Category Archives: Software Defined Radio

Off-Grid Radio: Portable power recommendations?

This year, I have a lot of portable radio play in mind as I travel across the continent. At some point, I even plan to spend several days in an off-grid cabin on the coast.

In the past, I’ve powered my 12 VDC ham radio transceivers with a system comprised of three PowerFilm solar 5 watt foldable PV panels (see below), a Micro M+ charge controller and several gel cell type sealed batteries (a couple 7 Ah and one 20 Ah).

The system works well, but the batteries are a little heavy and unhandy when I want to hike into a remote site or play radio on the beach, for example.

In terms of receivers, my portables (like the Sony ICF-SW7600GR, Tecsun PL-660, etc.) simply use AA batteries which I charge with PowerFilm AA PV chargers (see above). My CommRadio CR-1a has an internal battery that will power it for hours at a time.

Power is much less of an issue with receivers because they’re quite resource efficient.

I mainly need a system to power my QRP ham radio gear, and that’s where I could use your experience!

Wish list

Charge controller

I need a new charge controller since my Micro M+ (no longer produced) is now being used to power a remote antenna tuner.

Of course, I’ll need an inexpensive charge controller that doesn’t produce RFI (radio interference).

It would be an added bonus if the charge controller could also charge my batteries when grid power is available.

12 VDC Battery packs

I’d like something relatively lightweight and safe.

Note: LiPo packs worry me, especially since I had one (an early GoalZero model) quite literally melt down and burn up on my bed only a few hours after bringing it back from an eight hour flight a few years ago. Scary!

Pure Sine Wave Inverter

I’d also like a small, efficient pure sine wave inverter that I I could connect to my largest battery and power my laptop for extended SDR spectrum recording sessions while off-grid.

I’d love a recommendation from someone who uses one and can confirm a model that doesn’t create radio interference while operating.

Recommendations?

Post readers: Please comment with your recommendations and include model numbers and links if possible. Thank you in advance!

SDR Touch now supports the SDRplay RSP in Beta release

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(Source: SDRplay Blog)

Good news for Android users – SDR Touch have released a beta version of their software with SDRplay RSp functionality – go to https://play.google.com/apps/testing/com.sdrtouch.sdrplay to sign up as a beta tester.

SDR Touch works on most recent Android Phone or Tablet devices.

The Icom IC-7300 vs. WinRadio Excalibur: Which do you prefer?

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[UPDATE: Read the full IC-7300 review–along with listener survey results–by clicking here.]

In the past, receiver shoot-outs in which I’ve provided sample audio for “blind” comparison––meaning, the listener does not know which audio sample is associated with which radio––have produced particularly positive feedback from Post readers.

The WinRadio Excalibur

So I’ve decided to do this for the new Icom IC-7300 transceiver. I’ve pitted the ‘7300 against a benchmark receiver: the WinRadio Excalibur.

I have a number of SDRs (software defined radios) in the shack at the moment, but I picked the Excalibur because it’s the closest in price ($900 US) to the IC-7300 ($1500) as compared to my Elad FDM-S2 ($520) or the TitanSDR Pro ($2500).

Recording notes and disclaimers

Both the WinRadio Excalibur and the Icom IC-7300 offer native digital audio recording (nice touch, Icom!). The Excalibur simply records the AF to a file on my PC’s hard drive, while the IC-7300 records the audio to an SD card which I can later transfer to my PC.

I’ve been using the Excalibur since 2012, so I’m very familiar with its recording feature. I was not, however, familiar with the IC-7300’s digital recorder, so prior to making recordings, I checked to make sure its recorded audio was a fair representation of its live audio. To my ear, the IC-7300 recorded audio was nearly identical to that of the live audio, so I used the 7300’s internal recorder rather than one of my external recorders.

Both receivers shared my large outdoor omni-directional horizontal delta loop antenna for each test.

The Elad ASA15 Antenna Splitter Amplifier

To keep the comparison on as equal footing as possible, the receivers shared the same antenna through my Elad ASA15 antenna splitter amplifier. Though the ASA15 has both 12dB amplification and –15dB attenuation, I employed neither.

The ASA15 allowed me to make the following recordings simultaneously.

In each case, I tried to set up both radios using the same filter widths, gain, AGC settings, and (as much as possible), audio level. I didn’t engage a noise-reduction feature on either rig.

Note: the only exception to the radios’ equal treatment was in the AM mode recordings, in which I used the WinRadio’s AM Sync (AMS) mode. Why? Frankly speaking, 99% of the time during which I use the Excalibur, I do employ its AMS mode as its AM mode often sounds “hot” and over-driven when band conditions are as noisy, as they were last night.

The IC-7300 does not have AM synchronous detection (AMS mode), but I felt it compared very favorably to the Excalibur in AMS mode. The IC-7300 would have easily beat the Excalibur in this test had I only used the Excalibur’s AM mode. In the end, as a shortwave listener, the goal is to compare the total capabilities of broadcast performance between the two receivers (thus using sync mode if available, to maximize broadcast listening performance).

Please vote!

At the end of this post, I have an embedded a survey in which you can vote for the sample recordings you like best. Each recording is clearly labeled to denote that it’s either from “Radio A” or “Radio B” (I had my wife draw names from a hat to determine which radio would be labeled as A or B).

Since there are quite a few recordings, I’d suggest jotting down your notes separately before completing the survey.

Or, alternately, you can open the survey in a separate window by clicking here.

And now…here’s the recordings.

Ham Radio Band recordings

The following recordings were made on the 40 meter ham radio band yesterday evening. Both radios have the same filter width: 250 Hz in CW, 3 kHz in SSB.

Weak Signal CW (40 meter band)

Radio A

Radio B

Weak/Strong SSB QSO (40 meter band)

Radio A

Radio B

Shortwave Broadcast recordings

The following recordings were made on the 31 meter broadcast band yesterday evening. Both radios have the same filter width: 9 kHz and 8.2 kHz.

Weak Shortwave AM (Radio Bandeirantes 31 meter band)

Radio A

Radio B

Strong Shortwave AM (Radio Romania International, French 31 Meter Band)

Radio A

Radio B

Mediumwave Broadcast recordings

Note that the following mediumwave recordings were made during the morning hours (grayline). The strong station is the closest AM broadcaster to my home; it’s not a blow-torch “Class A” type station, merely the closest local broadcaster.

In the “weak” sample, I tuned to 630 kHz, where multiple broadcasters could be heard on frequency––but one was dominant.

Both radios are set to a filter width of 9.0 kHz.

Strong Mediumwave AM (1010 kHz)

Radio A

Radio B

Weak Mediumwave AM (630 kHz)

Radio A

Radio B

We want to hear from you!

Use the form below to vote for the recordings you prefer in each section.

I’ll close voting at 12:00 UTC on Thursday April 21, 2016. Thank you in advance for your participation in this survey!

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A QS1R replacement in the works?

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Many thanks to SWLing Post contributor, Ken McKenzie, who noticed the following message from Phil Covington (of Software Radio Laboratory LLC) on the QS1R Yahoo group:

I am working on a replacement for the QS1R that will be less expensive, yet
use updated components. I am hoping to have them in production by the end of March.

Regards,

Philip A Covington
Software Radio Laboratory LLC
Columbus, Ohio
http://www.srl-llc.com

Ken noticed that the message was originally dated about one month ago, so I’ll follow-up with Phil and see how much progress has been made. The QS1R was a well-respected SDR that had been on the market for several years. It would be great to see an updated version on the market.

One year with the TitanSDR

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Last year, I reviewed the TitanSDR Pro by the Italian manufacturer, Enablia,. I was very impressed with not only this receiver’s performance, but also its accompanying application’s user interface. I also noted in the review that the TitanSDR is pricier than many other benchmark SDRs on the market ($1380-1970 EUR) but it is, after all, essentially a military-grade SDR that has been ported to the enthusiast/ham radio market.

I’ve been using and testing updates to theTitanSDR Pro for a year now, and I continue to be just as impressed with this receiver––and, especially, with the company who manufactures it, Enablia.

I wondered at the time of my initial review how supportive Enablia might turn out to be; I knew time would tell. Since my original review last year, Enablia has been regularly updating the TitanSDR application, adding many features requested by its users. This shows a remarkable degree of responsiveness, and I now feel safe to say that that Enablia is an exceptional manufacturer with an exceptional product.

Only recently, I received an update which added two notch filters per narrowband channel, memories that retain AGC and notch filters settings, and sessions that retain AGC settings. I understand Enablia is also preparing updates that improve upon memory management, user interface, audio defaults, as well as offering a few tweaks to the existing feature set.

Overall, Enablia developers are certainly making this signal intelligence SDR cater to the ham radio and enthusiast market even better than before.

Though I use a number of SDRs, I reach for the TitanSDR any time there are multiple-band openings since it can record spectrum and audio across the entire LW/MW/SW landscape. Unlike my other SDRs, it’s not limited to an (already generous) 2-6 MHz recording/listening window.

For example, on Thursday night I had a lot on my listening/recording plate as there were a number of band openings. I had the TitanSDR tuned to:

the 31 meter band,
the 20 meter ham radio band,
the 49 meter band (specifically monitoring South American stations), and even
the mediumwave band.

The TitanSDR was recording spectrum on the 49 meter band while I made this AF recording of the Voice of Greece on the 31 meter band (9420 kHz, starting around 00:26 UTC on April 8, 2016):

Surprisingly, all of this recording wasn’t taxing my PC, nor the TitanSDR.

The TitanSDR application is highly stable and uses resources efficiently. Indeed, in the past year, to my knowledge the TitanSDR application hasn’t crashed even once, despite my rigorous demands of it. Since it runs nearly 24/7 in my shack, on a four-year old PC (third generation i5 Win 7), that’s saying a lot.

SWLing Post reader, Tony Roper, is also a heavy TitanSDR user and recently posted this 30+ minute video demonstrating some of the TitanSDR’s new features. Note that his screen capture software produced fairly low audio, so you’ll need to turn up the volume to hear his commentary:

Click here to view on YouTube.

In short, I stand by my conclusions drawn last year in my TitanSDR review: although pricey compared to the competition, for those who can afford the price tag, the TitanSDR is a worthy hard-core DX machine that is especially useful to need a receiver with a bullet-proof front end, to weak-signal DXers, and to radio archivists like yours truly.

Mike’s overview and review of the $40 Soft66RTL3 SDR by Kazunori Miura (JA7TDO)

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Many thanks to SWLing Post contributor, Mike Ladd, for the following guest post and overview of setting up and using the Soft66RTL3 SDR:

Soft66RTL3 SDR: A low cost…Good performer direct from Japan

by Mike Ladd

Much has changed in the last 8 years in the world of SDR radios. Fast forward to 2016 and just about everyone in the hobby has heard the buzz word “SDR radio”. When SDRs first came out to the market they were all aimed at HF listening and you had two types to pick from. The first being soundcard based and the second being direct sampling. The price gap between the two were several hundred dollars. The more expensive being direct sampling. As the hobby progressed, so did the technology and the prices started to shift dramatically.

You can now purchase a TV dongle for $10.00 and turn it into a SDR. The Soft66RTL3 is basically a TV dongle but with a lot more features.

The Soft66RTL3 comes from an engineer who is no stranger to the world of SDRS. Kazunori Miura (JA7TDO) has been designing and selling many models of SDRS over the internet and shipping them direct from Japan for about 7 years. The Soft66RTL3 is his latest of model hot off his bench. This SDR is a dual input RTL-SDR with a built in 50 MHz upconverter along with 4 user selectable band pass filters that greatly increase your signal to noise ratio in the HF bands.

The frequency range of the RTL3 is from DC to Daylight (0.4 kHz to 1.7 GHz). Miura also addressed a heat issue with the previous version (RTL2) by adding a thermal pad and heatsink. RTL dongles are notoriously unstable due to overheating. In theory, the thermal pad should add frequency stability and keep drift to a minimal.

The last feature of the RTL3 is the input gain trimmer pot (see image above). The trimmer pot is for the HF side of the SDR and is already set before it’s shipped from Japan. If you would like to reduce or increase it the trimmer pot is easily accessible. I would suggest leaving it as is.

The RTL3 is broken down into two sections: the HF input side and the VHF/UHF input side.

The HF side of the SDR (above) has a red rotary encoder and trimmer pot port. The VHF/UHF side (below) has the USB Mini-B connection.

Both sides of the RTL3 terminate to a SMA-Male connection and Power comes from a single USB Mini-B cable.

Band pass filter selection

If you look at the rotary encoder (red cap cover) you will see a small notch window. The 12 o’clock position is #5 on the encoder dial. One click clockwise will take you to switch position #6 and one click counterclockwise will take you to #4. You should pull the red cap cover off to have a look and get your bearings.

The band pass filter selection is as follows:

#4 enables BPF 0.4 to 1.2MHz
#5 enables BPF 1.2MHz to 5MHz
#6 enables BPF 5MHz to 15MHz
#7 enables BPF 15MHz to 30MHz
#8 or #9 enables the VHF UHF side of the SDR

All other positions will bypass the filtering section on the HF side of the SDR.

Installation

If you already have a RTL-SDR on your system then all you need to do is swap it out with the RTL3 and change the offset of -50,000,000 in HDSDR or SDR# to listen to the HF side of the RTL3–but if this is your first SDR we will need to install 2 items: the front end app and the driver.

I will assume your system is Win-7 or better and we will be using SDR# as our program of choice to drive the RTL3. The RTL3 runs just fine in HDSDR and SDR-Console, but by choosing SDR# it will reduce our setup time considerably.

Plug in the RTL3
Make a folder on your desktop and name it SDR#
Download the latest version SDR# from www.airspy.com and copy the contents of the zip file to your newly created SDR# folder
Inside of your SDR# folder, double click on install-rtlsdr
After the batch completes, double click on the “zadig.exe” inside your SDR# folder

When you run the “zadig.exe” make sure you select “list all devices” as shown above.

The next 3 steps are:

Select “Bulk-In Interface” (Interface 0)
Make sure the proper USB device is selected (2838)
Click “install driver”

The RTL3 is now ready to be used and no further setup is required.

For a more detailed installation I would visit RTL-SDR.COM for a complete setup instructions: http://www.rtl-sdr.com/rtl-sdr-quick-start-guide

I will assume you did not have any issues setting up the ZADIG driver and now move on to using the RTL3 inside of SDR#. I will show you real world conditions that are not from any scientific standpoint.

Antenna wise, for the HF side I will be using a G5RV mini and for the VHF/UHF side I will be using a Scanntenna ST-2.

You can now launch SDR# and check the following settings (see image below).

For the VHF/UHF side of the RTL3 you will want the rotary encoder on position #9. You want the cutout in the encoder cap showing the 5 o’clock position.

Summary

I have been using this SDR for a little over 3 months. Out of all the low cost SDR’S on the market, this one gives you the most bang-for-your-buck and it is a great entry level SDR with some “Pro” features.

Pros:

Low Price
HF VHF/UHF in one package
Works with any app that supports the RTL-SDR front end
4 user selectable band pass filters for HF
Highly sensitive user controlled input RF amp
Small & very compact metal case
Dual input SMA jacks
ESD protection diode

Cons

Some intermod in the 460-470 MHz range
Inputs are on opposite sides of the SDR body

The Soft66RTL3 price is $40.00 US shipped–click here to order.

Mike, thank you so much for this excellent overview of the Soft66RTL3! I’m especially appreciative of the time you’ve taken to explain the installation process–for many, this is one of the more difficult RTL-SDR learning curves.

I’m very tempted to check this out for myself–I love the fact that this little SDR has bandpass filters.

Post Readers: I suspect Mike will monitor the comments in this post, so feel free to ask questions. Make sure to check out Mike’s website, where you’ll find more articles about software defined radios.

A $38.99 RTL-SDR with 100 Khz – 1.7 GHz coverage

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Many thanks to SWLing Post contributor, Bill, who recently shared a link to this very affordable RTL-SDR with wideband coverage.

I am not at all familiar with this model, but I do like the enclosure and the fact it has both an HF and UV antenna jack. This must be one of the least expensive SDRs on the market with HF coverage.

Here are a few details per Radioddity.com:

Features:

100% Brand New And High Quality
Using the RTL2832 idle channel, broadband connection impedance isolation transformer provides the signal to the signal receiver HF HF bands.
Increased input low-pass filter to improve noise performance of the machine. At the same time, it retains the original V / UHF band reception, creative use of studded way to achieve RTL2832 + R820t circuit board assembly and connecting circuits increases
Further improve the overall performance of the circuit.
In the homemade circuit board also surrounded, surrounded reserved some help to further develop the pads. The entire circuit is loaded inside a small aluminum to further improve the performance of the overall circuit interference by aluminum shielding.

Package Contents: