years probably has a handful of
similar stories. What conclusions should we draw from them?

Anything and everything "works" in the minds of amateurs. In the minds
of some, a few QSOs is adequate proof that something "works", though I
know you think differently Roy.

Owen
--

Howard W3CQH wrote:
Another item that also works especially on 6m, throw an old bed spring on
the roof!
73's

"Owen Duffy" wrote in message
...

On Thu, 27 Apr 2006 12:13:46 -0700, Roy Lewallen
wrote:


jawod wrote:

I was listening to 40M the other night and a reasonably clear SSB signal
came from a guy in Pennsylvania using 100 W to a rain gutter.

It was apparently raining at the time in PA.

All the mathematical modeling and tweaking discussed in this group ...
I thought the successful use of a rain gutter deserved some praise here.

Why? There's nothing unusual or exceptional about it.

Indeed.

Whilst it might have, and is probably still often done, it is unlikely
to comply with limits on Maximum Permitted Exposure to EMR. It has a
host of other disadvantages (EMC incompatibility, TVI/RFI, unreliable
performance to name a few).

The configuration is known as a CIA Special down here, being a covert
antenna. I suppose it is commonly done in places where covenants
prohibit external antennas.

...

Anyone who's been a ham for a few years probably has a handful of
similar stories. What conclusions should we draw from them?

Anything and everything "works" in the minds of amateurs. In the minds
of some, a few QSOs is adequate proof that something "works", though I
know you think differently Roy.

Owen
--



I just think the great stories of rain gutters, chimneys, fire escapes,
etc. reflect the spirit of individual experimentation that, to me, is
the heart of ham radio. Maybe not the brain, but the heart.

John
AB8WH

jawod wrote:
I just think the great stories of rain gutters, chimneys, fire escapes,
etc. reflect the spirit of individual experimentation that, to me, is
the heart of ham radio. Maybe not the brain, but the heart.

You must love Kurt N. Sterba's tales of using bedsprings,
ladders, and garbage cans for antennas.
--
73, Cecil http://www.qsl.net/w5dxp

I just think the great stories of rain gutters, chimneys, fire escapes,
etc. reflect the spirit of individual experimentation that, to me, is
the heart of ham radio. Maybe not the brain, but the heart.

You must love Kurt N. Sterba's tales of using bedsprings,
ladders, and garbage cans for antennas.

And don't forget the (QST?) pictures of "car antennas" several years
ago: two cars sitting almost bumper-to-bumper and fed with coax as a
very-low dipole at the almost-touching bumpers. Truly a "car antenna"
(but not very mobile)!

--
--Myron A. Calhoun.
Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge
PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785) 539-4448
NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol)

wrote in message ...
I just think the great stories of rain gutters, chimneys, fire escapes,
etc. reflect the spirit of individual experimentation that, to me, is
the heart of ham radio. Maybe not the brain, but the heart.

You must love Kurt N. Sterba's tales of using bedsprings,
ladders, and garbage cans for antennas.

And don't forget the (QST?) pictures of "car antennas" several years
ago: two cars sitting almost bumper-to-bumper and fed with coax as a
very-low dipole at the almost-touching bumpers. Truly a "car antenna"
(but not very mobile)!

--Myron A. Calhoun.


Now THAT one I haven't seen.

HOWEVER, I DO have a picture (Dad's) of two hams and their cars side by
side. W9SH and W9IT

Of course they had call plates! What'd you expect! Ya think QST'd print it
????

73, Steve, K9DCI

And, also, makes great Stacked helical's for 2304! Jim NN7K

jawod wrote:
Howard W3CQH wrote:

Another item that also works especially on 6m, throw an old bed spring
on the roof!
73's