Category Archives: Radios

SWLing with heavy metal: my Signal Corps BC-348-Q

SignalCorps-BC-348-Q

I write a great deal about DSP portables, SDRs, and modern ham radio transceivers, but truth be known, my passion is for older rigs–ahem, much older–the antique “boat anchors” of the radio world.

Tuesday afternoon, I had a rather involved soldering project to do on behalf of my organization, Ears To Our World.  While I worked, I decided to fire up my Signal Corps BC-348-Q to hear what was on the air. I promptly discovered Radio Exterior de España on 17,850 kHz–starting with their interval signal; REE, care of my BC-348-Q, kept me company while I soldered almost three hundred connections.

The BC-348-Q frequency dial

The BC-348-Q frequency dial (Click to enlarge)

I listen to my BC-348-Q nearly every week. Usually, she’s tuned to 9,580 kHz for my morning dose of Radio Australia.  In the winter, the ‘348’s tubes keep my little radio room a little warmer than the rest of my house. In the summer–well, I just sweat a little more.

I love this radio, and my other “boat anchors,” because when I listen to these rigs I can’t help but hear the past.  I wonder about the others who have listened to the same radio, and what was happening in their lives as they listened…

The BC-348 series, for example, is well-known for its use in WWII allied bombers–these rigs were mounted in the likes of the B-17, B-24, B25, and others of the era. Indeed, mine still has the original clips on the base that anchored it to the radio operator’s onboard work table. The ‘348 was used as a long-distance liaison receiver during WWII. 

The B-17 radio operator's position (Source: AZ Commemorative Air Force)

The B-17 radio operator’s position (Source: AZ Commemorative Air Force Base)

The BC-348 series was built with simplicity, functionality, and serviceability in mind. It was built to withstand life on a B-17 bomber–the extreme vibration on start up, the extremely low temps in the upper atmosphere; it could be serviced by the radio operator in flight, if necessary. Its controls are simple, bare-bones, even. The tuning knob and analog dial are beautifully engineered and precise.

The ‘348 has a power switch, volume control (switchable from auto to manual gain), crystal filter, CW switch, beat frequency control, tuning knob, and a band switch (located just below the dial). The antenna and ground terminals are mounted on the front of the radio for easy accessibility. All controls are spaced so that the radio operator could use the ‘348 even while wearing thick cold-weather gloves.

BC-348-Q-FrontControls

You can’t do any medium wave DXing on the ‘348, however: this receiver was intentionally designed with the medium wave band omitted. Evidently, Uncle Sam wanted radio ops to be focused on communications instead of entertainment (but that’s okay; the government also made morale radios for the latter).

When I go to the Dayton Hamvention–or any hamfest, for that matter–it’s radios like the BC-348-Q I seek. Tube/valve radios sometimes lack the sensitivity and (digital) accuracy of modern tabletop shortwave receivers, but they make up for this in audio fidelity. As long as you have a properly-matched speaker, the sound can be…nothing short of amazing. Even though the ‘348 was never designed for robust audio, it still sounds richer and fuller than most modern tabletop radios. The sound is so warm it literally glows. Moreover, I’d be willing to wager that there are few modern receivers that can stand the test of time like these rigs.

BC-348-Q-Label

If you buy one of these old beauties, you must be ready to service them; inevitably, a capacitor or tube will fail in time.  But they just…keep…going.

I’m very much in debt to my good friend and radio elmer, Charlie (W4MEC) who kindly teaches me everything I need to know about these great rigs. He’s exceedingly patient, and that counts for much, as I’m not by nature technically inclined. But I do enjoy learning about these radios and how to service them; the romance of their history draws me in, and I simply can’t get enough.

Note: It’s important to work with a knowledgeable elmer/mentor or a professional repair technician when servicing these boat anchors, because, unlike with our modern radios, their high voltages can severely injure (or even kill) you if you don’t know exactly what you’re doing inside the chassis.  This is repair work for the professional.

BC-348-Q-FrontView

My BC-348-Q turns 71 this year–and I’m sure it has at least that many more years to go. I know that I’ll give it as much TLC as it can take. We must keep these still functioning pieces of history on the air.

If you, too, have boat anchors or antique radios alongside your modern rigs, please comment! I’d love to learn about your favorites. In other words, what heavy metal is in your shack?

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Where to buy shortwave radios in New Zealand?

ElisabethAndPerI received a message this morning from a Norwegian couple, Per and Elisabeth, who are circumnavigating the globe in a sailboat.

They’re currently in Opua, New Zealand, and are looking for a shortwave receiver with SSB mode.

They depart New Zealand on May 6, 2014 so are very much in a hurry to find one.  They plan to use this radio to receive weather fax while on the open sea. Personally, I would hope they could find a good tabletop receiver for the job, but they would be happy with a capable portable radio.

On a side note, I’m well aware that the Digitech Audio AR1945 is readily available in New Zealand, but based on comments from a previous article, I also know that it performs miserably on SSB.

If you can help Per and Elisabeth find a shortwave radio with SSB in New Zealand, before they depart on May 6, please comment!

You can follow Per and Elisabeth’s sailing adventure on their website and blog.

Hidden feature: Calibrating the Tecsun PL-880 for zero-beat operation

Tecsun-SSB-QRG-1Many thanks to Dan who learned, via the Tecsun PL-880 group, of another way to calibrate the PL-880 in upper and lower sideband. This method seems to be a little easier than a previously posted procedure.

Anna, with Anon-Co, translates this procedure given to her by Tecsun technicians:

  1. Place the Tecsun PL-880 in LSB or USB mode
  2. Tune to an AM broadcast station and zero-beat the signal (fine tune it until the signal has no SSB distortion and voices/music sound natural)
  3. If the last two digits of the frequency are not “00”, this means there is some display deviation
  4. Simply press and hold the [SNOOZE] button for about one second or so to calibrate the last two frequency digits, which will show “00” when successful.

I will try this procedure later today by re-calibrating my PL-880.

Dan has also noted what many others have–that the PL-880 “is sensitive to both power levels, and time in the powered on state, and will vary by some hz up and down the bands
no matter what one does to zero at any particular point.”

Has anyone else experienced this?

Yaesu FT-817 as a travel receiver

SWLing Post reader, Anil, comments on Traveling light, SWLing right:

Yaesu-FT-817

The Yaesu FT-817nd general coverage QRP transceiver

“I would like to suggest another candidate that is really hard to beat and is fantastic value when you buy a used one – The Yaesu FT-817 Low Power Transceiver.

It has outrageously good General Coverage performance and a massive LF – UHF coverage receiver. It has the same paperback footprint as many of the travel radios you review and a built in battery pack albeit a fairly low capacity one.

When it comes to extracting weak signals out of noise and interference it is head and shoulders above the rest with a switchable pre-amp, variable RF gain and attenuator, pass-band tuning, narrow filters etc.”

Anil, you’re right. The FT-817 is a very compact, full-featured radio and certainly easy to pack.

Yaesu-FT-817ND

I was an early adopter of the ‘817, having purchased mine in 2000 or 2001. I was living in the UK at the time and traveled extensively throughout Europe for my employer. I looked to the FT-817 as a means to play ham radio on the go. It easily fit into my carry-on bag at the time.

Like you, I was very pleased with the receiver though I had nothing to compare it to at the time.

I kept the FT-817 for about five years, but eventually sold it. I started using the Elecraft KX1 as its replacement.  I found that, for me, the ‘817’s front face was a little too small and some of the multi-function knobs could be a little frustrating to use while on the air. Those were relatively minor criticisms, though–the ‘817 continues to have a large fan base and is enjoying very long product life.

Anil, many thanks for sharing your comment!

Click here to check out the Yaesu FT-817 at Universal Radio or click here to search eBay for a used one.

Monitoring while recording on the Tecsun PL-660

BlueTooth

London Shortwave has discovered an innovative way to monitor broadcasts while recording from his Tecsun PL-660. He writes:

“Tecsun PL-660 doesn’t have a line out, which means that when recording from it one has to use a pair of headphones to listen to it simultaneously.

Most portable speakers I’ve tried generate tremendous amounts of RFI when connected directly to the receiver. I solved this problem by using TaoTronics BA-01 Bluetooth audio transmitter and a Bluetooth enabled portable speaker, together with a cable that splits the audio output into two, so the transmitter and the audio recorder can both be connected to the radio.

The recording [in this YouTube video] is of Radio Australia and was made in London, UK on 09/04/2014 at 1543 BST.”

Chris field records NHK while traveling in Peru

Chris-Peru

SWLing Post reader, Chris, has just shared a recording of NHK World he made while traveling in Peru on Monday (April 21st, 2014).

Yes, that’s his photo above taken in the picturesque coastal town of Máncora. Can you tell I’m envious? 

Chris recorded this broadcast starting at 10:00 UTC on 9,625 kHz with a Sony ICF-SW7600G and using a Sangean ANT-60 antenna. The actual recording was made with Chris’ Sony ICD SX712 digital recorder and he uploaded it using a Dell Windows 8.1 (8 inch) tablet.

That, Chris, is a nice field recording combo!

Click here to download his recording as an MP3, or simply listen via the embedded player below. This recording will also be available on the Shortwave Radio Audio Archive.

Results of the Shortwave Portable weak signal shoot-out

RadiosShootOut-SonyTecsunSangean

Thanks to all who participated in our shoot-out!  Last week, I posted three recordings of a weak shortwave broadcast in an attempt to evaluate which recording–thus which radio–our listeners prefer. The test was “blind” in that, though four radios were evaluated, only three recordings were posted, merely labeled, “Sample #1,” “Sample #2,” and “Sample #3,” respectively.

The radios tested were not just average radios. Rather, they represent the best of the truly portable radios currently on the market, namely: the Sangean ATS-909X, the Tecsun PL-880, the Tecsun-PL660 and the Sony ICF-SW7600GR.

Indeed, the most popular question I receive from SWLing Post readers is about two or more of these models, asking,”which is best?”

The samples

To refresh your memory, I’ve embedded the audio samples below–but if you haven’t yet, I would encourage you to read our previous post (and the great reader comments following!) before proceeding.

The recordings in our samples are of Radio Romania International on 11,975 kHz. Normally, the signal would have been stronger, but propagation was rough, and QSB (fading) was pronounced at times. Note that I recorded all of these samples with my Zoom H2N digital recorder via a line-in connection, using the radio’s headphone jack. Since not all of the radios have a line-out jack, I used the headphone jack each time and simply set the volume and line-in gain to the same level.

Sample 1:

Sample 2:

Sample 3:

And now, here is the sample I intentionally left out in my previous post…Sample #4. I didn’t include it in the evaluation because, frankly, it was such a weak performer compared with the other three; I knew it would take last place:

Sample 4:

With that in mind, we’ll start with the radio behind Sample 4:

Sangean-ATS-909X

Sangean ATS-909X ($200-250 US)


Many readers guessed rightly that the Sangean ATS-909X was the radio omitted. Evidently, it is known for its lack of sensitivity when only employing its telescoping whip antenna. You’ll notice that, most of the time, the RRI broadcast is lost in the static.

Frankly, I was somewhat surprised that the ATS-909X didn’t perform better. It has a loyal following amongst SWLing Post readers and has been a popular radio on the market for the past three years or so. While I’ve used the ATS-909X in the past, I have never owned one, and had never done a side-by-side comparison.

To perform this test, I borrowed the 909X from a friend who usually has it hooked up to an external antenna. In fact, this is when I learned that the 909X performs admirably when hooked up to an external antenna.

In my tests, however, I didn’t want to hook up external antennas.  I believe that for a radio to be evaluated as a portable, it must be judged on its ability to receive signals from its telescopic whip antenna as a base line.

But let’s move on to the radios you did hear in our weak signal evaluation…

Let’s take a look at the radio behind Sample #3, the radio our readers voted to take last place in terms of weak-signal listening:

Tecsun-PL-880

Tecsun PL-880: Sample 3 ($150-160 US)


With the exception of three votes (out of more than seventy), Sample #3–the Tecsun PL-880–was overwhelmingly voted worst in this weak-signal shoot-out.

The bulk of your criticisms focused on the fact that the PL-880 did not handle fading as well as the other radios. When the signal was at a peak, it sounded great, but in QSB troughs, the signal became unintelligible and you could hear DSP artifacts and distortion.

But is the PL-880 a “bad” radio? Absolutely not. Indeed, I gave it pretty high marks when I reviewed it last year. It’s just not the best choice for weak-signal listening–at least in its current firmware version.  Note to Tecsun:  I do believe it may be possible to tweak this portable’s AGC circuit so that it handles fading better…

But let’s move on to the other contestants. Here’s our second-place portable:

Tecsun-PL660

Tecsun PL-660: Sample 2 ($110-130 US)


During the first day of voting, the Tecsun PL-660 actually had a noticeable lead on the other radios. I’m not surprised. The sensitivity was better than the rest of the contestants, in my opinion. The received audio was clear and seemed to pop out of the static better than the others.

Overwhelmingly, those who didn’t vote the PL-660 as best, voted it as second. Their main criticism was that the PL-660’s AGC was a little too active and less stable than the radio which actually took first place.

And with no further ado, here’s our winner:

Son-ICF-SW7600GR

Sony ICF-SW7600GR: Sample 1 ($130-150 US)


Surprised?  I was!

After I evaluated the blind test myself, I was certain the PL-660 would be the winner with its stronger sensitivity. But the result–and reader comments–proved me wrong. More of you placed a value on the Sony’s rock-solid AGC circuit which handles the peaks and troughs of fading better than the other contenders.

Commenters noted that the Sony’s audio and stability lent itself to easier, less fatiguing, listening. Keep in mind, though, that many of these same commenters mentioned that the PL-660 (Sample #2) would be their preference for identifying a station in under weak signal conditions.

Now let’s look at the raw data, and then discuss what it all means.

The data

The Sony ICF-SW7600GR was voted:

  • first place 41 times,
  • second place 2o times, and
  • third place once

The Tecsun PL-660 was voted:

  • first place 23 times,
  • second place 33 times, and
  • third place twice

The Tecsun PL-880 was voted:

  • first place never,
  • second place three times, and
  • third place 53 times

I’ve attempted to place this data into a bar graph to make it a little easier to visualize: RadioShootOut-ResultsIf you noticed that these numbers don’t completely add up, it’s because responses were inconsistent.

Most survey participants listed their preferences in order (i.e., first, second, and third place). Some respondents only listed their favorite of the three, while others only listed the one they didn’t like. No one responded with a tie between the radios, all had an opinion.

Another way of reading the results

SWLing Post reader “Radio Flynn” helped me with some additional data interpretation this morning. He put together this analysis (download as a PDF), and commented:

“[A]lthough a majority of people choose sample #1, nearly everyone ranked either sample #1 or sample #2 as preferred, and the average ranks are very close, closer than the raw percentages would indicate. I have not done a statistical analysis so I don’t know if the difference in mean rank between #1 and #2 is significant (in other words, I don’t know if there is a significant preference for #1), but you can say that either sample 1 or sample 2 would be acceptable to almost everyone, and sample 3 clearly last choice.”

Radio Flynn also pointed out that next time I do this sort of test (and I will be doing another!) that I should keep votes consistent by asking everyone to rank their preference. Excellent suggestion; I’ll be sure to do so.

So the Sony ICF-SW7600GR is the best radio…right?

Not exactly.

Herein lies the difficulty of suggesting the “best” radio for any particular listener.

This test only evaluated weak signal sensitivity under rather rough conditions. The Sony was “the winner” in this respect.

SideBySide-FourRadiosBut this doesn’t tell the whole story.

I’ve had my Sony ‘7600GR longer than any of the other portables in this contest and it is invariably the radio I reach for when I want to make a field recording. I prefer the Sony because it has good sensitivity, a stable AGC, excellent single-sideband selectable sync detection and it can handle being connected to a long external antenna. Indeed, it was the Sony I packed when I spent the summer of 2012 in an off-grid cabin in the Canadian maritimes. In short: my Sony ICF-SW7600GR is my “old faithful.”

But frankly, when I travel, I reach for the PL-660 more often than not. Why?  Yes, the Sony has great receiver characteristics, but its ergonomics leave a lot to be desired. I use my Sony when I plan to key in a frequency and leave it there. The PL-660 is a joy to operate, has simple direct-frequency entry, an excellent auto-tune feature, not to mention, a stable sync detector.

If I want to identify a signal buried in the static, I reach for the PL-660.

If I want to do casual listening and am less concerned with DXing, I reach for the PL-880. It’s a solid radio and has a quality feel to it (running neck-and-neck with the ATS-909X in this respect). Of this bunch, it has by far, the best audio from its internal speaker. If I want armchair listening, I reach for the PL-880. It’s also an excellent SSB receiver–one of the best in this group–and offers more filter selections.

In summary, it’s not always easy to suggest which radio is best…I must ask in response, “Best for what?” The data from this test proves this, as our readers who ranked their favorites backed up their choices with consistent and valid comments.

What do you think?

Before long, I plan to pit these radios (and perhaps another?) against each other in terms of their synchronous detectors in another blind test.  It may take a while to work this up. Your enthusiastic responses, however, completely justify it.

Stay tuned!

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