Hi all. I'm sitting here trying to figure out how to get on the air!
I'm in a big apartment building ... I have these hot water pipes which
feed radiators on every floor ... I'm on the 11th floor.

I'm thinking that I can throw 100' wire out the window (to radiate)
and ground to the hot water pipes. Thoughts? Any risk of damage to
the heating system? I don't know how the water's heated...

Thanks,
Rich
(Please don't reply via e-mail ... dead address)

"Rich" wrote in message
om...
Hi all. I'm sitting here trying to figure out how to get on the air!
I'm in a big apartment building ... I have these hot water pipes which
feed radiators on every floor ... I'm on the 11th floor.

I'm thinking that I can throw 100' wire out the window (to radiate)
and ground to the hot water pipes. Thoughts? Any risk of damage to
the heating system? I don't know how the water's heated...

How much power are you planning to run? You could make the radiators hot
with rf, too. The cold-water pipes would be better, as they usually go
directly into the ground, whereas the hot-water system goes into a boiler.
There are a lot of joints in both between you and ground, so it may not
matter much. The pipes won't be very close to true ground potential but may
work as a counterpoise to your wire. Worth a try.

When I lived in Manhattan's East Village in the 1970s, I was on the third
floor of a six-floor building with a fire escape. I scraped 80 years of
paint and scale off the metal and put on a 'crocodile' clip when I wanted to
get on the air. My counterpoise was a piece of insulated wire running along
the baseboards. After working W1AW and mentioning the antenna (the QSL card
came addressed to "Roasted Pigeons") I even got mentioned in the ARRL
Antenna Book! Using about 200 W I was able to work ZL and VK on 40 CW, and I
was surrounded by other buildings. so your wire is worth a try.

73,

"PM"

Rich,
Will the heating pipes work as a 'ground'? Sure, probably,
but you might think about it for just a while. Since the
heating system runs to all parts of the building, that means
'part' of your antenna system is running to all parts of the
building too (all those electronic devices susceptible to RF
interference, you know? Unhappy neighbors?). Any chance of
having access to the roof? That would open up quite a number
of possibly 'better' options.
And just because it's not a bad idea, have you, or can you
find an amateur group in Ankara? I'm sure they could offer a
lot of helpful advice, not just about antennas!
'Doc

I believe that using hot water pipes as a "ground" would be a violation of
the National Electrical Code.

There have been many good articles/threads posted here - many with links to
websites on grounding.
Try googling on ham-radio and grounding ...

Carl - wk3c

"'Doc" wrote in message ...


Rich,
Will the heating pipes work as a 'ground'? Sure, probably,
but you might think about it for just a while. Since the
heating system runs to all parts of the building, that means
'part' of your antenna system is running to all parts of the
building too (all those electronic devices susceptible to RF
interference, you know? Unhappy neighbors?). Any chance of
having access to the roof? That would open up quite a number
of possibly 'better' options.
And just because it's not a bad idea, have you, or can you
find an amateur group in Ankara? I'm sure they could offer a
lot of helpful advice, not just about antennas!
'Doc

Rich wrote:
I'm thinking that I can throw 100' wire out the window (to radiate)
and ground to the hot water pipes. Thoughts? Any risk of damage to
the heating system? I don't know how the water's heated...

I tried that in a dorm at Texas A&M in the 50's. Every AM radio
and most every HI-FI in the dorm quit working when I keyed down.
--
http://www.qsl.net/w5dxp/notuner.htm



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Assuming the hot and cold plumbing is mostly metal pipes.

If possible run more than one ground connecting wire in two or more
different directions. Even long, bent wires are far better than none. If
possible also include a wire to a cold water pipe. Run wires unobtrusively
under carpets, etc. 18 gauge to 14 gauge, bare, enamelled or plastic
insulated wires will do fine.

Don't forget all the mains wiring in the building (and equipment connected
thereto) is also connected to your radio and form part of its ground system.
Every bit of stray inductance and capacitance adds to its lectrical bulk.

Make as much use as possible of the large set of random, cross-connected,
terminated radials in the building. In principle, you have at your disposal
one of the best ground systems for miles around. Connect directly from the
transmitter to it as often as you can.

High voltages between pipes and wiring and nearby equipment are very
unlikely to exist because of the large electrical mass of the whole. And it
is impossible to put one bare foot out of the window to reach the real
ground while turning on the cold tap with your bare hand in the bathroom.

To be absolutely safe start with low power before attempting 100 watts.
Don't exceed 100 watts. I say this simply because I've never used more than
100 watts myself when using the plumbing system as a ground. Never had any
trouble with RF burns. Not even tingling. You and the transmitter are
inside a sort of random Faraday cage.

If an occasonal interference to TV is a problem tackle it from the TV set
end.

Problems, if any at all, get better the lower the frequency. There may be
only one band affected. So avoid it. I've never heard of a problem on
160m. And problems do occasionally arise whatever the ground system when
used with an end-fed wire. Or even with an HF rotateable beam fed over a
balanced line.

With a high random 100 foot wire out of the window, plus a tuner, you will
do very well. By extending the end downwards to make 140 or 150 feet you
will do even better.

The only unavoidable problem lies in the locally-generated noise level at
the lower frequencies.
-----
Reg, G4FGQ

======================================

"Rich" wrote in message
om...
Hi all. I'm sitting here trying to figure out how to get on the air!
I'm in a big apartment building ... I have these hot water pipes which
feed radiators on every floor ... I'm on the 11th floor.

I'm thinking that I can throw 100' wire out the window (to radiate)
and ground to the hot water pipes. Thoughts? Any risk of damage to
the heating system? I don't know how the water's heated...

Thanks,
Rich
(Please don't reply via e-mail ... dead address)

Hi all. Thanks for your replies. To give you more info, I'm only
capable of up to 100w. I'm thinking about adding a Bencher 1.8-30 MHz
Bandpass Filter to my set-up to minimize TV interference (even if I
use a dipole, ref. my other post, " Dipole/Balun? Commercially
Produced Alternative?" The pipes/radiators throughout the building
would be the counterpoise to the hot-wire ... not at all intended as a
ground. I'm poised to do this rather quickly, minus the bandpass
filter, which I need to order from HRO or AES.

So maybe I will try this out... Any last words about safety? Not
blowing up the furnace room and heating oil tank? ;-)

By the way, off topic, but can anyone please get me a good e-mail
address for HRO? All the e-mail addresses on their web site are
inoperable. Go figure. ;-)

Thanks!
Rich
(Please don't reply via e-mail ... dead address)

Rich,
How ever you think of it, the 'steam' pipes are
going to be part of your antenna 'system', they
will have RF on them. Filters may 'help', but they
won't remove the RF from the pipes, and the possibility
for RFI is still going tobe there.
Especially at 100 watts, I seriously doubt if you
have to worry about 'blowing up' the boiler room. I
would be more worried about irrate neighbors...
'Doc

PS - Give it a try. If there are complaints, stop!

If it is an old apartment, the plumbing might be copper all the way to the
ground. In a new one, you might want to check if there is plastic pipe
between you and ground.

Good luck,

Bill, W4WNT

"Rich" wrote in message
om...
Hi all. I'm sitting here trying to figure out how to get on the air!
I'm in a big apartment building ... I have these hot water pipes which
feed radiators on every floor ... I'm on the 11th floor.

I'm thinking that I can throw 100' wire out the window (to radiate)
and ground to the hot water pipes. Thoughts? Any risk of damage to
the heating system? I don't know how the water's heated...

Thanks,
Rich
(Please don't reply via e-mail ... dead address)

In article ,
Rich wrote:

Hi all. Thanks for your replies. To give you more info, I'm only
capable of up to 100w. I'm thinking about adding a Bencher 1.8-30 MHz
Bandpass Filter to my set-up to minimize TV interference (even if I
use a dipole, ref. my other post, " Dipole/Balun? Commercially
Produced Alternative?"

This sort of bandpass filter may not help matters much if at all, for
several reasons:

- If you're using a commercially-built transceiver, it almost
certainly meets the FCC's harmonic-suppression filtering rules right
out of the box - it has the necessary low-pass filters built into
its output section. You _might_ get some additional, useful
suppression via an external filter, but I suspect that the benefit
will be rather minor.

- These days, it's more usual for RFI/TVI to be caused by
"fundamental overload". TV sets usually have wideband tuner
circuitry, and they can be overloaded by strong RF signals outside
of the frequency range to which they're currently tuned. The RF
drives their first stage into saturation, and can wipe out
reception of _all_ channels. This cannot be avoided or treated
with a low-pass filter on the transmitter - it requires a high-pass
filter at the TV set's antenna terminals (and, in some cases, a few
ferrites on the power and speaker wires, to keep RF from leaking
into the set through these paths).

- If you're using pipes/radiators/gutters as part of your antenna or
counterpoise, you have to worry to some extent about the
possibility of rectification at metal-to-metal junctions. This can
cause the generation of harmonics (including some in the TV band)
even if your transmitter's output is perfectly clean. Eliminating
this problem requires finding the corroded metal-to-metal junctions
which are acting as rectifying diodes, and correcting the problem
(either isolating the metals completely, or "bonding" them more
securely with rivets, wire, contact-surface cleaning and
preservation, etc.

The pipes/radiators throughout the building
would be the counterpoise to the hot-wire ... not at all intended as a
ground. I'm poised to do this rather quickly, minus the bandpass
filter, which I need to order from HRO or AES.

Well, it's probably worth a try, but I suspect that the risk of
problems is nontrivial.

So maybe I will try this out... Any last words about safety? Not
blowing up the furnace room and heating oil tank? ;-)

Keep your transmit power relatively low. Fundamental overload and
other RFI/TVI problems seem to be less common at transmitter outputs
below 20 watts.

Just remember that the RF voltages appearing at certain points on your
antenna and "counterpoise" can be quite high, even at moderate power
levels. You may be exposing people to a significant risk of shock or
RF burns. If somebody gets "bitten" when they touch a radiator,
they're likely to be really irate with you.

I'd encourage you to run through the FCC's RF-exposure calculations,
assuming an "uncontrolled" operating environment, and very small
working distances between people and the antenna/counterpoise.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
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