A very simple mod for your PowerMate controller

My Powermate USB sporting a white rubber band grip.

My Powermate USB sporting a white rubber band grip.

After publishing the post about my PowerMate USB controller, Mike Ladd replied on Facebook:

“Do what I did a couple of years ago and add a lobster claw rubber band to the [PowerMate] tuning wheel.”

In case you’re not familiar, Mike is referring to the thick, wide rubber bands that are placed on lobster claws to hold them shut. Mike included the following video; you can see that the rubber band fits perfectly around the top of the tuning knob, giving it a little extra grip.

https://www.youtube.com/watch?v=gtlDMSpaj4c

This same type of rubber band can often be found in the produce department of grocery stores as it’s used to hold bunches of broccoli, asparagus and other produce together.

Many thanks for the tip, Mike!

Using synchronous detection and notch filter to eliminate het noise

WinRadioExcalibur-VOG-Notch

The lighter shaded side of the AM carrier indicates a lower sideband sync lock. (Click to enlarge)

A few days ago, I tuned to 9,420 kHz and found a relatively strong signal from the Avlis transmitter site of the Voice of Greece. The broadcast was quite clear until a heterodyne (het) tone popped up out of nowhere.

I checked the spectrum display of my Excalibur to find two steady carriers located about .5 kHz off each side of VOG’s AM carrier. I assume this may have been a faint digital signal centered on the same frequency as VOG.

The noise was annoying, but SDRs (and many tabletop radios) have tools to help mitigate this type of noise.

The het tone was originating from both sidebands of the VOG AM carrier (see spectrum display above). I had planned to use my notch filter to eliminate the noise, but I had two carriers to notch out and only one notch filter.

VOG AM carrier

Synchronous detection to the rescue… 

The simple solution was to eliminate one of the carriers using my SDR’s synchronous detector which can lock to either the upper or lower sideband. In this case, it didn’t make any difference which sideband I locked to because both had similar audio fidelity and were otherwise noise free. In the end, I locked to the lower sideband, thus eliminating the het in the upper sideband.

Next, I enabled my notch filter and moved its frequency to cover the annoying het carrier in the lower sideband; I kept the notch filter width as narrow as I could to preserve VOG’s audio fidelity. You can see the notch filter location and width in the spectrum display above (the notch filter is the thin yellow line).

I should note here that the great thing about using an SDR–or tabletop receiver with a spectrum display–is that you can see where the noise is. I was using my WinRadio Excalibur, but pretty much any SDR in my shack could have handled this task.

The results? No het tone and I was able to preserve the great audio fidelity from the Voice of Greece broadcast!

Here’s a 3.5 hour recording I made after cleaning up the signal. I believe at one point in the recording, I switched off the notch filter to demonstrate how loud the het tone was:

Audio Player

Icom introduces the IC-7300

Icom-IC-7300

Icom introduced a new general coverage transceiver this year at the Tokyo Hamfair: the Icom IC-7300.

Icom has released a preliminary spec sheet (click here to download), but no pricing information yet. The IC-7300 will most likely be the least expensive Icom transceiver with a full spectrum display.

At first glance, I like the form factor and touch screen display–the panel appears to be less cluttered than many other large-display models. The ‘7300 has dedicated knobs for passband tuning and AF/RF gain (major plus in my book). It also comes with a built-in automatic antenna tuner.

I’ll post more info once Icom releases pricing and availability.

You can follow IC-7300 updates by bookmarking this link.

Paul’s Radio St. Helena Day announcements

radiosthelena

Many thanks to SWLing Post reader, Paul Walker, who writes:

I am a radio personality here in the USA as well as a SW and MW DX’er.

I appeared on the 11092.5 USB during Radio Saint Helena Day 2009 and have several short recordings, which are attached. That’s my voice doing the station identification/promotional announcements.

Sample 1

Audio Player

Sample 2

Audio Player

Very cool, Paul! It’s quite amazing to hear studio quality audio from Radio St. Helena Day as so many of us had to strain to hear their signal from across the Atlantic! Glad you were able to be a part of such an amazing little station.

I miss those Radio St. Helena Days and, though I know it’s doubtful, certainly hope the station considers firing up a shortwave transmitter again.

Guest Post: Brian’s 1974 mix tape of off-air shortwave radio recordings

HalliDial

Many thanks to SWLing Post and Shortwave Radio Audio Archive contributor, Brian Smith, for the following guest post and vintage recording:


Shortwave Radio 1974: Canada, Argentina, Spain, West Germany, Albania, utility stations

-Brian Smith (W9IND)

Want to know what shortwave radio sounded like in 1974? This 55-minute recording, recovered from a cassette, was never intended to be anything but “audio notes”: I was an 18-year-old shortwave listener who collected QSL cards from international stations, and I was tired of using a pen and a notepad to copy down details of the broadcasts. I wanted an easier way to record what I heard, and my cassette tape recorder seemed like the perfect means to accomplish that goal.

But it wasn’t. I soon discovered that it was simpler to just edit my notes as I was jotting them down — not spend time on endless searches for specific information located all over on the tape. To make a long story shorter, I abandoned my “audio notes” plan after a single shortwave recording: This one.

Hallicrafters S-108 (Image: DXing.com)

Hallicrafters S-108 (Image source: DXing.com)

Still, for those who want to experience the feel of sitting at a shortwave radio in the mid-1970s and slowly spinning the dial, this tape delivers. Nothing great in terms of sound quality; I was using a Hallicrafters S-108 that was outdated even at the time. And my recording “technique” involved placing the cassette microphone next to the radio speaker.

Thus, what you’ll hear is a grab bag of randomness: Major shortwave broadcasting stations from Canada, Argentina, Spain, Germany and Albania; maritime CW and other utility stations; and even a one-sided conversation involving a mobile phone, apparently located at sea. There are lengthy (even boring) programs, theme songs and interval signals, and brief IDs, one in Morse code from an Italian Navy station and another from a Department of Energy station used to track shipments of nuclear materials. And I can’t even identify the station behind every recording, including several Spanish broadcasts (I don’t speak the language) and an interview in English with a UFO book author.

The following is a guide, with approximate Windows Media Player starting times, of the signals on this recording. (Incidentally, the CBC recording was from July 11, 1974 — a date I deduced by researching the Major League Baseball scores of the previous day.)

Guide To The Recording

00:00 — CBC (Radio Canada) Northern and Armed Forces Service: News and sports.
07:51 — RAE (Radio Argentina): Sign-off with closing theme
09:14 — Department of Energy station in Belton, Missouri: “This is KRF-265 clear.”
09:17 — Interval signal: Radio Spain.
09:40 — New York Radio, WSY-70 (aviation weather broadcast)
10:22 — Unidentified station (Spanish?): Music.
10:51— Unidentified station (English): Historic drama with mention of Vice President John Adams, plus bell-heavy closing theme.
14:12 — Unidentified station (Spanish?): Male announcer, poor signal strength.
14:20 — Unidentified station (Spanish): Theme music and apparent ID, good signal strength.
15:16 — Unidentified station (foreign-speaking, possibly Spanish): Song, “Chirpy Chirpy Cheep Cheep.”
17:00 — Deutsche Welle (The Voice of West Germany): Announcement of frequencies, theme song.
17:39 — Unidentified station (English): Interview with the Rev. Barry Downing, author of “The Bible and Flying Saucers.”
24:36 — One side of mobile telephone conversation in SSB, possibly from maritime location.
30:37 — Radio Tirana (Albania): Lengthy economic and geopolitical talk (female announcer); bad audio. Theme and ID at 36:23, sign-off at 55:03.
55:11 — Italian Navy, Rome: “VVV IDR3 (and long tone)” in Morse code.

Click here to download the recording as an MP3, or simply listen via the embedded audio player below:

Audio Player

Brian, this is a brilliant recording–regardless of audio quality–and we’re very thankful you took the time to share it. Propagation has left something to be desired as of late, so time traveling back to 1974 has been incredibly fun. 

Post Readers: If, like Brian, you have off-air recordings on tape that you’d like to share, please contact me! Even if you don’t have the means to transfer your tapes to a digital format, I’m a part of a small community of shortwave radio archivists who would be quite willing to help.

Android tablet SDRs?

Image: screen grab from SDRtouch video

SWLing Post reader, Philip, writes with the following question:

“I want to know if you are aware of any good shortwave receivers that can be used on an Android tablet.”

I am aware of the Android SDR application, SDR Touch (see image above), but have never used it so I can’t comment on compatibility with the various SDRs on the market. I know that SDR Touch is compatible with devices that support USB host mode–but you may need to do research to see if your Android device and potential receiver are compatible. I believe most SDR Touch users connect their device to RTL-SDR dongles.

Readers: Please comment if you have any suggestions for Philip. I’m also curious if anyone has had success pairing an Android tablet to an HF-capable SDR.