Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 16-02-2015, 18:04   #1
Registered User

Join Date: Jun 2010
Location: Sailing the Caribbean
Boat: Switch 51
Posts: 1,498
Strange Radio Issue

We have a Standard Horizon 2100 with AIS reception that has been great for 4 years. However, recently it has been doing something funky which I have NO IDEA how to diagnose. A few seconds after a transmission by us, we hear our own message again sounding a little faint and scratchy. The recipient doesn't hear it and just talks over it, but it interferes with us hearing them. Any idea what this could be? It has happened over a span of hundreds of miles, so I don't think it is some local phenomena. We have the usual panoply of electronics on when it happens, but they are the same electronics that were on when it was working well in the past. thx
__________________

__________________
SVNeko is offline   Reply With Quote
Old 16-02-2015, 18:18   #2
F51
Registered User

Join Date: Mar 2010
Posts: 235
Images: 5
Re: Strange Radio Issue

Ok, I think you're pulling our leg, but I'll try. Turn off everything electrical/electronic on the boat except the radio. Does it still do it? Then measure exactly how long the delay is. Is the moon above the horizon? Then maybe it is some kind of moon bounce, but the signal would be so low coming back as to be unreadable. Hams use EME moonbounce to communicate, but it takes some pretty sophisticated gear. Let us know what you find.
__________________

__________________
F51 is offline   Reply With Quote
Old 16-02-2015, 18:54   #3
Moderator
 
Paul Elliott's Avatar

Cruisers Forum Supporter

Join Date: Sep 2006
Posts: 3,865
Images: 4
Re: Strange Radio Issue

Zero point zero zero chance of moonbounce!

There are some VHF radios with a "replay last-received message" capability, but not the SH2100 (and this would not fit the problem as described). Moonbounce would give you about a 2.6 second delay, but the losses are so huge that your marine radio gear could *never* pick up the reflection. Sometimes HF signals can propagate around the world and back (giving about a 0.15 second delay), but not VHF.

I am stumped.
__________________
Paul Elliott, S/V VALIS - Pacific Seacraft 44 #16 - Friday Harbor, WA
www.sailvalis.com
Paul Elliott is offline   Reply With Quote
Old 16-02-2015, 19:02   #4
cruiser

Join Date: Feb 2008
Location: North Charleston, SC
Boat: Camano Troll
Posts: 4,669
Re: Strange Radio Issue

Standard Horizon has some of the best customer service in the industry so my suggestion is to call them and talk to them about it.


I'm assuming you're not transmitting on channel 26 or 27 which in some areas have a SeaTow radio check feature that plays back your transmission.
__________________
rwidman is offline   Reply With Quote
Old 16-02-2015, 19:08   #5
Registered User
 
BigJohn's Avatar

Join Date: Mar 2013
Posts: 134
Re: Strange Radio Issue

Quote:
Originally Posted by SVNeko View Post
We have a Standard Horizon 2100 with AIS reception that has been great for 4 years. However, recently it has been doing something funky which I have NO IDEA how to diagnose. A few seconds after a transmission by us, we hear our own message again sounding a little faint and scratchy. The recipient doesn't hear it and just talks over it, but it interferes with us hearing them. Any idea what this could be? It has happened over a span of hundreds of miles, so I don't think it is some local phenomena. We have the usual panoply of electronics on when it happens, but they are the same electronics that were on when it was working well in the past. thx
sounds like you are picking up the harmonic for some strange reason ...

does your Tx have a gain control? if so, try reducing it ...
__________________
BigJohn is offline   Reply With Quote
Old 16-02-2015, 19:39   #6
Registered User
 
S/V Illusion's Avatar

Join Date: Oct 2007
Location: Lakewood Ranch, FLORIDA
Boat: Alden 50, Sarasota, Florida
Posts: 1,693
Re: Strange Radio Issue

A "harmonic" is a radiated signal usually on a multiple of the frequency. It has nothing to do with a delayed transmission. An increase in gain would serve only to distort the audio or increase deviation on FM. Nothing related to the described delay.

Sounds more likely this is either a delusion or a dysfunctional hearing aide.
__________________
S/V Illusion is offline   Reply With Quote
Old 16-02-2015, 19:42   #7
Registered User
 
Tx J's Avatar

Join Date: Jan 2013
Location: South Texas
Boat: Newport 28 & Robalo 20
Posts: 363
Re: Strange Radio Issue

Quote:
Originally Posted by SVNeko View Post
We have a Standard Horizon 2100 with AIS reception that has been great for 4 years. However, recently it has been doing something funky which I have NO IDEA how to diagnose. A few seconds after a transmission by us, we hear our own message again sounding a little faint and scratchy. The recipient doesn't hear it and just talks over it, but it interferes with us hearing them. Any idea what this could be? It has happened over a span of hundreds of miles, so I don't think it is some local phenomena. We have the usual panoply of electronics on when it happens, but they are the same electronics that were on when it was working well in the past. thx

If it were simultaneous crosstalk it might be explicable, but hearing a presumed radio echo "a few seconds after", with RF traveling at close to 186K miles per second (speed of light), kind of rules out any reasonable external factor.

Sounds like the VHF has developed a fault that is mimicking something called an Analog delay line - Wikipedia, the free encyclopedia , which could possibly reproduce your 'delayed' voice transmission in the receiver/audio circuit.

Suggest you plug in another VHF and see if this perceived audio "delay" problem goes away. If it does, somebody, like SH, should be mighty interested in playing around with that VHF unit.

(Have you looked for a UFO overhead at these times? Any faint woo-woo Twilight Zone music in the background? )
__________________
Tx J is offline   Reply With Quote
Old 16-02-2015, 19:49   #8
Registered User
 
Tx J's Avatar

Join Date: Jan 2013
Location: South Texas
Boat: Newport 28 & Robalo 20
Posts: 363
Re: Strange Radio Issue

Quote:
Originally Posted by rwidman View Post
Standard Horizon has some of the best customer service in the industry so my suggestion is to call them and talk to them about it.


I'm assuming you're not transmitting on channel 26 or 27 which in some areas have a SeaTow radio check feature that plays back your transmission.

Certainly plausible, and if the Sea Tow repeater were defective and echoing other channels too. But the OP wouldn't be the only one in the area having this problem.
__________________
Tx J is offline   Reply With Quote
Old 16-02-2015, 20:14   #9
Registered User
 
Tx J's Avatar

Join Date: Jan 2013
Location: South Texas
Boat: Newport 28 & Robalo 20
Posts: 363
Re: Strange Radio Issue

Quote:
Originally Posted by S/V Illusion View Post
A "harmonic" is a radiated signal usually on a multiple of the frequency. It has nothing to do with a delayed transmission. An increase in gain would serve only to distort the audio or increase deviation on FM. Nothing related to the described delay.

Sounds more likely this is either a delusion or a dysfunctional hearing aide.
Exactly, "harmonics" travel at exactly the same speed, contemporaneously with, the fundamental/base frequency transmission; as even multiples of that frequency, subject only to any propagation differences of the (always weaker) higher harmonic being in a different 'band'.
__________________
Tx J is offline   Reply With Quote
Old 17-02-2015, 09:52   #10
Moderator
 
Paul Elliott's Avatar

Cruisers Forum Supporter

Join Date: Sep 2006
Posts: 3,865
Images: 4
Re: Strange Radio Issue

Quote:
Originally Posted by rwidman View Post
I'm assuming you're not transmitting on channel 26 or 27 which in some areas have a SeaTow radio check feature that plays back your transmission.
This is by far the most likely explanation (a SeaTow or similar playback station). I'm embarassed that I didn't think of it, since I've got a friend who operates one of these on channel 28 up here in Friday Harbor.
__________________
Paul Elliott, S/V VALIS - Pacific Seacraft 44 #16 - Friday Harbor, WA
www.sailvalis.com
Paul Elliott is offline   Reply With Quote
Old 17-02-2015, 10:00   #11
Senior Cruiser
 
colemj's Avatar

Cruisers Forum Supporter

Join Date: Oct 2005
Location: Presently on US East Coast
Boat: Manta 40 "Reach"
Posts: 10,049
Images: 12
Re: Strange Radio Issue

Assuming it isn't just a new voice in your head, does it happen only near land? Only on certain channels?

I have no explanation for the following thought, but as a WAG, could it be triggering a 2M repeater somewhere because its tx and rx bandwidths have become way out of spec?

If you key the mic while listening to other (different) channels on a handheld, do you hear any noises?

Mark
__________________
www.svreach.com

You do not need a parachute to skydive. You only need a parachute to skydive twice.
colemj is offline   Reply With Quote
Old 17-02-2015, 13:31   #12
Registered User

Join Date: Jun 2010
Location: Sailing the Caribbean
Boat: Switch 51
Posts: 1,498
Re: Strange Radio Issue

Its happening in the remote islands of Belize. There is hardly any equipment here at all, let alone a SeaTow station. It happens on 14 and 16, but I haven't really tested many channels. At first I thought it only happened when I was monitoring two channels, but that clearly now is not the case. Mark, what's a 2M repeater? And, no, no noises on different channels when the mic is keyed. When keyed on the same channel the closeby handheld squeals of course.
__________________
SVNeko is offline   Reply With Quote
Old 17-02-2015, 13:41   #13
Senior Cruiser
 
colemj's Avatar

Cruisers Forum Supporter

Join Date: Oct 2005
Location: Presently on US East Coast
Boat: Manta 40 "Reach"
Posts: 10,049
Images: 12
Re: Strange Radio Issue

Two meter repeaters are ham stations set up to repeat radio signals to allow for longer distance communications. Two meters also covers the VHF bands, which is why I suggested that your radio may be out of spec.

The whole thing was a WAG, though. It is unlikely there are any 2M repeaters in Belize, or in range of you. Your problem is certainly a new one for me.

You sure it isn't just a new voice in your head?

Mark
__________________
www.svreach.com

You do not need a parachute to skydive. You only need a parachute to skydive twice.
colemj is offline   Reply With Quote
Old 17-02-2015, 15:36   #14
Registered User

Join Date: Jun 2010
Location: Sailing the Caribbean
Boat: Switch 51
Posts: 1,498
Re: Strange Radio Issue

No, not a new voice in my head... and all the old ones are accounted for.

Sent from my SM-T210R using Cruisers Sailing Forum mobile app
__________________
SVNeko is offline   Reply With Quote
Old 18-02-2015, 09:58   #15
Registered User
 
gilgsn's Avatar

Join Date: Jul 2014
Location: Florida
Boat: Morris Frances 26
Posts: 158
Re: Strange Radio Issue

Ham repeaters "repeat" signals instantly and most require a tone to trigger them; no way. The simplest explanation would be that the signal is repeated by some automated system within range. Why? No idea. I doubt a hardware problem could do this, and the signal bouncing on something with such a long delay is very unlikely..

Gil


Sent from my iPhone using Tapatalk
__________________

__________________
gilgsn is online now   Reply With Quote
Reply

Tags
radio

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

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 Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
strange nmea 183 out issue raymarine e125 smac999 Marine Electronics 8 06-09-2013 14:22
VHF Radio Issue Lyn Hancox Marine Electronics 2 27-12-2011 10:10
VHF Radio Transmit Issue claddaghcan Marine Electronics 4 23-04-2010 11:46
XM Radio & Sirius Radio cchris0411 Fishing, Recreation & Fun 25 13-03-2007 02:10



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 00:41.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.