VOA To Test Digital Modes

[n1kgh]

I heard most of the modes on 5745 kHz during the Sunday night UTC broadcast. If anyone with a portable could decode MFSK-4, my hat's off to them.

This is what I sent to Kim:
MFSK-4 1500 Hz: Partial decode at 1499 Hz
MFSK16 1500 Hz: Good decode of radio telescope news item
MFSK32 1000 Hz: Good decode, some garble
MFSK32 2500 Hz: Almost perfect copy
PSKR125 2500 Hz: Good decode, some garble
PSKR250 2500 Hz: Good decode, some garble.
MFSK64 2500 Hz: Nearly perfect copy
MFSK64 2500 Hz: Flmsg format: perfect copy with HTML
PSKR500 2000 Hz: Fair copy, considerable garble, drone news item
MFSK32 2000 Hz: Picture of drone received, some slight noise
MFSK32 1500 Hz: VOA Radiogram logo noisy but legible

I am using a Funcube Dongle Pro Plus (with HF coverage) connected to a Windows laptop running SDR-Radio and a cheap Radio Shack active antenna in my apartment window.

It wasn't exactly armchair copy, but I did get S7 signals, more or less.
I'm certain I would have decoded the MFSK64 signals with my DX-398; they came through with the best quality.

 

[Darth_vader]

"With a recent change in the VOA charter, they can now broadcast to us legally. They are, in fact, doing it now via Internet streaming on the Pure Connect website, and no doubt others."

Really? When did that happen/take effect?

Great to know that. I used to listen to VOA all the time as a kid out of the Delano site. Where I was/still am in Washington, I often times didn't even need to put up the aerial on my radio. What are the chances of them reactivating that transmitter site in light of the change?

(The charter, if it's the one I'm thinking of, was the "Smith Mundt Act".)

 

[ka3jjz]

Yes, Anakin, You're right about the charter name :.>>

The next digital tests, from DXLD and the NASWA list;

VOA Radiogram for the weekend of 6 and 7 April 2013 will feature MT63 modes, comparing them to MFSK modes at similar speeds. Details here:

http://voaradiogram.net/post/47107850354/voa-radiogram-on-6-7-april-will-feature-mt63-modes

Also digital text this weekend from the Mighty KBC and from PCJ via WRMI. And daily from Radio 700 Kurzwelledienst in Germany. More information:

http://voaradiogram.net/post/47198906846/more-shortwave-broadcasters-experimenting-with-digital

Mike

 

[Darth_vader]

So, anyways, when did they finally relax Smith-Mundt?

I recall hearing some talk about it several years back, concerning a somewhat controversial documentary VOA had produced regarding (I think) opium production in the Middle East and should they be allowed to make the programme available domestically, but I didn't think anything had become of it since that was about all I'd heard.

 

[ka3jjz]

Here are the next 2 scheduled tests, using Olivia this time (via the DXLD Yahoo group)

VOA Radiogram

VOA Radiogram

Note that the recent Class M6.5 flare is, as I write this, expected to start to hit the ionosphere today, so propagation is going to be goofy for the next day or two at least

Mike

 

[ka3jjz]

The next set of tests:

VOA Radiogram will feature Thor digital text modes this weekend, with
MFSK modes also transmitted for comparison. Details here:

http://voaradiogram.net/post/48358773399/voa-radiogram-april-20-21-will-feature-thor-modes

The Mighty KBC will also compare Thor and KBC with a simultaneous transmission. More information:

VOA Radiogram

Most interesting re the last sets of spam that has been removed - from China, no less...

Mike

 

[ka3jjz]

Sorry I didn't get this sooner, but I've been very busy all day - perhaps you can get this via a repeat broadcast (via DXLD)...

VOA Radiogram this weekend includes a VOA news story in Flamp format. It's sent twice, with the second transmission filling in any content missed in the first due to fades. Or at least that's the plan.
Information here:

VOA Radiogram

The Mighty KBC North America broadcast, Sunday 0000-0200 UTC on 7375 kHz will include Thor 50x2 and MFSK32 modes:

VOA Radiogram

 

[ka3jjz]

Here is the next set of broadcasts, via DXLD. Notice that they are now going to start testing using SSTV, a mode used by hams to broadcast images.

For the VOA Radiogram program on May 18 and 19, we will continue to experiment with images. In fact, we will transmit the same picture three ways: in two SSTV modes and then as an MFSK32 image. Bring something to read, or an electronics project, because these picture transmissions will take 4 to 5 minutes each.

To decode the SSTV modes, several software programs are available. They include the RX-SSTV (receive only), , MMSSTV, and Digital Master 780, part of the Ham Radio Deluxe suite.

Before the images will be two VOA news stories in MFSK32 text, with the usual center audio frequency of 1500 Hz. The second story is in French, as we continue to determine if accented letters appear correctly on your display.

To view accented characters in Fldigi: Configure > Colors & Fonts > next to Select Char Set, select UTF-8. To keep your selection of UTF-8, under Configuration, click Save Config.

Here is the lineup for VOA Radiogram the weekend on 18 and 19 May:

2:55 MFSK16 Program preview
1:59 MFSK32 VOA News in English
4:03 MFSK32 VOA News in French
1:07 MFSK16 Intro to SSTV transmissions
4:31 Scottie DX SSTV
:10 Tone (to give you time to save your Scottie DX image)
5:08 Pasokon P5 SSTV
:25 MFSK16 intro to MFSK32 image
4:07 MFSK32 image
1:10 MFSK16 closing announcements
1:22 Surprise mode of the week (mixes somewhat with the closing music)

On VOA Radiogram during the weekend of 25-26 May, we will experiment with the Easypal digital SSTV mode, comparing it to MFSK32. Easypal images are transmitted by radio amateurs on 14233 kHz.

VOA Radiogram transmission schedule
(all days and times UTC)
Sat 1600-1630 17860 kHz
Sun 0230-0300 5745 kHz
Sun 1300-1330 6095 kHz
Sun 1930-2000 15670 kHz
All via the Edward R. Murrow transmitting station in North Carolina.

This weekend, there will also be digital transmissions from Radio Australia and The Mighty KBC

 

[ka3jjz]

For those of you that are MAC/Linux users and want to try your hand at the SSTV decoding, here are two possibilities

MultiMode - CW RTTY SSTV FAX MORSE PSK31 ACARS SITOR AMTOR ALE DTMF FFT ASCII Decoding Software for the Macintosh

index.html

Mike

 

[ka3jjz]

Here's the latest test, using EasyPal this time

VOA Radiogram

As I understand it there will be no R Australia tests this weekend

Mike

 

[n0nhp]

Worked pretty well for the Korean train, can't get enough blocks for the cicada.

Bruce

 

[ka3jjz]

As a reminder, please send all reports - along with the image you copied - to Dr.Kim Andrew Elliott at the address shown in the blog

And don't forget to mention that you read about it at RadioReference (free plug there)...

Mike

 

[n0nhp]

Kim gets the full reports, I just thought the picture was worth posting.

Bruce

 

[ka3jjz]

Here are some comments from last week's test, and this week's schedule, which includes another EasyPal transmission

VOA Radiogram

Mike

 

[ka3jjz]

Here is this weekend's test schedule for the VOA and KBC (via the NASWA Yahoo group)

VOA Radiogram

VOA Radiogram

Mike

 

[ka3jjz]

The next set of tests involve inserting noise on top of the digital signal...

VOA Radiogram

And...
The Mighty KBC, via Germany, UTC Sunday 0000-0200 on 9925 kHz, will transmit MFSK32 text at about 0136 and an MFSK32 image at just before 0200, both centered on 1500 Hz.

both of these courtesy of the DXLD Yahoo group...Mike

 

[ka3jjz]

Via DXLD - the next set of tests

VOA Radiogram

and a primer on what is needed to decode the transmissions

VOA Radiogram

Just to add to what Kim wrote - although he gives the URL for FLDigi in the above article, he doesn't give the links for the other packages he mentions, namely

MixW
MultiPSK
DM780 (part of Ham Radio Deluxe)

Both MixW and MultiPSK can be located from links on the page in my sig. Ham Radio Deluxe's URL is given.

However there are likely other apps that can copy MFSK transmissions. If you know of any please share the link. I can pass it along.

Mike