Very interesting post Yuri! I'm going to be forced to respond to
it twice under two separate subject references.
I think the mystery about the behaviour in the tunnel is possibly
less mysterious than it first appears. What I am about to say is
pure conjecture but I'm sure someone in the area (of the tunnels)
can clear up wether I'm guessing correctly or not.
Many places (Baltimore springs to mind) that have long tunnels
with significant traffic in them _and_ local radio stations aimed
at the motoring audience have a system to carry the radio signals
into the tunnel where they would ordinarily not propagate. The
system can be of the "leaky feeder" type or the "micro cellular"
type depending on the exact mechanism used to distribute the
signal in the tunnel. If this system is working, you hear the
signals, if it isn't, you don't.
So, how about it denizens of NYC and environs. Do they have such
systems in the tunnels in question or not?
Somehow, I failed to notice the part of Tom's post that you
quoted when he posted it. But it deserves a response on subject.
Thanks for quoting it.
73, Eric N7CL
>From: K3BU <K3BU@aol.com>
To: <topband@contesting.com>
>Date: Mon, 9 Mar 1998 09:04:51 EST
>
>In a message dated 98-03-08 19:05:39 EST, W8JI writes:
>
>> The 160 meter skin depth (distance where current drops to 37%
>> of the value traveling in the conductor) is about 30 meters in
>> poor soil, ten meters in good soil, and about a foot in salt
>> water. Current effectively goes to zero at about 10 skin
>> depths.
>
>
>BIG Question that has been puzzling me:
>
> When I travel to New York City by car and take either
>Lincoln or Holland tunnel under Hudson river and listen to AM
>radio, usually 770 WABC, on most of the days I can hear radio
>solid S9 throught the tunnel. On few days there is no
>signal. This would happend to other AM stations too, so it is not
>the case of particular station running QRP. Time of the day does
>not seem to matter. The only link I have been able to observe,
>that when this happens, changes in weather follow. HF and FM are
>dead in the tunnel.
> WHY?
>
> Changes to chemistry of water above? Or are we refracting,
>ducting - conducting?
>
>Yuri Blanarovich, VE3BMV, K3BU/m
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