Category Archives: Manufacturers

Very Scarce Kneisner + Doering KWZ-30 DSP Receiver Surfaces on Ebay

Hailing from Germany, the KWZ-30 communications receiver was one of the first DSP receivers available. This collectable and high performance receiver is rarely seen for sale, but one is now available for a $1890.00 Buy-It-Now price from a Russian Ebay seller. Even with the few dings visible on the radio’s case, it’s likely worth the asking price to a collector.


The extensive Fenu-Radio web site has a nice capsule review of the KWZ-30, including some excellent photos.

At the $1890.00 price of this KWZ-30, you could buy a dozen SDRPlay receivers, or roughly a couple of the highly rated Perseus SDRs. Assuming available funds, is the KWZ-30 a receiver you would add to your radio shack? If so, why… or why not?

Guy Atkins is a Sr. Graphic Designer for T-Mobile and lives near Seattle, Washington.  He’s a regular contributor to the SWLing Post.

The new LNR Precision LD-11 transceiver is essentially general coverage


A couple weeks ago, LNR Precision sent me their new LD-11 Digital Direct Conversion QRP transceiver on loan for review.

The LD-11 is basically a small, tabletop SDR transceiver. It’s like a miniature, simplified version of the Icom IC-7100 I’ve also been evaluating.

The LD-11 is an all-mode and all-band transceiver–meaning, it includes SSB, CW, CW-R, Digi, AM and FM modes on all amateur radio bands (160 – 10 meters).

Though the LD-11 isn’t advertised as having a general coverage receiver, it will indeed tune the entire HF band.

You do this by entering the LD-11’s administration mode. LNR describes this in the LD-11 product manual, but suggests you contact them for help the first time you do this. In the admin panel, you’ll find functions that allow you to set the band edges on each amateur radio band.

For a preliminary test of broadcast reception, I moved the lower band edge of the 30 meter ham radio band to 8.2 MHz.

LNR-Precision-LD-11-front panel

After saving the settings and re-starting the LD-11 in normal operation mode, I could then tune the entire 31 meter broadcast band on the LD-11.

Hypothetically, you could either widen each amateur radio band to include adjacent broadcast bands, or you could simply set one of the ham bands to include the entire HF spectrum. To make it easier to navigate and tune through the bands, I’m choosing the former method over the latter.

Since the LD-11 has a proper AM mode, broadcasts sound great–especially via headphones!

Proper AM filters for broadcast reception!

Better yet?  The AM filter width can be widened to an impressive 9.6 kHz! Woo hoo!


The LD-11 has four filter slots: F1, F2, F3 and F4.

The F1-F3 slots can be set to a fixed user-defined widths (common widths are default).

F4 can be altered to any available filter width without having to enter the admin mode of the transceiver. Simply press the “F” (blue function button) and the FILTER button simultaneously and use the encoder/tuning knob to specify the filter width in .1 kHz steps. Pressing the F and FILTER button simultaneously again, will save your filter width for the F4 position.

I’ve been using the F4 filter position for widths between about 8.2 and 9.6 kHz in AM.

It’s still early days with the LD-11, but I’m enjoying this little transceiver immensely. It reminds me of one of my favorite QRP transceivers of yesteryear: the Index Labs QRP Plus (though the LD-11 is much smaller, more versatile and has a much better front end than the QRP Plus!).

LNR Precision sold out all of their first run LD-11 units within moments of having announced availability. I’m willing to bet they’ll bring a few LD-11s to the upcoming Dayton Hamvention, though.

Check inventory status and view LD-11 details on LNR Precision’s website. 

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


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.


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.


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.


  1. Plug in the RTL3
  2. Make a folder on your desktop and name it SDR#
  3. Download the latest version SDR# from 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


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


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:

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.


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.


  • 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


  • 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.P. Richards’ 1939 thesis on the Crosley WLW Model Super-Power Radio Receiver


In response to our recent post about the Crosley WLW Super-Power receiver, SWLing Post contributor, Larry Hagood, writes:

A photo of Dr Richards from the class of 1927.

A photo of Dr Richards from the class of 1927.

I am an EE student at Oklahoma State (Formerly Oklahoma A&M)–the school where the designer of the WLW [Super Power receiver], Amyle Richards, got his BSEE in 1927.

[Richards] wrote and submitted a masters thesis on the design of this radio, which earned him a PhD!).

I found a picture of him in the Engineering South building and found him in the 1927 yearbook in the library.

Anyway, the archive department located his paper on the WLW and is scanning it for me.

Many thanks to Larry for doing the research and sharing a scanned copy of Dr. Richards’ thesis about this Crosley benchmark receiver!

Click here to download A.P. Richards’ thesis as a PDF.

The Crosley Radio Corporation’s 1936 “WLW Model Super-Power Radio Receiver”



(Source: Nuts and Volts)

In 1935, the Zenith Radio Corporation produced a stunning radio receiver called the Stratosphere model 1000Z. The set used 25 tubes and three loudspeakers — more than any other radio to date. An amazing (for the time) 50 watts drove its three speakers — one 6 inch dynamic high-frequency and two 12 inch dynamic low-frequency speakers.

Standing 50-1/2 inches tall, the Stratosphere sold for $750.00 — more than many automobiles; in comparison, a new Ford cost $652.00. At that price, it’s no wonder that only about 350 sets were produced during the four years that the Stratosphere was offered.

This achievement impressed Powel Crosley, Jr. — the President of the Crosley Radio Corporation — who praised it as a fine example of quality in radio construction, but it used “only” 25 tubes and three speakers! Crosley — who also owned the 500,000 watt powerhouse radio station, WLW — was inspired to surpass Zenith by bringing the world the largest and most powerful radio receiver yet known.

[…]Out of the numerous [engineering conferences were held throughout the winter months] and Crosley’s imagination came the basic specifications: the radio would be a superheterodyne receiver with no fewer than 30 tubes, six loudspeakers, four chassis; a suitably impressive cabinet would house it. More intricate than any set ever built, it would naturally have the highest possible quality and richness of tone.

[…]In its completed form, the WLW Model Super-Power Radio Receiver indeed surpassed the Zenith Stratosphere model. It had 37 tubes, six speakers, and 75 watts of power. The cabinet stood 58 inches tall, 42 inches wide, and 22 inches deep. Everything inside the cabinet that could be was chromium-plated. The transformer coils, tubes, and speaker frames were finished in black and each chassis had its own serial number plate.

Continue reading the full article at Nuts and Volts…

Regular SWLing Post readers know that I’m a bit of a vintage radio nut, so I thought I’d do a little digging to see if any WLW Model Super-Power Radio Receivers had been sold or auctioned recently.  I was curious what sort of price they’d fetch.

Let’s just say, some owners demand a high price…Crosley-WLW-Receiver-eBay

This unit was put up for sale on eBay for $160,000 US last year! While I know the Crosley WLW receiver is rare, that price was obviously over the top as is wasn’t sold. Still, the seller included some great photos of this near-mint model:


WLW Model Super-Power Radio Receiver-1 WLW Model Super-Power Radio Receiver-2 WLW Model Super-Power Radio Receiver-3 WLW Model Super-Power Radio Receiver-4

Around the time of the Zenith Stratosphere and the Crosley WLW–the mid to late 30s–radio manufacturers must have either believed there was a market for these high-end, high-fidelity receivers, or they simply enjoyed designing and manufacturing them as a company benchmark or showpiece.

While not as feature-packed as the Crosley WLW receiver, at the National Capital Radio and Television museum last year, I was completely enamored with this gorgeous powerhouse console: the E.H. Scott All-Wave 23 console.


The docent told me that the E.H. Scott All-Wave 23 console could easily fill a banquet hall with hi-fi audio. It sported 23 tubes and a very large speaker. If memory serves, it originally sold for $750–easily three or four times the price of most console radios.Scott-Console-Radio-Dial

Post readers: Do you know of any other benchmark console radios?  Do you own one of these amazing receivers?  Please comment!