Category Archives: Articles

National Radio Quiet Zone featured in BBC Radio 4 series

Jeffrey re-caps his Hallicrafters SX-110

The restored SX-110 sitting on the bookshelf in the shack.

Many thanks to SWLing Post reader, Jeffrey Fritz, writes:

During the summer of 2012 you were nice enough to run an article in your blog about my reviving a 1961 Hallicrafters SX-110 General Coverage receiver. The radio has continued to perform reasonably well during the last few years. However, recently I acquired several pieces of professional test equipment. That encouraged me to delve even deeper into the restoration of my old receiver from my novice ham radio days.

Over the past week, I completely recapped the SX-110 (except, of course, for the mica and ceramic caps as they still good, and the electrolytic caps as they were replaced in 2012.)

The SX-110 isn’t a complex receiver, but there are quite a few caps, so I worked methodically and carefully. I started working from the audio amp stage and continued working back through the IF stages and the BFO to the RF stage. I recapped each stage replacing the old caps with new Orange Drop caps. Each stage was tested before I moved on to the next stage. Here’s a photo of the recapped chassis:

Here are the capacitors that were removed from the receiver. Most are the old Bumble Bee caps–called that because of the color stripes that mark their value:

Virtually every Bumble Bee cap tested leaky and out of tolerance.

Next, I tested every tube replacing the weak or bad ones with NOS (New Old Stock) tubes. Every pot and switch was cleaned with DeOxit and moving parts were lubricated where appropriate. Finally, I did a complete re-alignment following the instructions in the Service Manual.

As with all vintage tube gear, restorations require patience, care and a decent knowledge of electronics. It’s easy to make a fair radio–even a good radio–into a disaster if you are not careful. Also there is enough voltage and current inside of the chassis of a tube radio to toss you across the room. So care is always the order of the day as is a VARIAC to bring the radio up to AC line voltage slowly.

The receiver now sounds as good as ever–perhaps even better than ever. It has marvelous AM audio and can pick up ham and broadcast stations on all bands with nothing more than a wire in my basement. It even does a decent job on SSB–something that I don’t recall it ever bring adept at in the past.

That say that you can’t keep a good man down. Similarly an old radio, with some new parts and some TLC, can run virtually forever.

I agree with you: you can’t keep a good radio down! Repair work is certainly the commitment we make when we fall in love with these old rigs. It’s a good thing that almost all of the parts are still available and relatively affordable.

Thanks again, Jeffrey!

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Wojtek Gwiazda retires from RCI

Sean’s A15 Season International Broadcasting Statistics

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Many thanks to Sean Gilbert, International Editor at the World Radio TV Handbook, who is kindly sharing some international broadcasting statistics with us again. These statistics were originally posted on the WRTH Facebook group:

Seasonal Language Output Comparison

[F]or the top 19 languages used in international (and Domestic SW) broadcasting. There are 10 seasons worth of data to compare. In those 10 seasons, we have seen an overall drop of 33%, the biggest casualties being Farsi, German, Portuguese, Spanish, Russian, English & Indonesian. Tibetan is usually fairly stable with it’s output being pretty constant over the past 9 seasons – this season, however sees a huge increase in output (+69%), mainly due to the USA hiking output of the language this season. In sheer numbers of data lines (which is how this table has always been generated), English is the biggest casualty, dropping 104 transmission periods per week.

Click to enlarge.

A transmission period is based on the following data structure:
Shown below are 2 “transmission periods” for WWCR and 1 for WWRB. 2 in English and 1 in Spanish. These transmission periods cover a weeks worth of output on that frequency at that time for that broadcaster.

WWCR 1630-2100 English wcr 100 NAm,Eu,NAf daily 15825
WWCR 2100-2200 Spanish wcr 100 NAm,Eu,NAf daily 15825
WWRB 0100-0400 English wrb 100 NAm daily 3195

So a transmission period could, in reality, be from 5 minutes on a single day to 24 hours, daily, depending on the broadcaster. There are nearly 5000 of these entries in our database for this season (When I started at WRTH back in 2000, there were over 10000 entries). Of these 5000 entries, over 3600 are taken up by just 19 languages. The other 1400 entries share somewhere in the region of 200 languages/dialects and combinations! Although this doesn’t show how many hours a particular language has decreased by, it does show the ongoing trend in International broadcasting by radio.

A15 International Broadcasting Season Facts

There are 191 schedules listed in the International Radio and COTB (Clandestine & Other Targeted Broadcasts) section of the WRTH A15 schedules file.

Who uses the most frequencies? CRI, with a whopping 279 frequencies in use. The next largest station, by frequency use is (probably quite surprising to many of you) Voice of the Iranian Republic of Iran (VOIRI) with 140 (that is half the amount of CRI!). Next is VOA with 126; then RFA at 112; BBC at 110 then Sound of Hope Radio International with 84 and All India Radio at 67.

Below is a list of the ‘Top 20’ broadcasters in terms of frequency usage. If you were to do a study of actual transmitted time, the list would look rather different. I will shortly post a table showing the top languages, by use, and what has changed over the past 10 broadcasting seasons.

CHINA RADIO INTERNATIONAL (CRI): 279 frequencies
VOICE OF THE ISLAMIC REPUBLIC OF IRAN (VOIRI): 140 frequencies
BBG – VOICE OF AMERICA (VOA): 126 frequencies
BBG – RADIO FREE ASIA (RFA): 112 frequencies
BBC WORLD SERVICE: 110 frequencies
SOUND OF HOPE RADIO INTERNATIONAL: 84 frequencies
ALL INDIA RADIO (AIR): 67 frequencies
RADIO ROMANIA INTERNATIONAL (RRI): 56 frequencies
AWR ASIA/PACIFIC: 52 frequencies
RADIO JAPAN (NHK WORLD): 49 frequencies
VOICE OF TURKEY (VOT): 43 frequencies
RADIO TAIWAN INTERNATIONAL (RTI): 41 frequencies
BBG – RADIO FREE EUROPE/RADIO LIBERTY (RFE/RL): 33 frequencies
KBS WORLD RADIO: 32 frequencies
SAUDI INTERNATIONAL RADIO: 32 frequencies
AWR AFRICA/EUROPE: 30 frequencies
VATICAN RADIO: 29 frequencies
RADIO CAIRO 29: frequencies
VOICE OF KOREA (VOK): 27 frequencies
FEBC PHILIPPINES: 26 frequencies

63 broadcasters, or so, use just a single frequency.

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Improving audio fidelity with JBL C2PS monitor speakers

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Last year at the W4DXCC conference in Sevierville, Tennessee, I spent some quality time with Bob Heil (K9EID). Bob is the mastermind behind Heil Sound as well as the host of HamNation, a show devoted to all aspects of amateur radio––yet this job description only scratches the surface of Bob’s fascinating career.

Bob Heil (K9EID, left) and yours truly (right) at the 2014 W4DXX conference in Sevierville, TN

One thing is for sure, however: there are few people in the radio industry who truly understand audio as profoundly as Bob Heil, so when he announced that he would host a forum at the W4DXCC to assist amateur radio operators in improving their received (and transmitted) audio, we were all ears, and signed right up.

Early in the forum, Bob described a set of self-powered and relatively affordable JBL monitor speakers that he highly recommended for amateur radio use. Everyone in the room noted the model number of the speakers, myself included. So imagine my dismay after the convention when I simply couldn’t find my notes…

Thankfully, my buddy Gary Wise (W8EEY) recently jogged my memory. Gary purchased a set of JBL monitors and matching wall-mount brackets from Amazon, and has them hooked up to his Flex Radio FLEX-6700 SDR. Gary tells me he’s very pleased with the set-up. Here are the links:

Bob also suggests adding a small mixer to system, something like this Behringer Xenyx 802 or the XENYX502 (both of which are on my current wishlist).

Bob invited me to speak on HamNation about shortwave radio. I may take him up on the offer…well, as soon as I overcome my videophobia, that is. At any rate, if you’ve not seen it, HamNation is certainly worth checking out. And in all things radio, Bob Heil’s is a name to know; click here to visit Heil Sound.

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ARS Technica: People turn to ham radio in aftermath of Nepal earthquake

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Many thanks to SWLing Post reader, John Drake, who shares this excellent article from ARS Technica:

“On Saturday, Nepal was shaken by a massive earthquake that registered a 7.8 on the Richter scale, causing widespread destruction in areas of dense population, and preventing aid workers from reaching more isolated villages in the mountainous regions. As of Tuesday, at least 5,000 people were dead and at least 10,000 were injured. Hundreds of thousands of people have been left homeless.

With any natural disaster, communication can often become a matter of life and death, and if phone lines are broken and cell towers crumble, relaying messages to the outside world and coordinating rescue efforts becomes that much more difficult. Add to that the fact that Nepal’s government is woefully unprepared to handle such a humanitarian crisis, and chaos reigns.

Still, some volunteers are trying to impose order on the chaos. After the quake, which shook cities in India as well as Nepal, volunteer ham radio operators from India traveled to the region to relay messages from areas whose communications infrastructure is broken or overloaded. Ham radio, also called amateur radio, is a means of sending and receiving messages over a specific radio frequency, and it is often used in disaster situations because it operates well off the grid; transceivers can be powered by generators and set up just about anywhere.

Amateur radio has taken a back seat with hobbyists in recent decades as other means of wireless communication have become cheaper and easier for people to use (you don’t need a special license from the FCC to operate a cell phone, although sometimes it seems like we’d be better for it if that were the rule). The decline in participation rates is unlikely to change substantially in the US, and the Times of India noted that awareness about ham radio is still low in India and nearby areas. Still, it has proven to be effective as a means of communication in Nepal in recent days.”

Continue reading on ARS Technica…

Transceivers like the Elecraft KX3 (above) are perfect for aid workers in need of communications in the aftermath of a natural disaster. Many modern transceivers (like the Kx3) can run for hours at a time off of battery packs, can be deployed almost anywhere and can easily be attached to amplifiers if needed.

It may take a license to operate amateur radio, but frankly it’s a fairly low barrier of entry. Morse Code tests are no longer required here in the US and all of the questions and answers are multiple choice and in the public domain. Indeed, I found the Technician (and former Novice) license test to be incredibly educational; especially with regard to radio propagation and basic electronic principles.

Everyone should support their amateur radio clubs who actively hone their emergency communication skills. As the ARRL often quotes: “When all else fails…amateur radio.” Even if you don’t have a license, amateur radio clubs welcome visitors. You can find a fairly comprehensive list of amateur radio clubs (in the US) via the ARRL.

Click here for a list of amateur radio organizations worldwide.

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