Category Archives: Reviews

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

RTL3

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.

Soft66RTL3-board-001 Soft66RTL3-Board 2 Soft66RTL3-board

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.

RTL3-TrimmerPot

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.

Soft66RTL3-encoder

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.

Soft66RTL3-back

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

Soft66RTL3-BandPassFilter

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.

ScreenShot-SDR

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

screengrab

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

ScreenGrab-Window

The next 3 steps are:

  1. Select “Bulk-In Interface” (Interface 0)
  2. Make sure the proper USB device is selected (2838)
  3. 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).

SDRSharp-Settings

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.

Jay Allen updates his AM radio shootout

Jay-Allen-PortablesMany thanks to SWLing Post contributors Ron, Vimal and Phil for noting that Jay Allen has updated his excellent AM radio shootout. Click here to read his full post.

Happy to see that the Panasonic RF-2200 remains his reference AM rig. I must agree: it’s the best portable I’ve ever used on the mediumwave band. I’m so glad I snagged a ‘2200  on eBay last year.Panasonic-RF-2200-3Tuning the RF-2200 in the field makes me feel like some sort of Cold War spy.Panasonic-RF2200-MtMitchell

A radio with fortitude and purpose.

James adds an LM386 amplifier kit to his Heathkit GR-150

Heathkit Explorer Jr. Completed w. screwdriverMany thanks to SWLing Post contributor, James Surprenant (AB1DQ), who shares this update to his review of the Heathkit Explorer Jr. TRF AM radio receiver kit:


With regard to the Heathkit TRF AM receiver kit, I did indeed build my LM386 amplifier.

I was planning on home-brewing it from scratch as the chip is pretty much all you need and there are various proven schematics for the circuit, but in the end I went with a small kit from Nightfire Electronics for $10 plus $5 shipping that I found on Amazon.com.

It was a bit cheaper to buy it in kit form, of course, and then there was the convenience of having all the parts in one place.

Here is a photo of the kit as advertised on Amazon

kit

And here is my build with the Heathkit…

Heathkit + LM 386

I modified the kit to add a 3.5mm input jack, replacing the RCA jack that came with the kit, to make it easier to plug into the Heathkit radio.

I deliberated whether to install the audio amp into the Heathkit cabinet drilling out a couple of holes for the pot shafts. It all would have fit and I could have easily mounted the 3″ 8 ohm speaker to the back panel of the Heathkit radio. In the end, I decided to keep the radio original and mounted the amplifier board on a small piece of wood I found at a hobby store and decided to leave it all exposed. It works well, all things considered.

(Click here to view video on Facebook.)

It worked well and per my original review on SWLing Post, I feel Heathkit should have included such a little amp in the kit – it makes a big difference.


Many thanks for the update, James! That little LM386 amp kit seems like an affordable addition for any receiver lacking an amplifier or adequate audio amplification.

Larry’s review of the CountyComm GP5/SSB

Many thanks to SWLing Post reader, Larry Thompson, who shares his review of the CountyComm GP5/SSB:


GP5SSB-Front

Been having a ton of fun with my new toy, the tiny survivalist radio, the CountyComm GP5/SSB receiver. $74.95 with free heavy duty cordura case with metal belt clip (normally $17.95). Also purchased 2 spare whip antennas @ $6.00 ea. The unit arrived promptly
in just 5 days from CA.

The radio is manufactured by Tecsun and is similar to the Tecsun PL-365, but re-engineer end to military standards for use in embassies and military installations around the world. The case is a heavy plastic that feels like anodized aluminum.

It’s about the size of a small TV remote control, taller than a cell phone, and about 1/2 the width of an iPhone.

Very, east intuitive menus. Incredibly sensitive to dx, relatively good selectivity. A great radio to throw in your travel bag or briefcase. So small that no one, especially customs, TSA, etc would even suspect it is a shortwave receiver with SSB capabilities.
I live in a very highly QRM and RFI interference zone.

I’m in the central city, in an old 1920’s hi-rise, with high power tension lines right next to the building.

Lots of QRM from the elevator motors, etc. Having a good antenna option is a challenge.
I’ve resorted to a stealth longwire antenna, strung out my 5th floor window. It’s 50′ of #16 black insulated copper stranded wire, weighted by a medium size galvanized carriage nut. It seems to work well.

I also use a Magic Wand shortwave antenna, a type of broomstick antenna with 23′ of lead-in, available from Lowbander on eBay.

My main receivers have been a Sony ICF-SW7600GR dual conversion receiver and the SRDPlay. In the past, I have listened to dx with some really outstanding receivers, including a Nordmende Globetrotter, a National NC-183D, a Japan Radio JRC-525′ and a Yaesu FT900AT transceiver. The later two were computer-controlled using TRX-Manager software.

In just 4 days, I can’t get over the sensitivity of the CountyComm GP-5/SSB and it’s ability to pull in stations. So far, it’s far superior to the Sony or SDRPlay.

Digging into the specs, it is a direct conversion receiver, using a DSP si47XX microchip from Silicon Labs to digitize the analog AM/FM broadcasting signal base on modern software technology and radio principles. The direct conversion circuitry can highly improve a radio’s sensitivity, selectivity, S/N ratio and anti-interference capabilities. Direct conversion using software is far superior to a double or triple conversion traditional IF circuitry. This must explain why the unit is so amazingly sensitive!

I can hear things on this unit that I can’t even begin to hear on the Sony or the SDRPlay. The FM reception and sound with earphones is amazing and LW and AM reception is equally sensitive. I can easily get WLW Cincinnati 700 kHz in the daytime here in St. Louis!

There are 550 preset memories: 100 for AM, 100 for FM, 100 for SSB, and 250 for SW. You can scan the memories or scan the bands in various ways. You can also use the Auto Tune Storage function to store memories.

Something I really enjoy is the Easy Tuning Mode function. The ETM function allows you to tune into stations easily and temporarily store them into the ETM storage. 100 stations for FM/MW and 250 for SW. Scanned stations will not be stored in the regular 550 memories, but will remain in the ETM temporary storage until the next time you do an ETM scan.

This is a great feature for travel. When you are in a different city, you can perform the ETS function and this will not delete any of the stations already in the memory.


Thanks for sharing your review, Larry. I use the GP5/SSB all of the time–it stays in one of my vehicles and I often use it for walks, picnics, camping and even a little parking lot DXing.

I suspect if your SDRplay RSP was hooked up to an antenna that could better mitigate your local QRM, you’d find it outperforms the GP5/SSB. The great thing about portables, though, is that you can simply take them to areas with low noise levels. It’s just a matter of finding the right location!

The CountyComm GP5/SSB is a very handy portable. Thanks again! 

The CountyComm GP5/SSB can be purchased from:

The Tecsun version, the PL-365, can be purchased on eBay (though be aware that some sellers have BuyItNow prices almost two times the price of CountyComm).

Review of the Kaito KA108

Kaito-KA108-Front-2

Recently, I learned about a new portable by Kaito Electronics: the Kaito KA108. While there are a number of compact portables on the market, the KA108 really caught my attention because it features a built-in digital recorder. Which is to say, you can listen to a station on shortwave, press a button, and the KA108 will record it to a MicroSD card. Pretty cool, right? It’s also the first shortwave portable I’ve ever known that offers a scheduling feature for recordings.

In the past there have been a few shortwave portables with digital recording capabilities, but most of these have been plagued with poor performance. So this time, I had my fingers crossed that Kaito might have produced a winner.

Having used the KA108 for several days now, my initial review follows, with a focus on shortwave as well as mediumwave performance.

User’s Manual

The KA108 actually ships with two manuals: a quick start reference guide and a proper highly-detailed user’s manual.

Kaito-KA108-Unboxing-3

The manual is written in English and is quite descriptive, despite a number of spelling and grammar errors that should have been caught before going to print. It’s obvious that Kaito didn’t hire a native English speaker/professional editor to check their copy.  (I don’t understand why a company would go to the expense to produce a manual without having it professionally edited…Kaito, please take note!)  Fortunately, these spelling and grammar errors, while annoying, can be overlooked and/or deciphered by most English-speaking readers.

Tuning

Kaito-KA108-Side3

On the plus side, the KA108 sports a full number keypad for direct frequency entry. This makes tuning to a known frequency a very simple process––with one exception (see below). There’s also a tuning wheel on the right side of the radio.

Kaito-KA108-Keypad

Note where the “0” is placed on the keypad: why the change?

Using the keypad requires some getting used to, however. Most of us––myself included––are familiar with traditional numeric keypads, but the KA108 inexplicably changes the game plan: as you can see above, the “0” button is located on the lower right side of the main keypad. So it took me a few hours of use before I could reliably key in a frequency without looking at the radio.

In my humble opinion, Kaito should have moved the number pad up one row, positioned the “ATS” button to the lowest row on the left, the “0” button to its immediate right, and completed the bottom row with the “Rewind/Play/Fast-Forward” buttons.

Another annoyance––and this is a big one for me–-is that the KA108 has extended muting between frequency changes. It makes band-scanning a frustrating experience. I made a short video demonstrating this:

Audio

DSC_3495The KA108 is designed around a very innovative small speaker with an acoustic chamber that significantly boosts bass response. This is the same speaker used in the Melson S8 that I reviewed some time ago.

The audio fidelity is excellent on FM, and when playing back a full-fidelity digital recording. Unfortunately, when tuned to the AM broadcast (mediumwave) band or to the shortwave bands, the KA108 falls short; the bass response actually becomes an impediment to listening.

In a nutshell: the KA108 audio has issues. A further explanation of the KA108’s audio is described in the performance notes that follow.

FM Performance

On a positive note, the Kaito KA108 has respectable FM reception. I was able to receive all my benchmark FM stations with little trouble, and the KA108 maintained a strong lock on all signals.

And as mentioned above, KA108 audio via the built-in speaker is much better on FM than on any other band. Indeed, on FM, the KA108 produces rich, full-fidelity audio that can easily fill a room. Audio is similar to that of the Melson M7 and the Melson S8.

If you’re seeking a nice FM portable with robust audio, you’ll enjoy the KA108.

Shortwave Performance

Kaito-KA-108

I’m quite disappointed with the KA108’s shortwave performance.

Almost immediately after unboxing the KA108, I inserted a battery, walked outdoors, and tuned through the 31 meter band.

Other than a couple of blow-torch North American private broadcasters, I heard…nothing. It was during this first band scan that I realized how annoying the tuning mute could be. And the audio, meanwhile, sounded muffled and garbled: I assumed that there was some local interference, and simply turned the radio off, hoping the following day would produce a change for the better.

The following day, I spent a great deal of time with the KA108 on the air, and compared it with the Eton Traveller III and the Tecsun PL-310ET––both capable, similarly-priced compact DSP radios.

Sure enough, when compared with other portables, the KA108’s reception is, sadly, rather poor.

At first I thought it might be an issue with receiver sensitivity, but the KA108 could receive almost every station the Traveller III and the PL-310ET could receive. But the audio was so muffled on the KA108, even with  the use of headphones, that spoken word was hard to interpret. Additionally, the over-active AGC (Automatic Gain Control) meant that audio levels were all over the place. That combination makes for fatiguing listening.

Volume level indicator.

Volume level indicator.

Over the next few days with the KA108 on shortwave, I drew a few conclusions.

After recognizing that the audio fidelity did not improve significantly when using headphones, I realized that at least three factors are having a negative impact on shortwave audio, as follows:

  1. The default AM bandwidth is too narrow for broadcasts, and cannot be adjusted
  2. The AGC setting is over-active and causes audio pumping; it, too, cannot be adjusted
  3.  Portions of the shortwave bands are polluted by internally-generated noise/interference

This combination makes for sloppy shortwave performance.

To save time in making the KA108’s comparison information readily available, as well as to indicate actual speaker performance, I decided to take a few quick comparison videos not with the KA108 or an external mic but simply with my smartphone. While my phone’s microphone is somewhat limited, I believe you’ll be able to observe the  inherent problems with the KA108.

I compared the KA108 with the Traveller III in each video.

In the first comparison, I tuned to Radio Exterior De España on 9690 kHz, as you’ll see. The signal was marginal or relatively weak at the time:

(Click here to view the video on YouTube.)

Next, I tuned in a very strong shortwave signal from Radio Havana Cuba on 11,670 kHz:

(Click here to view on YouTube.)

Finally, later in the afternoon, I tuned to All India Radio on 9,445 kHz––again, a marginal signal:

(Click here to view this video on YouTube.)

Mediumwave Performance

Mediumwave (a.k.a., AM broadcast band) performance is very similar to shortwave performance.

In this video, I’ve tuned to an AM station located twenty-five miles away on 1600 kHz.  The KA108 can receive the station, but audio is not pleasant and the AGC is, yet again, overactive. I’ve noticed that the mediumwave band is plagued by more internally-generated noise than are the shortwave bands.

(Click here to view this video on YouTube.)

Note that YouTube’s copyright checking system flagged my video because it recognized the song being played in the background on WTZQ. I believe this easily qualifies as fair use since the clips are short and it’s an off-air recording with dialog on top. I’ve disputed this, but YouTube may choose to delete this video.  In anticipation, I’ve saved the audio from this video–you can listen to it by clicking here.

In a nutshell, AM performance on the Kaito KA108 is frankly poor. Even when I tuned to strong local stations, the audio sounded muffled and distorted, much as in the Radio Havana Cuba example above.

So you can forget about using the KA108 for mediumwave DXing.

MP3/WAV Playback and recording

There are some redeeming virtues with the KA108, however.  Here’s a positive: digital playback with the KA108 is fantastic. I’ve played a wide variety of audio files on the KA108, and am very impressed with its on-board MP3/WAV player. While audio characteristics unfortunately cannot be adjusted––i.e., there’s no equalization––I find the default audio settings well-balanced for both music and voice.

The KA108 has a dedicated MicroSD slot and a covered USB slot on top of the unit.

The KA108 has a dedicated MicroSD slot and a covered USB slot on top of the unit.

Recording directly from shortwave and mediumwave is also quite good. I believe its on-board recorder is perhaps the best I’ve tried in recent portables; it’s a marked improvement over that of the Kaito KA29, for example. It seems to capture the receiver’s produced audio well, with only a slight, high-pitched “hiss” injected in the audio, though this is not a major distraction.

Sadly the main distraction is that the recorder is recording audio, as I’ve outlined above, from a sub-par receiver.

Still, as an MP3/WAV player, it’s brilliant, and boasts excellent audio.

Summary

Invariably, all radios have strengths and weaknesses; here’s a list of my notes from the moment I put the KA108 on the air:

Pros:

  • Great portable size
  • Clear back-lit display
  • Numerous recording and playback features
  • Audio via MP3 or headphones is strong, considering the small speaker with acoustic chamber provides more bass response and volume than comparable portables (see con)
  • Excellent FM reception
  • Excellent MP3/WAV playback with well-balanced audio fidelity
  • Recorder schedule function
  • Alarms and sleep timers easy to use
  • Dedicated MicroSD and USB slots on top of chassis

Cons:

  • Mediocre sensitivity on SW and MW
  • Internally-generated noise on MW and SW
  • Audio (via built-in speaker) is:
    • too bass-heavy, lacks treble on MW/SW
    • garbled and mushy on MW/SW
    • “hot” and often splatters/distorts when signals are strong
  • Tuning
    • extended mute between frequency changes
    • no “scan to next station” function (only ATS)
  • Odd numeric keypad layout
  • Any local RFI garbles reception even further on SW/MW
  • No SSB (in fairness, few radios in this price class have SSB)
  • Antenna swivel to the front somewhat blocked by the radio’s chassis
  • No backstand

Conclusion

I really wanted the Kaito KA108 to be a strong––or even average––performer. Why? Because, like many of you, I would love to have a capable shortwave/mediumwave radio with built-in digital recording and playback.

Kaito-KA108-AM

Sadly, the KA108 falls short on multiple levels.

Concerned that I might have simply received a defective unit––as I did when I reviewed the Sangean ATS-405––I contacted Kaito Electronics USA. I mentioned my disappointment with the radio’s performance, and detailed the negatives mentioned in this review.

I asked Kaito’s technician if I might have received a defective unit? He responded that my experience seems to be the norm with this particular production run. He, too, had noted muffled/garbled audio on shortwave and mediumwave. Per his request, I sent a detailed list of the KA108’s shortcomings with suggested fixes. He is planning to send this to Kaito’s current manufacturer in China.

The KA108’s poor performance issues would likely be mitigated to a great extent, if the manufacturer would simply make the following adjustments:

  1. Widen the AM bandwidth
  2. Tweak the AGC for greater stability
  3. Adjust the audio settings for the AM mode
  4. Minimize/shorten muting between frequency changes
  5. Improve internal shielding and grounding
  6. And while they’re at it, have the radio manual edited by a native English speaker

Since this is a DSP-based radio, I imagine the first four adjustments can be made via firmware upgrades.

Time will tell if the second production run of the Kaito KA108 improves on the first.  Fingers crossed…!  Kaito, we’d like you to succeed on this score.

Again, many thanks to Universal Radio for supplying me with a KA108 for this review.