Category Archives: Accessories

Tom’s Recommendations: Earbuds and EQ Settings for Shortwave Listening

Many thanks to SWLing Post contributor, TomL, who shares the following guest post:


Earbuds for Shortwave Listening

by TomL

A few years ago I had bought the discontinued Sennheiser MM 50 earbuds for a cheap price on Amazon to use in my various radios.  The portable radios in particular can use more fidelity because of their small, raspy speakers.  I also like to listen without bothering others around me who might not want to listen.  And earbuds are a LOT more comfortable for my ear lobes than any over-the-ear headphones I have ever used.  Furthermore, the old Apple iPhone 4 earbuds were very harsh to listen to.  However, a trade-off is that, generally, earbuds are somewhat fragile; one of the two pairs of MM50’s died through mishandling.

I was generally happy with them while listening to Shortwave broadcasters with a mix of news/talk and music.  I especially liked them on Mediumwave listening; stations can sound surprisingly good when playing music.  Then I tried using these earbuds on my Amateur Radio transceiver, a Kenwood TS-590S.  I was impressed how clear they sounded with a lack of distortion, although there was too much bass.  Fortunately, Kenwood supplies USB connected software with an TX & RX 18 band EQ (300 Hz spacing, not octaves).

Here is a frequency response chart I found from Reviewed.com for this model:

One of the notable things about these earbuds is the total lack of distortion.  Most likely one of the reasons they sound so clear on Shortwave, which has many LOUD audio spikes.

I had not wanted to get Bluetooth earbuds.  However, I had recently upgraded my cell phone and NO headphone jacks anymore!  So, while I do not use Bluetooth yet for radios, I can see a time in the future to get a Bluetooth transmitter to plug into a radio with a headphone jack.  I am reluctant since I do not like having to recharge my earbuds and I put in a lot of radio listening time.  Am I supposed to buy two Bluetooth earbuds and swap while charging?  Maybe in the future.  And also, am I supposed to buy a Bluetooth transmitter for every non-Bluetooth radio I own?  Not likely gonna happen.

In the meantime, I ordered cheap wired earbuds from Amazon.  I had a $5 credit for trying Prime, so when I saw these Panasonic ErgoFit wired earbuds (RP-HJE120-K) for slightly over $10, I said to myself, “why not?”.   Supposedly wildly popular, they are one of the most rated products on all of Amazon with 133,821 ratings/opinions (perhaps Russian bots?!?!?).

Here is a frequency response chart from ThePhonograph.com for these Panasonic earbuds:

You can see comparatively that the bass response in the very good Sennheiser MM50’s is much stronger, being good music earbuds.  But for voice articulation, not as much, even though they have no distortion.  The Panasonic ErgoFit’s have more modest bass, less of a dip in the lower midrange audio frequencies, and more importantly, has a peak near 2500 Hz and its harmonic 5000 Hz.  The highest highs are also modest compared to the Sennheiser model.  This general frequency response to “recess” the bass and treble frequencies and peak the 2500 Hz is very useful for voice intelligibility.

As described by the famous speaker-microphone-sound-system maker, Bob Heil relates what he learned from the scientists at Bell Labs many years ago.  Speech intelligibility is enhanced when audio is compensated for our natural human hearing.  Equalizing below 160 Hz, reducing the 600-900 Hz region, and peaking the 2000-3000 region centered at 2500 Hz will increase intelligibility dramatically.  The story goes that Bell Labs was tasked by parent AT&T with finding out why the earliest phones in the 1920’s sounded so muffled and hard to understand.  After many experiments, the scientists found the most important frequencies for our ears + brain to comprehend speech.  In other words, our ears are not “EQ-flat” like a scientific instrument is. Continue reading

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One last call for SDRplay RSP1A metal cases!

Many thanks to SWLing Post contributor Dave (N9EWO) who writes:

Thomas, FYI

RTL-SDR.com decided to make one LAST production run of the RSP1A metal cases. These are now available on Amazon for $34.95 until stocks run out.

73
Dave Zantow N9EWO.

Click here to view on Amazon (affiliate link).

Thank you so much for the tip, Dave!

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The C.Crane Digital FM Transmitter 3

Many thanks to SWLing Post contributor, Ron, who shares information about the latest C.Crane FM transmitter:

Check out the new C.Crane FM Transmitter 3.

Everything is the same as the previous model except it now covers 87.7 to 108 MHz.

People have been reported as being in big trouble for using 87.7 MHz, or is it because of their competitor, the Whole House FM Transmitter? This also covers the entire band but has serious build quality defects according to the Amazon reviews and costs more than the C.Crane FM-3.

Click here to check out the C.Crane FM Transmitter 3.

Thanks for the tip, Ron! Like many, I use FM and AM transmitters to pipe Internet radio streams throughout my house: especially the UK 1940s Radio Station!

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The Nextube retro nixie clock

Many thanks to SWLing Post contributor, Al Hearn (WA4GKQ), who writes:

Thomas:

I’ve just received this Rotrics NexTube [see photo above] after a year of waiting. It was a KickStarter project and suffered numerous delays, and is just now shipping. It’s beautiful — real walnut wood, glass tubes and brass fixtures.

It appears at first glance to be yet another imitation Nixie tube clock but it’s actually much more than that. Each tube is a high-res IPS display that can display almost anything, including photos. It’s highly configurable, uses WiFi to connect to the Internet, and has an (yet undocumented) open API.

Being a ham and SWLer, I can envision someone much smarter than I programming this device to show real-time propagation data from beacons, propagation forecasts, etc. or other information of interest to those of us in the hobby. Imagine each of the six tubes graphically showing real-time band conditions on six different ham bands. It can already be used as a GMT clock. A set of three touch buttons allows app switching and user interaction.

With your infinite access to members of our hobby, I thought maybe you could find a way to expose this to those who might have an interest and expertise to create such an application for this amazing little device. I believe that its potential is almost unlimited, in ways the creators haven’t imagined.

73,
Al Hearn
WA4GKQ

Thank you for sharing this, Al! What a beautiful, modern take on the Nixie Tube clock! I love the simple design and versatility.

I’m very curious if any other readers have purchased the Nextube or have tinkered with the API. Please comment!

Click here to check out the Nextube at Rotrics.

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A happy accident, and some experiments

By Jock Elliott, KB2GOM

When you live in an antenna-challenged situation as I do (stringing long wire antennas outside is problematic for me), the result is a never-ending search for an improved signal.

Toward that end, I’ve experimented with a horizontal room loop, an indoor end-fed, and a short dipole.

Along the way, I decided to test the MFJ 1020C active antenna/preselector, and I liked it pretty well. My conclusion was: Bearing in mind that it won’t improve every signal you want to hear, if you live in an antenna-challenged situation, the MFJ 1020C – particularly if you can get 20-50 feet of wire outdoors or run around the perimeter of a room – may be just what the doctor ordered.

After my test of the 1020C, I had an online conversation with Andrew (grayhat), and he suggested that I might want to have a look at the MFJ 956 passive selector.  Its major claim to fame is: “Boost your favorite stations while rejecting images, intermod, and phantom signals!  The MFJ-956 Pre-Selector/Antenna Tuner greatly improves reception from .15 to 30 MHz — especially below 2MHz.  It has tuner bypass/ground receiver positions.  The MFJ-956 measures a compact 2 x 3 x 4 inches.

MFJ was kind enough to send a 956 to me, and while I did not test it below 2 MHz, I found that it proved very helpful in tuning in the BBC mid-winter broadcast to Antarctica. I started out with the MFJ 1020C. Lots of noise and fades. Reception was somewhat better using the 1020C (compared to bypass), but then I switched to MFJ 956. I found I could copy better with the 956, even though it provides no amplification. Tuning slightly off-peak offered the best copy, better than bypass. I was listening in USB. In all, it is a useful piece of gear.

While poking around the MFJ website I discovered the MFJ 1046 Receiver Preselector, 1.6-33 MHz. Among other claims, MFJ has this to say about the 1046: MFJs new Passive Preselector has extremely high dynamic range! It improves the performance of nearly any HF or shortwave receiver/transceiver. It vastly improves the most expensive receivers. Especially helpful to those with broadband front-ends that are prone to overload.

Sounds promising, I thought, so I emailed Thomas, SWLing’s Maximum Leader, to see if maybe MFJ would like me to have a look at one.

A happy accident

A few days later, package arrived.

I was unpacking it when the Brain Dudes interrupted.

Brain Dudes:  Hey!!

Me: What?!!

Brain Dudes: That thing look a little weird to you?

Me: Whaddya mean?

Brain Dudes: Look at the front . . . what do you see?

Me: Well, on left, a knob labeled GAIN; next to that, and ON/OFF button; moving to the right, a BAND selector switch, and finally a TUNE knob.

Brain Dudes: And what is the MFJ 1046 supposed to have?

Me: A big tuning knob, an ON/OFF switch, and a BAND selector switch . . . maybe this is an improved model . . .

Brain Dudes: How ‘bout you look on the back panel . . . what do you see?

Me: The usual connections for antenna and receiver . . . and a plug-in socket for an external power supply.

Brain Dudes:  Is a passive preselector supposed to have a power socket?

Me: No . . .

Brain Dudes: OK, final clue, Sherlock: suppose you read the label on the front panel.

Me: MFJ 1045C. Holy smokes! They sent me the wrong unit!

(I hear the Brain Dude yelling at someone in the background: “Finally, the light comes on! I told you switching to decaf was a bad idea!)

Brain dudes: So they sent you the wrong unit; suppose you test it anyway since it’s here.

So I did. And it turns out that MFJ sending the 1045C instead of the 1046 was a happy accident because the 1045C, which is an active preselector, delivers excellent performance across the board.

This is what MFJ says about the 1045C: “Lets you copy weak signals. Rejects out-of-band signals, images. 1.8 to 54 MHz. Up to 20 dB gain. Gain control. Dual gate MOSFET, bipolar transistors for low noise, high gain. Connect 2 antennas, 2 receivers. Coax and phone jacks. 9-18 VDC or MFJ-1312D.

Once the antenna, receiver, and power supply are connected (I used the power supply that MFJ sent me with the 1020C), I operate the 1045C in much the same way as the 1020C:

  1. With the unit in BYPASS mode (the ON/OFF button out), tune the receiver to the frequency you want to hear.
  2. Set the GAIN knob to around 3 or 4.
  3. Set the BAND knob to the band with the MHz that you are tuned to.
  4. Press the ON/OFF/BYPASS button in. This turns on the active preselector and amplification circuits and a red light comes on to let you know the unit is activated.
  5. Slowly turn the TUNE knob back & forth. At some point in its tuning range, you will hear the signal and/or noise peak.
  6. Finally, adjust the GAIN knob for maximum intelligibility of the signal. Sometimes tuning slightly to the side of the peak works best.

I tested the MFJ 1045C with my end-fed indoor antenna (see link above) and with the short dipole (also, see link above). I also did head-to-head comparisons with the MFJ 1020C and those two antennas.

The results

Here’s what I found:

  1. The indoor end-fed antenna (which is 45 long) out-performs the short dipole (which is 6 feet total length) in all cases. That’s no surprise, but bear in mind that not everyone has a situation in which they can deploy the longer antenna. The 6-foot dipole definitely out-performs the whip antenna on my Satellit 800.
  2. The 1045C has a broader range of amplification than the 1020C. It appears to reject adjacent channel interference as well or better than the 1020C, and, to my ear, the 1045C has a lower noise floor. If you turn the GAIN knob fully to the left, it gets to a position where it appears to actually attenuate the signal. And I never found a situation in which, if properly tuned, the signal delivered by the 1045C was at least equal to the bypass signal, and many times it was significantly better. In short, in the HF range the 1045C appears do to everything that the 1020C does (with the exception of the 1020C’s screw-in whip antenna) and do it better.
  3. When using the 1045C with a portable (my Tecsun 880), I found that I could hear the noise peaks better than with the 1020C, which is a great help in tuning for best performance.

So why would you chose the 1020C or the 956 over the 1045C? Short answer: if you are a MW or LW enthusiast. According to MFJ, the 1045C covers 1.8 to 54 MHz; the 1020C covers .3 to 40 MHz, and the 956 covers 150 kHz to 35 MHz.

However, if you are an HF weenie like I am who enjoys teasing out faint signals, and particularly if you are faced with a sub-optimal antenna situation, the MFJ 1045C, in my opinion, is definitely worth a try.

Click here to check out the MFJ-1045C.

Shameless plug: check out the SWLing Post Message Board there are often interesting discussions going on there.

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Armed Forces Day QSL Card

On May 14, 2022, this blog published an announcement of the Annual Armed Forces Day Crossband Test.

The blog included a link to a PDF file that listed all the details, such as times, frequencies, and military stations that were participating (including some that were aboard ships), and there was even a link where you could submit your information online to receive a QSL card. I thought it would be fun to see if I could hear some of the military stations.

At 3:29 pm on May 14, I posted a comment on the blog:

1850Z & 1925Z — 14.487 MHz — Station sending CW CQ CQ CQ (I can copy but not read the rest), believed to be NSS — US Naval Academy transmitting for Annual Armed Forces Crossband test.

At 3:37 pm, I posted:

1934Z — 14.487 station NSS announces in voice they are listening 14.234.0 USB. Additional contacts in SSB. “It’s raining buckets here.”

Not hearing anything further, I filled  out the QSL request for — which asked for two-way contact information. I explained that I had only heard the Anapolis station, but I gave the details. Frankly, I did not hold out much hope for receiving a card, but yesterday it arrived.

As I reported elsewhere the MFJ 1020C active antenna/preselector made it possible to hear the Armed Forces Day station.

It was a very nice surprise to received the QSL card in the mail.

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Beach Boys, Good Vibrations, and HB-7 Headphones

Many thanks to SWLing Post contributor, Mark C, who writes:

Thomas,

You have posted numerous photos of radios appearing in film. I found something similar but with an interesting twist.

The link is to the YouTube clip Good Vibrations the Lost Studio Footage. Watching the Beach Boys singing that iconic musical selection is thrilling enough but I would have never guessed I would be seeing them wearing the military HB-7 and using them as studio headphones while they were performing!

Good Vibrations the Lost Studio Footage

Click here to view on YouTube.

Sincerely,

Mark

That’s just brilliant, Mark. Thank you for sharing this. I would have never guessed HB-7s would be used in a studio setting, but it certainly looks like them in the video.

I have to thank you for sharing this lost footage of the Beach Boys, too. This was new to me. I love the song, too; certainly iconic!

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