RadioReference on Facebook   RadioReference on Twitter   RadioReference Blog
 

Go Back   The RadioReference.com Forums > Service Specific Monitoring > Marine Monitoring Forum


Marine Monitoring Forum - This is the place to discuss monitoring marine communications

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1 (permalink)  
Old 10-29-2017, 2:00 AM
Member
   
Join Date: Apr 2014
Location: New York N.Y.
Posts: 162
Default How far away could this have come from?

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.
Reply With Quote
Sponsored links
  #2 (permalink)  
Old 10-29-2017, 2:21 AM
Jimru's Avatar
Member
  Premium Subscriber
Premium Subscriber
Amateur Radio Operator
Amateur Radio
 
Join Date: Dec 2002
Location: Henrico County, VA
Posts: 1,284
Default How far away could this have come from?

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?
__________________
Addicted to all things radio for nearly 50 years, and proud of it!
Reply With Quote
  #3 (permalink)  
Old 10-29-2017, 2:48 AM
Member
   
Join Date: Apr 2014
Location: New York N.Y.
Posts: 162
Default

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.
Reply With Quote
  #4 (permalink)  
Old 10-29-2017, 10:32 AM
marksmith's Avatar
Member
   
Join Date: Jun 2007
Location: Anne Arundel County, MD
Posts: 3,685
Default

Quote:
Originally Posted by dragon48 View Post
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
Reply With Quote
  #5 (permalink)  
Old 10-29-2017, 11:34 AM
troymail's Avatar
Member
   
Join Date: Dec 2002
Location: Supply, NC
Posts: 7,184
Default

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?
__________________
Unication G5(UHF)
TRX-2,TRX-1,WS1098,1088x2,1095,1080, PSR800x2,500,PRO96
BCD536,436,396T,BC296D,245XLT,600XLT,IV,VX-8R,MD-390
Reply With Quote
Sponsored links
  #6 (permalink)  
Old 10-29-2017, 2:22 PM
edweirdFL's Avatar
Member
  Premium Subscriber
Premium Subscriber
Amateur Radio Operator
Amateur Radio
 
Join Date: Dec 2004
Location: Daytona Beach, FL
Posts: 259
Default

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.
__________________
TX/RX = IC-T7H IC-7300 IC-7100 FT-817ND
RX = BCD996T Pro-96 Pro-97 OS535(2) R7100 Pro-90 AR8000
Reply With Quote
  #7 (permalink)  
Old 10-29-2017, 3:56 PM
mmckenna's Avatar
Member
   
Join Date: Jul 2005
Location: WTVLCA01DS0
Posts: 7,604
Default

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.
Reply With Quote
  #8 (permalink)  
Old 11-10-2017, 11:39 AM
Jimru's Avatar
Member
  Premium Subscriber
Premium Subscriber
Amateur Radio Operator
Amateur Radio
 
Join Date: Dec 2002
Location: Henrico County, VA
Posts: 1,284
Default

Quote:
Originally Posted by edweirdFL View Post
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!
__________________
Addicted to all things radio for nearly 50 years, and proud of it!
Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -5. The time now is 8:00 AM.


Powered by vBulletin® Version 3.8.2
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
All information here is Copyright 2012 by RadioReference.com LLC and Lindsay C. Blanton III.Ad Management by RedTyger
Copyright 2015 by RadioReference.com LLC Privacy Policy  |  Terms and Conditions