How far away could this have come from?

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dragon48

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I'm new to marine scanning and recently picked up a conversation on 156.45. Somebody was in the process of docking his boat. I am indoors with a stock telescoping antenna.

I'm curious as to how far away from my location this could have been.
 

Jimru

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Hi. Well, being indoors with a stock antenna (rubber duckie if it's a hand held scanner and a short metal telescopic antenna if it's a base model) will for sure limit your reception. It also depends upon terrain (are you high up in the hills, for instance?), output power of the marine radio (were they using a handheld or mobile/installed rig?) and propagation conditions (sometimes a signal can travel very far without a lot of power output if atmospheric conditions are favorable).
How far are you from the nearest harbor?
 

dragon48

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I am basically at sea level - not more than 100 feet higher.

There are a lot of places to dock boats near me. I don't know where the closest harbor is, but certainly not more than 5 miles away.
 

marksmith

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I am basically at sea level - not more than 100 feet higher.

There are a lot of places to dock boats near me. I don't know where the closest harbor is, but certainly not more than 5 miles away.
It's likely that the boat docking was within a mile from you on that frequency given your altitude and proximity to water if it was a clear reception.

I have similar situation with a highway bridge within a mile and can hear every bridge tender vs boat conversation. There is also a marina at the foot of the bridge.

Mark
536/436/ws1095/996p2/996xt/325p2/396xt/psr800/396t/HP-1/HP-2 & others
 

troymail

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So many factors could play into this -- bottom line is you really won't know unless you hear some type of description of the location in the conversation. As was mentioned, atmospherics play a huge role - time of year, time of day, weather/storms in the area, etc. The use could be right outside or sometimes many, many miles from you - particularly if near a body of water.

Luckily (for most of us), this is one of the "fun" aspects of the scanning hobby ... what am I hearing and where is it coming from?
 

edweirdFL

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I hear boats with a similar setup out to about 5 miles. Land stations (Coast Guard, Marinas, Seatow) which may be running higher power with higher antennas I hear from a little farther out, maybe 10 miles.

I'm located on a barrier island, between the inter-coastal waterway and the ocean, so there's maritime activity very close to me. I'm sure I'd hear much more from farther away if my antenna was outside and above roof level.
 

mmckenna

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As others have said, based on your location, probably within a mile or two.

However, a 25 watt permanent installed VHF marine radio with a decent antenna can do some wondrous thinks when Mother Nature is willing to assist. I've got an AIS receiver at one of my sites at work. Basically listens in on the two VHF marine channels that are used by ships for beaconing out their positions. From my site, about 1000 above sea level, 3dB gain antenna, good coax, I get hits from ships over 600 miles out. That is clearly the atmosphere doing it's thing. Works better on digital than voice, but with a good setup, it's possible.
 

Jimru

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I hear boats with a similar setup out to about 5 miles. Land stations (Coast Guard, Marinas, Seatow) which may be running higher power with higher antennas I hear from a little farther out, maybe 10 miles.

I'm located on a barrier island, between the inter-coastal waterway and the ocean, so there's maritime activity very close to me. I'm sure I'd hear much more from farther away if my antenna was outside and above roof level.


If you can get an antenna outside, do it!
 
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