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rockDAWG 03-13-2013 01:12 PM

Weatherfax audio file for testing
 
Anyone have a link for an audio file to test my iPhone App?

I have this
HF Weather Fax Marine Radiofascimile Decoder App

TIA :)

RichH 03-13-2013 01:51 PM

Re: Weatherfax audio file for testing
 
That's an iPAD app, are you sure it will work with an iPHONE?

There are quite a few ONLINE HF/SSB radios that can be controlled and set to the frequencies you want to listen to.
Simply follow the internet radio's 'how to tune' and listen ... and set your iPhone near the computer speaker (best to use an amplified PC speaker). Your computer connected to one of these 'online' and controllable radio's will then 'substitute' as an HF/SSB radio.

Here's an example of one based in Virgina: http://www.chilton.com/scripts/radio/R8-receiver

Others (but choose the right frequency range and best/close location): The Listening Post - Links to Other Radios

Here's your NOAA WeFax schedules. Use Boston @ 9.110 MHz in AM mode.
NWS Radiofax
Most WeFAX is broadcast on AM mode, not LowerSideBand or UpperSideBand modes, so set the internet radio's controls to AM for proper connection.

If using an internet controlled radio via your PC choose/select an internet based receiver that is 'fairly close' (~500 mi) to the broadcast station

General NOAA listing for broadcast marine weather, etc. : National Weather Service Marine Forecasts

SVAuspicious 03-13-2013 05:54 PM

Re: Weatherfax audio file for testing
 
The iDevice software works but is not much more than a toy. Since there is no way to connect directly to the radio you have to have the audio up which is irritating and best and keeps the off watch awake for hours at worst.

Wefax is transmitted as FSK. Most mariners receive it using SSB (usually USB) which is why the seminal reference rfax.pdf reminds you to offset the tuning frequency by 1900 Hz. If you use LSB you'll need software that can invert the tones.

smurphny 03-13-2013 06:59 PM

Re: Weatherfax audio file for testing
 
Looks like a great app if it works. SSB analog speaker tones are usable to access Wfax. In fact, with a cheap HF radio and some software, you can get Wfax onto a computer. I haven't tried this and can't comment on its relative usefulness but would suspect it would be prone to interference and loss of signal. I wonder if they're filtering signals and repeating on 4g networks to get a reliable picture. It's easy to spend 3k on a good SSB/Pactor system. Can't imagine you'd be able to come anywhere close to the long distance reliability with an iphone...yet. I can pick up fax signals from afar on the SSB. This kind of radio circuitry can't possibly be in an iphone.

tombesore 03-13-2013 07:14 PM

Re: Weatherfax audio file for testing
 
Here's a link to the current schedule of WeatherFax transmissions by the Coast Guard.

http://www.nws.noaa.gov/om/marine/rfax.pdf

Set your dial frequency to 1.9KHz below the stated frequencies and keep the radio on USB. You can get this signal from a simple Grundig handheld radio with a nice long wire antenna and feed the speaker output right into your iDevice.


If you don't have access to a radio, I am open to experimenting via Skype or Google+ with you if you'd like me to tune my receiver to these frequencies and feed you the audio remotely. It could be a cool group demonstration on a G+ Hangout.

I've experimented with these transmissions and it's really hit or miss depending on the time of day, frequency selection and daily noise level. It makes for an interesting experiment, but I prefer to get my weather by voice broadcast, satellite or even HF email. It's not so frustrating as when the signal starts to fade on your wefax picture!

RichH 03-13-2013 09:38 PM

Re: Weatherfax audio file for testing
 
Quote:

Originally Posted by SVAuspicious (Post 1002200)
Wefax is transmitted as FSK. Most mariners receive it using SSB (usually USB) which is why the seminal reference rfax.pdf reminds you to offset the tuning frequency by 1900 Hz. If you use LSB you'll need software that can invert the tones.

Oops sorry, dame bramage ... indeed most WeFax is broadcast on Upper Side Band (FSK).

Here's the 'mother of all WeFax' websites on the net, including discussions on smart phones, tablets, etc. etc. History

Using a simple audio patch cord between the radio (simple portable 'Short Wave' with AM/USB/LSB/CW or HF/SSB) and a PC and using simple/fairly inexpensive programs will get you WeFax out at sea. I use a simple audio patch from my SSB (or portable SW receiver) into a Mac using "multi-mode" as the software for WeFax and marine TTY - MultiMode - CW RTTY SSTV FAX MORSE PSK31 ACARS SITOR AMTOR ALE DTMF FFT ASCII Decoding Software for the Macintosh

SVAuspicious 03-14-2013 08:16 AM

Re: Weatherfax audio file for testing
 
Quote:

Originally Posted by RichH (Post 1002295)
Oops sorry, dame bramage ... indeed most WeFax is broadcast on Upper Side Band (FSK).

I seem to be on a bit of a tear on vocabulary. Please forgive me. Skip the next paragraph if you don't care about what makes your radio work.

Frequency shift keying (FSK) is generated by a transmitter switching between two very close frequencies, usually 170 or 200 Hz apart, that are called 'mark' and 'space.' It was initially used for radio teletype (RTTY). Some genius (literally) applied to to image transmission and reception by setting standards for keying rates. It was intended to be received in a radio by injecting a signal at the frequency between mark and space and filtering the products with low pass and high pass filters to recover the mark and space. Another genius realized that this was analogous to SSB reception and that a couple of very narrow filters could recover the mark and space. Using an SSB mode (usually upper sideband, USB) means tuning off a bit (1900 Hz) in order to put the mark and space tones in the bandpass of the filters.

But you guys already knew that. *grin* It's pretty cool stuff, actually very simple and robust. Engineering elegance. I wish I knew the names of the geniuses because they deserve to be recognized.

Quote:

Originally Posted by RichH (Post 1002295)
Using a simple audio patch cord between the radio (simple portable 'Short Wave' with AM/USB/LSB/CW or HF/SSB) and a PC and using simple/fairly inexpensive programs will get you WeFax out at sea. I use a simple audio patch from my SSB (or portable SW receiver) into a Mac using "multi-mode" as the software for WeFax and marine TTY - MultiMode - CW RTTY SSTV FAX MORSE PSK31 ACARS SITOR AMTOR ALE DTMF FFT ASCII Decoding Software for the Macintosh

Right. A couple of points. One is that the mic input on MOST laptops is mono and the behavior of stereo plugs in mono jacks isn't always what is expected. Similarly, the way that mono signals (like SSB) are routed to stereo jacks as found on many shortwave radios is not consistent. I strongly suggest a 1/8" male mono plug to 1/8" male mono plug patch cord and a 1/8" female mono jack to 1/8" male stereo plug adapter. Put the adapter in the shortwave radio and hook up the patch cord.

There are a number of software options for Windows: JVCOMM32, Multipsk, and Digipan among others. I usually use JVCOMM32 on delivery. It is simpler and easier to set up. I do use Multipsk on Auspicious as it gives me the ability to transmit radiofax as well as receive.

tombesore 03-14-2013 10:50 AM

Re: Weatherfax audio file for testing
 
You inspired me to do my own little test this morning. I found that I was receiving solid signals (S9+20db) from the 4Kilowatt NMG New Orleans Coast Guard transmitters during their morning run of WEFAX transmissions. The image below was received through a modern HF amateur radio transceiver and fed into the Multimode for Mac program. The frequency was 8502 kHz USB.

As you can see, the image is fair at best, even with a very solid S9 signal and modern reception gear. This is typical of the images I've been able to pull in. The pics are fair at best and most of the time I can barely make out the notations.

Has anyone else had better luck pulling in higher quality pictures over HF? Let's see what you got!

By the way, I also set my iPad next to the speaker with that BlackCat Wefax program running and, while the same image did appear on the iPad, it was far worse quality!

<a href="http://www.flickr.com/photos/besore/8556492357/" title="WEFAX Image by @tombesore, on Flickr"><img src="http://farm9.staticflickr.com/8095/8556492357_5c32acae36.jpg" width="500" height="260" alt="WEFAX Image"></a>

tombesore 03-14-2013 12:25 PM

Re: Weatherfax audio file for testing
 
rockDAWG,

Here's a link to a sample audio file. It's a 24 Hour Surface Forecast WEFAX image transmitted by the US Coast Guard transmitters NMG on 8502kHz this morning around 7:30am central time. With this seemingly strong audio, my decode was readable but only marginal quality.

https://archive.org/download/WEFAXFi...20File%201.wav

RichH 03-14-2013 02:21 PM

Re: Weatherfax audio file for testing
 
Quote:

Originally Posted by tombesore (Post 1002471)
You inspired me to do my own little test this morning. I found that I was receiving solid signals (S9+20db) from the 4Kilowatt NMG New Orleans Coast Guard transmitters during their morning run of WEFAX transmissions. The image below was received through a modern HF amateur radio transceiver and fed into the Multimode for Mac program. The frequency was 8502 kHz USB.

As you can see, the image is fair at best, even with a very solid S9 signal and modern reception gear. This is typical of the images I've been able to pull in. The pics are fair at best and most of the time I can barely make out the notations.

Has anyone else had better luck pulling in higher quality pictures over HF? Let's see what you got!

By the way, I also set my iPad next to the speaker with that BlackCat Wefax program running and, while the same image did appear on the iPad, it was far worse quality!

<a href="http://www.flickr.com/photos/besore/8556492357/" title="WEFAX Image by @tombesore, on Flickr"><img src="http://farm9.staticflickr.com/8095/8556492357_5c32acae36.jpg" width="500" height="260" alt="WEFAX Image"></a>

with Multimode (Cocoa) adjust your radio squelch and output volume (horizontal 'slider' on the top right of the Multimode window) to clarify and adjust such pics., using the 'slider' and your radios fine tune frequency control to maximize the received 'peak' wave forms overlayed and centered to one of the 'red' reference lines in that 'box' at the top right in the multimode window.
Also be sure that youre set up for "line" instead lf 'grey"; "LINE" function is for line charts, "grey" is for satellite pics.

Also be aware that the current sunspot activity is nearing its maximum .... lots of good propagation but can have lots of distortion 'background noise' which can distort your reception.


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