Because of difficult mid-winter shortwave propagation, one of this weekend’s VOA News items will be in MFSK16 (55 wpm), to see if it will provide a more successful text decode than our usual MFSK32 (120 wpm).

Here is the lineup for VOA Radiogram, program 92, 3-4 January 2015 (in MFSK 32 except where noted):
 

  1:44  Program preview
  2:39  Iran expands Internet censorship*
  8:42  North Korea TV ends Russian, Chinese films*
16:40  MFSK16: Spray-on solar panels*
25:46  MFSK32: Closing announcements*
28:14  Bonus mode: Olivia 64-2000

*with image

Please send reception reports to radiogram@voanews.com.

VOA Radiogram transmission schedule
(all days and times UTC):
Sat 0930-1000 5910 kHz
Sat 1600-1630 17860 kHz
Sun 0230-0300 5745 kHz
Sun 1930-2000 15670 kHz
All via the Edward R. Murrow transmitting station in North Carolina.

The Mighty KBC will transmit a minute of MFSK64 Saturday at about 1230 UTC on 6095 kHz and Sunday at about 0130 UTC (Saturday 8:30 pm EST) on 7375 kHz. Both frequencies are via Germany. The content will be the same as last weekend. Reports to Eric: themightykbc@gmail.com .

And as decoded by Chris in New Zealand on 27 December, 1600-1630 UTC, 17860 kHz:

Most listeners in Europe were unable to receive VOA Radiogram last weekend Sunday, 7 December, at 1930 UTC, on 15670 kHz. Mid-winter propagation was the cause. The 15670 kHz transmission was received fairly well in North America. And Chris in New Zealand received 15670 well enough for this MFSK32 image decode …

Let’s hope that 15670 is usable in Europe this weekend.

Here is the lineup for VOA Radiogram, program 89, 13-14 December 2014, all in MFSK32 except where noted …

  1:34  Program preview

  2:43  News about amateur radio and shortwave

  5:20  Citizen scientists track coastal ecosystem*

12:45  Controversy about South China Sea boundaries*

20:18  Russian television channel may be shut down*

27:39  Closing announcements

28:32  Bonus mode of the week: Olivia 32-1000

 *with image

 Please send reception reports to radiogram@voanews.com .

 VOA Radiogram transmission schedule
(all days and times UTC):
Sat 0930-1000 5910 kHz
Sat 1600-1630 17860 kHz
Sun 0230-0300 5745 kHz
Sun 1930-2000 15670 kHz
All via the Edward R. Murrow transmitting station in North Carolina.

The Mighty KBC resumes its minute of MFSK64 Saturday at about 1230 UTC on 6095 kHz, and Sunday at about 0130 UTC (8:30 pm EST) on 7375 kHz. Both frequencies are via Germany. Reports to Eric: themightykbc (at) gmail.com .

The ARRL 10-Meter Contest is this weekend, Saturday 0000 to Sunday 2359 UTC.  Modes are CW and phone (no digital modes). An ARRL 100^th anniversary station will operate during the contest from the Voice of America Amateur Radio Club, K3VOA, using the call W1AW/3.

The International Space Station is planning to transmit slow scan television (SSTV) on 18 and 20 December. Details here. The SSTV mode will be PD180, which can be received with MultiPSK.

Decoding VOA Radiogram content usually involves a patch cord from the radio’s headphone jack to a computer’s microphone jack. This, however, can introduce noise from the computer, or the computer’s power supply, to the radio. A solution is an isolating patch cord, which (after some searching) can be purchased. Or you can build one yourself, using these plans kindly provided by VOA Radiogram listener Al Holt in Florida …

After my first few weeks decoding Radiogram programs I noticed a distinct increase in the background noise level when I connected my computer to the radio, something on the order of 6-9 dB on its S-meter. I thought this might be a detriment to the quality of decoding Radiogram content so I started looking for a solution.

There’s enough electrical noise generated within the case of the computer that when the two units are connected with a common ground (earth) point that noise gets induced into the signal path. Sometimes this can be in the form of 60 Hertz hum, but in this case it was RF noise passing through the receiver to its audio output.  The solution is to isolate the grounds between computer and receiver and this is done with a transformer.

An email message from Kim Andrew Elliott suggested some commercial solutions:

http://www.packetradio.com/catalog/index.php?main_page=product_info&cPath=46&products_id=160&zenid=ket94plgp9q73fim8nt1ik5qf0

http://www.sonicelectronix.com/item_26692_Axxess-AGL3.5.html

http://www.gromaudio.com/store/accessories/noise_filter_-_ground_loop_isolator_with_3_5mm.html

8th item down…

http://www.mixitproducts.com/product_list.php

I happened to have a few old miniature transistor radio transformers so I decided to try making one.  Here’s a view of the completed unit and basic schematic:

I wanted to build it in such a way so it would integrate nicely with my equipment and not have to resort to using a lot of adapters. My radio does not have a separate “line out” so I used the headphone out connector which is 3.5mm stereo otherwise known as 1/8” mini-plug. Essentially it’s a tip-ring-sleeve or “TRS” connector. Since we’re dealing with shortwave and a monaural signal, only one transformer is needed and either left or right channel out of the receiver will do; so you use just one channel, left or right…tip or ring. I’m using the cord & plug side as the input and this plugs into the radio’s “headphone out” jack. For the output side of the box I used a “stereo” 3.5mm jack. I connect a cable from my soundcard’s line-in at the rear of the computer to this jack. This arrangement can be modified as necessary depending on the one’s individual’s needs.

You’ll want to try and use a transformer with a 1:1 turns ratio with an impedance between 600 and 1000 Ohms. I used an old interstage transistor radio transformer I had in my junk box. Unfortunately, I don’t think there’s too many of these still in circulation. Radio Shack used to sell one, PN. 273-1374, they’ve been discontinued but may be in stock in some stores.

The Bourns LM-NP-1001-B1L 600:600 Ohm transformer available from Mouser Electronics looks like a good option, sized at 12.6x17x17.7mm (HxWxL):  http://www.mouser.com/ProductDetail/Bourns/LM-NP-1001-B1L/?qs=ulUe94RKhgtJXLP5iCDxaA%3D%3D

Also, the Tamura TTC-5017 data/voice coupling transformer, available from Digikey, could be used. It’s also 600 Ohm 1:1 and sized at 12x14.5x15mm (HxWxL).

http://www.digikey.com/product-detail/en/TTC-5017/MT7207-ND/674286

I mention Radio Shack mainly because they’re a brick and mortar store here in the U.S. and parts are quickly available although somewhat expensive. For the rest of the project I used RS’ Case PN. 270-1801. I clipped one of the plugs off the cord, PN. 420-080, and wired it directly to the input side of the transformer.   Using a cord gives you a molded-on connector as well as some extra cable for internal wiring. The output jack, PN. 274-249, is wired with both tip and ring connected to the “high” side of the transformer to feed both channels of the soundcard. The “perfboard” I had on-hand but is a trimmed-down section of PN. 276-147.

Radiogram data transmission is pretty noise tolerant but using the audio isolator will help a great deal when  shortwave RF noise level is high by eliminating any additional locally produced noise between computer and receiver.

Happy Decoding!

VOA Radiogram this weekend includes news about a new report on world Internet freedom.

Here is the lineup for VOA Radiogram, program 88, 6-7 December 2014, all in MFSK32 except where indicated:

  1:38  Program preview
  2:41  Audio processor and DX meetings*
  6:51  Internet freedom report*
14:45  Mineral, mostly inaccessible, is named*
18:57  Exhibition of Navajo jewelry*
26:43  Closing announcements*
28:29  Bonus mode: QPSK31

*with image

Please send reception reports to radiogram@voanews.com.

VOA Radiogram transmission schedule
(all days and times UTC):
Sat 0930-1000 5910 kHz
Sat 1600-1630 17860 kHz
Sun 0230-0300 5745 kHz
Sun 1930-2000 15670 kHz
All via the Edward R. Murrow transmitting station in North Carolina.

The Mighty KBC will not transmit the usual minute of MFSK64 this weekend. The MFSK64 will return next weekend.

Klaus, in Germany, specializes in listening to and decoding VOA Radiogram using low-end receivers. On 22 November 2014, he set up for himself a double challenge.

First, he listened on a Wetekom KK-9803 (same as the Ktchibo/Kaide KK-9803) radio costing only 5 Euros.

Here is a picture of Klaus’s KK-9903 feeding a small audio recorder.  Note the Y adapter at the KK-9903’s earphone jack, allowing simultaneous recording and listening. …

Second, Klaus tuned in the transmission at 0930 UTC on 5910 kHz, which, this time of year, is only beginning, faintly, to propagate from North Carolina to Europe.

Despite these obstacles, Klaus was able to decode this serviceable MFSK32 image of the 2014 World Internet Conference Logo …

The MFSK32 decoding had some errors, but was not bad considering the circumstances …