Noise Gone At Last

As I wrote here in June 2016, I am very happy with my ELAD FDM-S2/SW2 SDR receiver, but there was a problem: interference from the MacBook Pro battery charger/power supply. The interference was so strong that only the strongest AM stations are above the noise.

I eliminated some of the noise when I reconnected an antenna switch to ground (after it had become mysteriously disconnected), but that did not eliminate the noise completely.

I installed ferrite cable clips on the charger's cable, but that made no difference. I wrapped the cable 20 times around a toroid ferrite core, but that made no difference.

The only solution that worked was to use the ELAD-MacBook Pro combo without the battery charger. This gives me a few hours operating without the interference, but sooner or later, the battery would need to be recharged.

A few days ago, I was using my MacBook and the battery was getting low. I was too lazy to go upstairs to fetch my charger, when I noticed my daughter's MacBook Air battery charger/power supply on the kitchen table unused. So I decided to try it even though it is a different model than the one bundled with my MacBook Pro (45W vs. 85W). Despite the difference, it charged my MacBook Pro without working up a sweat.

I wondered how my daughter's 45-watt charger would perform with the ELAD receiver, so I took it to the radio shack, made all the connections and voila! the 45-watt charger was clean. No noise at all!

I did a little Googling to see if there were any gotchas about using the wrong charger with my MacBook Pro and found this, which claimed that the charger, "will not charge the machine at all while in use, and will only trickle-charge the machine while asleep."

That was just the opposite of my experience, but to make sure I was correct, I used the 45-watt charger while running the ELAD FDM-SW2 software and it took my MacBook Pro's battery from 75% to 99% in about an hour.

That was good enough for me. I Googled the 45-watt charger, found it for sale here for $55 and ordered it as fast as PayPal could handle it.

Gone

Thank you for your suggestions on how to fix the interference problem I encountered while using the ELAD FDM-S2 SDR receiver with my MacBook Pro computer.

The source of the noise seemed to be the computer's battery charger/power supply, but all my attempts to fix the problem failed until I noticed that my Heath coaxial switch was not grounded. I assume its connection to ground had been disconnected while I was rearranging the furniture and I forgot to reconnect it.

Reconnecting the switch to ground made a big difference and eliminated most of the noise on the AM/MW band.

Nine New Ones!

Tuning around the AM band with my new ELAD FDM-S2 SDR receiver last week, I logged three new stations:

- WGYM on 1580 kc in Hammonton, NJ, transmitting 1 kW 168 miles to the SSW.

- WACK on 1420 kc in Newark, NY, transmitting 500 W, 232 miles to the WNW.

- WQFG689 on 1710 kc in Jersey City, NJ, transmitting 10 W, 85 miles to the SW. WQFG689 is a TIS for Hudson County, NJ.

Friday night, I tried recording the whole AM band for two minutes at 10 PM EDST. I spent a few hours listening to the recording and logged six new stations:

- WNEB on 1230 kc in Southbridge, MA, transmitting 1 kW, 73 miles to the NE

- WICH on 1310 kc in Norwich, CT, transmitting 5 kW, 45 miles to the WSE.

- WEMG on 1310 kc in Camden, NJ, transmitting 250 W, 162 miles to the SW.

- WWRU on 1660 kc in Jersey City, NJ, transmitting 10 W, 85 miles to the SW.

- WTTM on 1680 kc in Lindenwold, NJ, transmitting 1 kW, 162 miles to the SW.

- CKAT on 600 kc in North Bay, Ontario, 455 miles to the NW.

All were heard using an 80 meter inverted Vee antenna.

I am very happy with my new radio, but there is a problem: interference from the MacBook Pro battery charger/power supply. The interference is so strong that only the strongest AM stations are above the noise.

The cable between the charger and the computer is the problem because the noise disappears completely when I disconnect the cable from the computer even though the charger is still powered.

I installed ferrite cable clips on the cable, but that made no difference.

I wrapped the cable 20 times around a toroid ferrite core, but that made no difference.

One solution that works is to use the ELAD-MacBook Pro combo without the battery charger. This gives me a few hours operating without the interference, but sooner or later, the battery will need to be recharged.

Anyone have any other solutions?

Running Windows and Mac OS X in Parallel

WGYM: My first new logging with the ELAD FDM-S2 SDR Receiver.

I have owned Macintosh computers since they were originally released in 1984. Way back when, I had a clunky DOS emulator on one of my desktop Macs. I cannot recall why I bought it because I don't remember using it much... maybe because it was so clunky.

Windows emulators/enablers for the Mac have been around for awhile. I have never had a need for one until now, so I had not paid much attention to them and had to educate myself quickly.

I read a few articles comparing what was available and found myself on Parallels' website where there was a link to download and try out their enabler for 14 days. I downloaded and installed the enabler without a problem, but there was not much I could do with it because it needed Windows.

My computer at work runs Windows 7, so I am familiar with that OS and figured I would be more comfortable running 7 on my Mac rather than another version of Windows. But I asked around about Windows 10 because the Parallels enabler was being touted as ready for Windows 10 and folks on the Yahoo ELAD group (elad_sdr_en) said the FDM-S2 software ran fine on Windows 10. So I ordered Windows 10 from Amazon and received the installation USB flash drive two days later.

There were no gotchas installing Windows under Parallels, nor installing the FDM-S2 software onto Windows under Parallels.

I connected the ELAD FDM-S2 receiver to my MacBook Pro, powered up the receiver and started the software. The software started up on my Mac just as quickly as it started up on the Windows laptop I tried it out on and has run perfectly under Mac-Parallels-Windows since I have installed it four days ago.

Some observations:

• I can run Windows 10 and Mac OS X simultaneously, which is something I did not expect.

• Windows 10 starts up faster on my Mac than does Windows 7 on the Lenovo laptop at work.

• The FDM-S2 software crashed a number of times on the Lenovo laptop running Windows 7. It always crashes if I try to expand the GUI window beyond a certain point and it has crashed numerous times while playing back on-the-air recordings. So far, the FDM-S2 software has not crashed on my Mac.

• I have a shortcut on my Mac's desktop for the FDM-S2 software, which loads Parallels, Windows 10 and the FDM-S2 software with just one click.

But Cupertino, we have a problem!

It works, so, so far, so good!

I bought an ELAD FDM-S2 SDR Receiver at Hamvention.

Its software is Windows-based, but the gent in the ELAD booth assured me that it would run on a Mac under a Windows emulator. Even if it did not, I had some old Windows laptops at my disposal that I could use, although I preferred to run it on my Mac because empty space on my radio desk was lacking,

Back at my Hamvention hotel room, I checked the contents of the box containing my purchase. In addition to the receiver, there was a USB stick containing the SDR sofware and documentation, two BNC-to-SMA adapters to mate the receiver's HF and VHF SMA connectors to antennas, a USB cable, a USB Y-cable, a cloth bag for storing and transporting the receiver and four stick-on feet to attach to the receiver.

After returning home and catching up, I installed the software in a laptop running Windows 7. The installation was quick and easy without any problems.

I connected the receiver to the laptop and to my 80-meter inverted Vee antenna, then I powered up the receiver and started the software. The software loaded quickly and soon I was staring at an impressive graphical user interface (GUI), but I could not hear a thing and the display indicated that nothing was being received, as seen in the image above.

My first thought was "dead on arrival" and I was not a happy camper. Thumbing through the manual did not provide a solution and then I noticed an on/off button in the lower left corner of the GUI! I clicked it once and, voila!, I could hear plenty ― what a relief!

Without reading the manual, I fumbled around and managed to tune the receiver to the AM broadcast radio band. My first impressions were that the receiver was as sensitive and perhaps more sensitive than my Elecraft KX3 on the AM band.

That was promising, but I did not play with the receiver much because I wanted to concentrate on getting the software up and running on my two-year-old MacBook Pro Retina 15-inch laptop.

At Hamvention 2014

The 2014 installment of the Hamvention was a memorable one.

I have been attending Hamvention regularly since 1978 and this year, we had some of the worst weather I have ever seen at Hamvention... even worse than when the event was held a month earlier when the potential for lousy weather was higher.

It rained, sleeted and hailed on Thursday, Friday and Saturday. Morning temps during those days started in the high 30's and did not get much above 50. I knew precipitation was in the forecast, but I did not expect it to be so cold and I did not dress appropriately. Luckily, I had a hoody to keep me warm when needed.

My family likes to watch my progress to and from Dayton via APRS, but I do not have a ham radio installed in my vehicle, so APRS was not an option. However, I do have an iPhone and there are some APRS apps for it. So I bought an app called OpenAPRS and it filled the bill as can be seen by my tracks as displayed on aprs.fi  above.

As I wrote in my previous blog post, "I always staff the TAPR booths on Hamvention Fridays and Saturdays, so if you make it to Hamvention this year, stop by... and say “Hi.” Well, at least one of you did just that: Dave = WA1OUI, who has been one of my most loyal readers and is also a long-time friend going back to the FM repeater wars of the 1970s. Dave was working in one of the ARRL booths just up the aisle and I returned the favor and stopped by his booth!

I ran into a lot of other old friends during the weekend --- not sure if they read this blog or not. Some showed up at the TAPR booth and some I bumped into on the convention floor; folks like Al = N8DHF, Bob = WB4APR, Craig = K1QX, Dave = K1ZZ, Guy = KC5GOI, Harold = WJ1B, Joe = K0NEB, Rich = W2VU, Steve = N8GNJ, Tom = K3IO and many others.

The TAPR booth was very busy all weekend, busier than its been at recent Hamventions probably because we had a lot to show this year. John = N8UR was showing his high precision timing projects, Jeremy = NH6Z and Scotty = WA2DFI were demonstrating SDR, Mike = No-Call-Yet had his HackRF attracting a lot of attention, Chris = KD2BMH was with his WhiteBox SDR handheld transceiver, and there was a big crew staffing the digital voice demo. I fielded packet radio and APRS questions and filled in at the cash register and elsewhere while others took breaks.

Touring the Hamvention floor on Saturday, I stopped by the booth of the Society of Amateur Radio Astronomers. Since I dabble in both radio and astronomy, I thought that the booth would have something that interested me and I walked away with a radio telescope kit to receive signals from Jupiter, the Sun and the galactic plane. I will have more to say about this after I build the kit and get it on the air.

I hate the drive to and from Dayton, but I am already looking forward to doing it again next year!

$20 Multimode Software Defined Radio

By Mike Schaffer, KA3JAW

For this specialized piece of equipment, you will not be familiar with the manufacturers' nameplates as they are not your popular ham radio companies such as Alinco, Kenwood, Yaesu, Icom, JRC, MFJ or WinRadio. To date there are three company manufacturers: Ezcap, Compro and Terratec, along with other no brand clones.

These devices have been used in Western Europe to watch terrestrial Digital Video Broadcasting (DVB-T) since 1998. These 2.75" (L) x 1.0" (W) x 0.5" (H) 0.7 ounce dongle (stick) devices connect to your computer via a USB 2.0 port.

They are useless in North America as we use a different standard called Advanced Television System Committee (ATSC) for digital transmission over terrestrial, cable, and satellite networks. However, they can be adapted as Software Defined Radios (SDR) for ham radio for the 6m (50 MHz), 2m (144 MHz), 1.25m (222 MHz), 70 cm (420 MHz), 33 cm (902 MHz), and 23 cm (1240 MHz) on some models.

There are two major chip sets built into the STL-SDR dongle: RF silicone tuner and the DVB-T COFDM (Coded Orthogonal Frequency-Division Multiplexing) demodulator.

Elonics, a global leader in RF technology headquartered in the United Kingdom since 2003, has an E4000 multi-standard CMOS terrestrial RF silicon tuner designed to interface directly to a digital demodulator and contains a fully integrated LNA, programmable RF filter, and RF mixers providing superior real world performance. The front end tuner covers the frequency range from 64 - 1700 MHz. However, reports have confirmed they can be made operable from 50 - 2200 MHz with a 150 MHz gap from 1100-1250 MHz on some models.

The heart of the E4000 is an innovative DigitalTune architecture, which allows the user to adjust the performance of the tuner for optimum linearity or noise figure according to significantly improve reception quality.

The demodulator is a Realtek RTL2832U high-performance DVB-T COFDM that supports a USB 2.0 interface with an 8-MHz bandwidth at an IF (Intermediate Frequency) of 36.125 MHz, low-IF of 4.57 MHz, or Zero-IF output using a 28.8 MHz crystal and includes FM/DAB/DAB+ radio support. Embedded with an advanced ADC (Analog-to-Digital Converter), the RTL2832U features high stability in portable reception.

The state-of-the art tuner features proprietary algorithms including superior channel estimation, co-channel interface rejection, long echo channel reception, and impulse noise cancellation, and provides and ideal solution for a wide range of applications for PC-TV, USB dongle and MiniCard/USB, and embedded system via USB interface.

The SDR/GUI (Software Defined Radio/Graphical User Interface) application software is called SDR# (pronounced as SDR Sharp) and was authored by Youssef Touil in C# programming language. It is being offered as freeware (donation supported) for non-commercial, educational use. This software is a high-performance, fully-featured SDR capable of handling sample rates from kHz level sound cards up to multi-hundred MHz dedicated samplers, thanks to it's multi-core architecture. The application can demodulate NFM, AM, LSB, USB, WFM, DSB and RAW modes. 

What makes this SDR fun to use are the two Fast Fourier Transformation (FFT) display modes: Spectrum Analyzer and Waterfall. FFT is a clever algorithm which can be used to transform a signal from the time domain to the frequency domain.

Youssef's website is http://www.sdrsharp.com. Feel free to ask questions on his webpage, SDR# Yahoo! group or  #sdrsharp@freenode.

A video tutorial of the installation process by David Savidge, AF5DN, is here:
http://www.youtube.com/watch?v=MFqBj8gV0k4

And here is a video from Andy, M6PNP, performing an RTL-SDR 2-meter band scan: http://www.youtube.com/watch?v=YjqBn-LEx9Y

So where can you purchase this cutting-edge technological breakthrough product? The answer is eBay or similar on-line auction websites. Since the product comes directly from China or Hong Kong, expect to wait two to three weeks for mail delivery using free shipping.

By the way, the dongle also comes with a portable magnetic base telescopic antenna and USB cable.

Bonus: If you get tired of listening to the ham radio bands, you can tune-in to the FM broadcast band from 88 – 108 MHz in the WFM mode.

Minimum System Requirements:

• One available USB 2.0 port
• Pentium 4 CPU
• 512 MB RAM
• Graphic card supporting Direct X 9.0C
• 1 GB HDD space
• Windows XP/2000, Vista, WIN7, Linux

Notes:

1. The product comes with application software on a CD-ROM. You will not need it as you will use the SDR# (SDR Sharp) in its place.
2. Since they are intended for the Western European market, the antenna socket on the dongle is a 50 ohm female Belling-Lee IEC-16902 (Din) not the North American  75-ohm F-type. So, you will need a Belling-Lee-to-F cable connector adaptor to connect to the antenna.

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This week, Surfin’ scopes out a real deal for the do-it-yourself ham radio crowd.

Surfin: Negotiating the HPSDR Highway

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Surfin’: A New “Old” User Interface for SDR

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Surfin': You Get What Your Pay For -- Learning the Hard Way

A freak accident --- that is the only way to explain it!

Read all about it in this week's installment of Surfin'.

Surfin’: Send APRS Messages via HF PSK and GMSK

This week, Surfin’ looks at new HF APRS applications originating from the UK.

Surfin’: iPhone Gets Software Defined Radio

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Surfin': Hamming on the Edge

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