Category Archives: Shortwave Radio

Icom IC-R72: a repair story

Icom-IC-R72-Front-Mehdi-Asgari In this post I’m going to tell you how I repaired my Icom IC-R72 receiver. Although it’s about a specific device, the logic and methodology applies to all radios.

I bought an Icom R72 from a friend for about $200. At first, I just checked 7.0MHZ (40 meter band) and 21.0MHZ (15 meter band) and it was OK. After some time, I tried to listen to some ham radio on 20 meters (14.0MHZ) and it was deaf! I checked everything: antenna connectors, balun…everything.

With some trial and error, I found out that it was deaf from 11-15 MHz. With the help of the members of “Icom R72” Yahoo Group, I found one of the usual suspects: bandpass filters’ switching diodes.

I took a look at the service manual and apparently this radio uses multiple bandpass filters for different frequency ranges.

Schematic-Icom-R72-1

As you see in the above picture (grabbed from service manual), one of the bandpass filters is for 11-15 MHz range–that’s the range where my radio was deaf.

Note that there are multiple ways to test that a radio is deaf at a frequency. One of the simplest ways: connect an antenna or even a long wire to the antenna socket of radio. The noise level should increase; if not, there’s a problem.

Schematic-Icom-R72-2

After testing diodes with a multimeter, I found out that D31 is faulty. Almost all multimeters have a diode-test functionality.

I replaced it. The original diode was 1SS53, but I used a 1N4148 which is very common and found everywhere. Now I have a working radio! 🙂

If you have a radio that’s deaf at a frequency range, there is probably a problem in bandpass filters.

Here are some internal pictures of my Icom IC-R72:

IC-R72-Internal-IF-Stage-Mehdi IC-R72-Board-1 IC-R72-Board-2 Icom-IC-R72-Open

I should thank my friend and electronics mentor, Saeed (EP2LSH) who always helps me in my electronics adventures.

Mehdi Asgari, the author of this post, is a regular contributor to the SWLing Post. Mehdi lives in Tehran and is an active member of the EP2C amateur radio club.

1989 RCI Christmas Special: a studio recording

December 24: Tune in NDR’s annual Christmas greetings program on shortwave

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Many thanks to SWLing Post reader, Harald Kuhl, who writes:

As in past years, German broadcaster NDR will transmit its domestic Xmas greetings program for sailors, Gruß an Bord (Greetings Aboard), on shortwave, December 24th.

Here are the frequencies from the official NDR press release [reception reports are encouraged]:

From 19.00 until 21.00 UTC (20.00 until 22.00 clock CET) on December 24, 2015:

FREQUENCY DESTINATION
6185 Atlantic – North
11650 Atlantic – South
9830 Atlantic / Indian Ocean (South Africa)
9885 Indian Ocean – West
9810 Indian Ocean – East

From 21.00 to 23.00 UTC (22.00 to 24.00 clock CET) on December 24, 2015:

FREQUENCY DESTINATION
6040 Atlantic – North
9655 Atlantic – South
9830 Atlantic / Indian Ocean (South Africa)
9515 Indian Ocean – West
9765 Indian Ocean – East

Reception reports are welcomed at [email protected].

Here are direct links just in case NRD changes a frequency:

http://www.ndr.de/info/sendungen/So-empfangen-Sie-die-Gruss-an-Bord-Sendungen,grussanbord326.html

http://www.ndr.de/info/sendungen/Gruss-an-Bord,grussanbord306.html

WTWW Christmas Shortwave Radio Picture Contest

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Yes, though I'm not entering the contest, I am getting into the spirit of the season!

Though I’m not entering the WTWW contest, I *am* getting into the spirit of things!

(Source: WTWW via David Korchin, K2WNW)

It’s Christmas music on International Shortwave Radio Station WTWW. We want the shortwave radio to take the place of the electric train under the Christmas Tree! We are asking for pictures of your shortwave radios – the most festive picture wins! Include yourself, friends and family, include the Christmas tree, or deck your radio with boughs of Holly and all things Christmas!

Send your pictures to [email protected] for the chance to win the Grand Prize – a TW 2010 Antenna complete with the quadra stand and custom carry bag! During the week we are starting on 5085 kHz at 7pm CST until 11pm CST. On the weekends we are starting at 1pm CST on 9930 kHz until 7pm when we change to 5085 kHz and it will go until late into the night.

Blow the dust off of those classic radios and get them out of the closet or attic and Tune In for Bing Crosby, Montovani, Dean Martin, Burl Ives, Mannheim Steamroller and many more. There is nothing like the sound of Christmas music coming out of the speaker of a classic shortwave radio.

We will even accept creative pictures of not so classic radios and newer radios including SDR’s that look festive and capture the spirit of Christmas. We also love and welcome videos with WTWW playing in the background. If you think your radio can make Santa smile, then send us your picture – you could be our big winner! Other prizes will be announced as we go along.

[email protected]

or

WTWW
P.O. Box 102
Lebanon, TN 37088

Phil’s initial impressions of the Degen DE27

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Degen-DE27

Many thanks to SWLing Post reader, Phil Ireland, who comments:

I’ve just received my Degen DE27 from China. Interesting little radio, I haven’t had a good chance to put it through its paces yet but my initial impressions are the radio seems well built and fairly intuitive to turn it on.

However, all the instructions are in Chinese so luckily there was someone in my office who could set the language to english otherwise, setting up the radio is a nightmare! I will have to take the radio outside to test its performance as the office environment is useless to listen in.

The box says the radio tunes from 3.2 mhz to 21.850 mhz however, I havent been able to work out how to make it tune out of the standard SW Broadcast Bands yet. Toggling between 10 khz and 9 khz steps for AM is easy as it setting the FM band coverage but I’m yet to determine the SW settings. It appears tuning is only in 5 khz as well on SW.

As for venturing into MP3 settings and recording, I’ll leave that, it seems too much of a challenge! The clock and calendar, sleep timer, alarms are all fairly straight forward but there is an “E-Book” setting which defies description! It has a USB flash disc function and inputs for a micro SD card. Charging the supplied Lithium battery is via a supplied USB cable.

The display is easy to read and attractive with excellent backlighting. I’m not expecting stellar performance on any band, after all, it was a cheap radio (about 40 AUD with free postage) but it is built around DSP architecture. Only a single bandwidth is available and there is no SSB capabilities. The radio hopefully will be ideal to throw onto a backpack or pocket as a travel portable.

If DEGEN read these comments, perhaps an English manual put online would be extremely helpful to allow users to get the most out of the DE27.

I’ll comment more on the performance later but for now, the radio shows promise.

Thanks so much for sharing your initial impressions, Phil! Please keep us informed as you discover more about this little radio!

This reminds me that I have yet to put my Degen DE221 through the paces. Stay tuned!