READ THIS BEFORE POSTING, what this board is, and getting the most out of it

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This board is about identifying mystery or unknown modes heard in the HF spectrum.  If you don’t know what a signal is there is a good chance that others might know, or at least be able to take a good guess.  As signals are identified here they will be added to the HF Signals Identification Wiki here (  http://www.hfunderground.com/wiki/Signal_Identification  ) on HFU (if they are not already on it).

The purpose of this board is not to ID unknown transmission, but rather the mode of a transmission.  That means those odd noises you always wondered about as you tuned across the bands.  If you hear an unknown SSB net or unknown ALE net and want to know who it is or where it is from it should not be addressed here, the mode of those transmissions are already known, and there are other boards on HFU to ask such questions.  However, if you hear a signal that you cannot identify the mode of, and it turns out to be ALE, this is the perfect place for that.  There will be some overlap here, but let’s try to stay with unknown modes as much as possible.

Not everyone has the same level of exposure in a hobby such as this, so it is understandable, in fact inevitable, that occasionally someone will ask about a mode that has already been covered or seems very basic.  So what?  As long as the person asking the question goes away with more information than they started with, it is all good.

Keep in mind that the folks answering here typically are not professionals and might not know either, so if you get no answer that does not mean you are being ignored.  Sometimes unknown stays unknown, but that does not mean a discussion about it does not shed at least a little light on it.  And a lot of people only check these boards every once in a while, so your question might not be answered right away.

What should be in a post?

Without certain basic data a mode cannot be identified.  The more data you can include in your post the more likely the mode is to be correctly identified.  For example, asking a vague question like “I heard a clicking noise in the 8 MHz band, what is it?” will probably not result in a meaningful answer.

The minimum information presented with a question should be:

1.  Frequency (kHz)
2.  Time (UTC)
3.  Duration
4.  Receiver Mode
5.  Receiver Location
6.  Description.

1.  Frequency of the signal, preferably in kHz.  Be as precise as you can be here, sometimes one or two kHz can be the difference between a proper ID and a false ID.

2.  Time of the reception, in UTC.  Radio reports are almost universally done in UTC or GMT anyway, it avoids confusion.  If you post it in your local time then whoever wants to answer has to convert to UTC to get an idea of when it was, and they may not know your location or the proper time offset for your location.

3.  Duration of the transmission.  Was this a signal that stayed on constantly?  Or did it come and go in short bursts?

4.  Receiver mode you were using when you heard the signal.  Sometimes when people do not know what a signal is they use an incorrect mode to try and listen to it.  A signal will often sound different depending on what mode you use to listen to it.

5.  Location of receiver.  This does not have to be exact information, but signals that might be heard on 8000 kHz at 2300 UTC on the west coast of the US are a little different than the ones that might be heard at the same time in Jalalabad.  If you are using a remote receiver than your location is not the one that counts, but rather the location of the receiver is what needs to be known.

6.  Your description of what you heard.  What did it sound like?  What do you think it might be?  Even if you don’t know what it is it can’t hurt for you to say what it sounded like.



In addition to the above minimums there is additional information that can increase the likelihood of a correct identification.

If using a local radio, what is your receiver and antenna?

It is very desirable for you to include a link to a video or audio recording of the signal in question.  Including a recording increases the chances of a correct identification significantly, I cannot stress enough how helpful to ID this is.  If you are unsure what receiver mode to record the audio in, try a couple of them.  Unfortunately it is not always possible to make such a recording.

A picture of the transmission goes a long way.  If you are using an SDR a screen shot of the waterfall display is a big help.  If you are using a traditional receiver a screen shot of the audio fed into some kind of spectral display software, like Argo, fldigi, SpectroGram16, etc, is a good thing.