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MarkJ · 18-02-2015, 10:24

I would suggest you try dropping to Low Power and see if it still happens.
If it does then it could be a local problem where you are close to a translator. You are bleeding through onto the translators transmitting frequency.

No that duplex channels ate not used as much some are being put into translator service. They produce a beep at the end of the transmission.

You could check if you have a second receiver (handheld etc) Tx on one and run through the duplex chanels on the other.

Or ring the CIA and complain!

rwidman · 18-02-2015, 12:33

Quote:

Originally Posted by SVNeko

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..

Troubleshooting 101 would suggest that you test all the channels. Also test at normal and low power when that option is available. Just to be sure, test at different times of day. Get a good estimate of the time delay between the transmission and receiving it back. If you have a second radio, make the same tests on it and note the results. If there are any differences in your results, write down the details so you can report them to Standard Horizon (or here).

belizesailor · 18-02-2015, 18:15

Quote:

Originally Posted by SVNeko

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.

There are a few repeaters, or used to be, in Belize/Guate. So that could be a remote possiblilty, but my first guess would be some kind of hardware issue. Would be worthwhile to test another radio in the same area and see if you get the same echo.

ryon · 18-02-2015, 18:51

My first guess was moonbounce. Three seconds delay would be about right. But unless you are have a pretty sophisticated antenna and tracking system on that boat, I kinda doubt it.

Then I thought Bermuda Triangle! You're pretty far away from that, unless there's maybe a space-time resonance at work here that we don't completely understand.

Speaking of things we don't understand, it could be some NSA intelligence collection project, but why would they target YOU, and why wouldn't they relay it over a satellite, or secure cable? Maybe they're messing with you. What are you doing in Belize, anyway?

Now, I'm thinking that something's just haywire in your DSP circuitry.

DeepFrz · 18-02-2015, 19:09

Does an increase in squelch make any difference? Any new electronics installed on board about the time this started happening? Any new apps that could be causing this? There are some apps that can turn a cell into a remote, could this be a possibility? Are you calling the same station when this happens?

Ziggy · 18-02-2015, 19:20

Quote:

Originally Posted by SVNeko

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

The fact that the "echo" sounds "faint and scratchy" suggests to me that the cause is internal to your radio. The reason is that VHF communications are frequency modulated (FM) so any signal attenuation would not result in reduced volume. I suggest contacting Standard Horizon customer support.

You could also try one or more of the duplex channels (e.g., 24-28) and see if you get the same effect. The duplex channels transmit frequency is different from the receive frequency, so if you hear an "echo" it's almost certainly internal.

Ziggy · 19-02-2015, 04:51

A couple more questions: does the problem occur only when communicating with one particular station? Do you also hear an "echo" when nobody responds?

rwidman · 19-02-2015, 06:10

Unless this radio has the feature of replaying a received message (fairly new in the industry), there is no component or set of components inside the radio that could possibly store a transmission and then replay it.

My original suggestion was to contact the manufacturer and describe the issue. I also gave some additional trouble shooting suggestions.

It is not a "harmonic". It is not a cell phone. A second receiver would play the transmission at the same time it was made and the result would be a feedback squeal in the receiver was close enough and turned up loud enough. A SeaTow repeater cannot become defective and start repeating multiple channels.

SVNeko · 19-02-2015, 06:34

Thanks for all the replies. I will do a little more testing today and report back. In the meantime, the manufacturer replied that they had never heard of the issue and suggested a reset of the radio. I was not aware that a radio could be reset but have tried that and will test it also.

SVNeko · 25-02-2015, 12:42

OK, so here's an update on the weird radio issue. No new electronics, apps, etc. The manufacturer (Yaesu) had never heard of the issue before and suggested resetting the radio (who knew a radio had a reset?). Hold down several buttons for a few seconds and let the radio restart. I thought that fixed it because I could not replicate the issue. HOWEVER, on a passage from Belize to Mexico between the Chinchorro Bank and the mainland (where there is nothing), it happened again. This time, though, the other person heard it as well as us and we heard his echo as well as ours. So both radios heard echos from both radios. Before it was just us hearing our echo without the other person hearing. Now, I am beginning to think some of you paranoids might be right.

ka4wja · 25-02-2015, 20:04

Neko,
I'm sorry I missed this thread earlier....'cause I have the answer for you!

What you have experienced is called LDE, or Long Delayed Echoes....
(and NO this is NOT Moonbounce....and I have actually designed/built/used my own 144mhz moonbounce/EME station back in the 1980's, and have made many random contacts on 2m EME over the years....the storms of 2004/2005 destroyed my antennas though!)

Now what are LDE's, you ask....
Well, I won't bore you with all the details, but if you want to know there have been many papers written about them for many many decades now....(I first read about them more than 35 years ago!)....
I think the first observation of them dates back to the 1920's!!
EDIT: first observed in 1927!!!

Quote:

Originally Posted by SVNeko

OK, so here's an update on the weird radio issue. No new electronics, apps, etc. The manufacturer (Yaesu) had never heard of the issue before and suggested resetting the radio (who knew a radio had a reset?). Hold down several buttons for a few seconds and let the radio restart. I thought that fixed it because I could not replicate the issue. HOWEVER, on a passage from Belize to Mexico between the Chinchorro Bank and the mainland (where there is nothing), it happened again. This time, though, the other person heard it as well as us and we heard his echo as well as ours. So both radios heard echos from both radios. Before it was just us hearing our echo without the other person hearing. Now, I am beginning to think some of you paranoids might be right.

Neko, consider yourself a rare / lucky guy!
As I've been in radio comms for > 40 years, and I've never experienced LDE's....(normal echoes and normal delayed echoes, yes....100's and 100's of times....but not LDE's)

I pulled a few references here for you to read....

http://www.df5ai.net/ArticlesDL/LEchoes(E).pdf

Long-Delayed Echoes - Radio Society of Great Britain - Main Site : Radio Society of Great Britain – Main Site

LA3ZA Amateur Radio Blog: More long delayed echoes

What is a Long Delayed Echo?

Mystical delayed radio signals received in Oslo in 1927

Articles on Long-Delayed Radio Echoes

Long Delayes Echoes - Propagation: Long-Delayed Echoes

Surfinâ€™: An Extremely Long Delayed Echo

I hope this clears things up!

Fair winds...

John

ryon · 26-02-2015, 17:00

I think ka4wja has it identified. Interesting links! What they say is "we don't really know." What's it like to be part of a real mystery that science hasn't been able to solve, SVNeko?

belizesailor · 26-02-2015, 18:22

I like this LDE theory:

Cosmic Repeater Hypothesis

Proposed in 1971 by researchers from Stanford University.

A probe sent from an extraterrestrial civilization might be in orbit around us, looking for electromagnetic signals.

Upon finding a signal, and having no way to (necessarily) decode it, the probe might simply re-transmit the signal received.

Seen any strange lights in the sky Neko?

;-)

SVNeko · 01-03-2015, 06:49

Wow, glad to have this solved, even if it is in the style of "In Search Of" (RIP Leonard Nimoy). Also glad to know its not a problem with our radio. Since this is a theory, we'll keep this thread updated as to future developments.