Category Archives: Manufacturers

A review of the LnR Precision LD-11 QRP transceiver

The following review was originally published in the October 2016 issue of The Spectrum Monitor magazine.


ld-11-npota-pk01Anyone who knows me knows that since I was licensed nearly twenty years ago, I’ve been a fan of low-power (QRP) operations. There’s just something inexplicably fun in being able to talk to the other side of the world using very low wattage. In a sense, I’ve always felt that, in the world of ham radio, QRP is truly the province of the magician.

It’s for this reason that I’ve owned, operated, reviewed, and beta-tested a number of QRP transceivers over the years. What I look for in a QRP transceiver is quite different than what I’d look for in, say, a base station or mobile transceiver. The glory of QRP gear is that it’s more portable than its “full gallon” cousins in the transceiver world, allowing for radio communications on the go. QRP rigs tend to be more compact, lighter in weight, easier on batteries, less expensive, and provide built-in features to support field operation–even winter glove operation.

Of course, however, there’s typically compromise in smaller packages; neither would I expect a modest QRP transceiver to perform like a full-size base station. But I do expect it to perform well enough to satisfy my needs in the field or the shack.

Introducing the LD-11

lnr-precision-ld-11-am-mode-voice-of-greece

LnR Precision, Inc., is a North Carolina-based company that specializes in antennas, straight-keys, and last but not least, QRP transceivers. The company has produced a number of innovative QRP transceivers over the years, and for many of these years, I’ve been admiring these from afar. But earlier this year when the company announced their latest QRP transceiver, the LD-11, I was especially intrigued.

What really caught my attention this time is that this little transceiver is based on the architecture of their popular LD-5–a five-band, stand-alone direct conversion transceiver. Yet the LD-11 is actually an upgrade on that model, in that it supports 160-10 meter operation with all modes (SSB, CW, CW-R, Digi, AM and FM). Curiosity got the best of me: I had to see this for myself. I contacted LnR Precision, who kindly loaned me a transceiver for review.

Overview

The left side sports the key and mic ports, headphone jack, a line in/out jack and a side tone adjustment.

The left side sports the key and mic ports, headphone jack, a line in/out jack and a side tone adjustment.

The first thing that catches your eye is the unusual color of the LD-11: it is red. Very red. Though opinions will surely vary, I rather dig the hot-rod red aluminum chassis of this little rig. The red faceplate makes the buttons quite visible as well as giving the radio a unique and vivid appearance.

The backlit LCD display, meanwhile, is crisp and easy to read. It’s large enough that all of the pertinent information (frequency, voltage, mode, filter selection, and tuning step) can be displayed at once. When in transmit, there’s a meter below the frequency that displays either a bar scale or numbers for SWR or Power; when in receive mode, it displays the “S” meter.

The LD-11’s buttons have a tactile, responsive, and smooth action. The tuning knob, while lacking a finger dimple, rotates easily with an appropriate amount of brake.

You'll find the DC port, PTT out, CAT port and Antenna input on the right side of the LD-11.

You’ll find the DC port, PTT out, CAT port and Antenna input on the right side of the LD-11.

LD-11 operation is really very simple. I was probably on the air for hours before I ever needed to reference the owner’s manual for functions. LnR has done a great job giving the LD-11 a logical menu layout and intuitive front panel functions.

The radio’s front panel allows you to do the following:

  • turn the radio on/off,
  • tune with the encoder,
  • adjust AF gain,
  • key lock the front panel,
  • toggle the panadapter display,
  • toggle pre-amp and attenuator,
  • change tuning steps,
  • change mode,
  • move between bands,
  • turn on noise blanker and noise reduction
  • operate RIT and set-up split,
  • toggle VFOs, and
  • enter menu functions.

The menu functions give you control of still more settings, such as AGC settings, CW configuration, mic/voice transmit configuration, notch filter settings, NB/NR settings, meter display, transmit power, backlight settings, squelch, digital gain, and AM/FM mode enable/disable, among others. So this little transceiver is feature-rich.

Moreover, most menu items can be changed while you’re transmitting. While on the air, for example, I regularly toggle the transmit meter display between power out and SWR while calling CQ. Very handy.

Again, operation is straightforward and simple, especially good because at time of publishing this review, the LD-11 owner’s manual is still quite basic (click here to download PDF version).

On the air

Unlike most of my review radios, which spend a great deal of time in the shack during the evaluation period, the LD-11 spent most of its time in the field–in several US states, as well as in a couple of Canadian provinces. I even used the LD-11 for two weeks in an off-grid cabin on Prince Edward Island, Canada.

The LD-11, QRP Ranger, and Z-11 auto-tuner at the Hopewell Culture Park NPOTA activation.

The LD-11, QRP Ranger, and Z-11 auto-tuner at the Hopewell Culture Park NPOTA activation.

My first outing with the LD-11 was at Hopewell Culture National Historical Park in Ohio. Buddy Eric (WD8RIF), his son Miles (KD8KNC), and I made four National Parks On The Air (NPOTA) activations en route to the 2016 Dayton Hamvention.

We had a tight schedule for our NPOTA activations, so I couldn’t spend a great deal of time setting up my equipment. So on that day, I paired the LD-11 with Eric’s Z-11 auto tuner and a homebrew 40-meter doublet suspended from a tree. I powered the LD-11 with my Hardened Power Systems QRP Ranger battery pack.

And this combo worked brilliantly. At Hopewell, for example, I made twelve contacts, in short order, running SSB with just 8-10 watts output, and received positive audio reports.

Also that day, I discovered how exceptionally easy it is to operate the LD-11 in the field. When packing in, I appreciated how lightweight and compact it is, and that fire-engine red chassis meant there was no way I’d overlook it or forget it on the ground.

The LD-11 has two fold-down feet to support it on the shack table or in the field.

The LD-11 has two fold-down feet to support it on the shack table or in the field.

Two missing features, however, might make the LD-11 even more portable: these are an internal battery pack and an internal ATU. Unfortunately, there are no options for these at present (LnR, take note).

The LD-11 feet fold neatly under the chassis.

The LD-11 feet fold neatly under the chassis.

The external ATU, meanwhile, adds several extra items to manage: the ATU unit, the power cord, and an extra patch cable. Sure, if you’re operating all day from one location, none of that really matters. But when you’re doing quick deployments, every bit of kit that doesn’t require packing and unpacking also saves time and potential frustration. But I cheerfully used the above combo the rest of the day, logging even more contacts.

The EFT Trail-Friendly Antenna

At the Dayton Hamvention, I decided that one way to avoid taking an ATU to the field was to use a multi-band resonant portable antenna. I was quite busy at the Hamvention and didn’t want to spend time building one, so I decided to take the quick route and simply buy one. I visited a few vendors in Hara Arena and was impressed with the selection of field-portable antennas available. In the end, I was taken by the compact and easy-to-deploy design of LnR Precision’s EFT Trail-Friendly antenna, and purchased one on the spot. As many potential LD-11 owners might purchase the same antenna, I decided it might help to review it, too.

The EFT Trail-Friendly antenna is incredibly compact and quite easy to deploy.

The EFT Trail-Friendly antenna is incredibly compact and quite easy to deploy.

I bought a version of the EFT antenna that is resonant on 40, 20, and 10 meters. I like that band combo for NPOTA and SOTA activations, because I like operating on both the 40 and 20 meter bands. What’s especially brilliant about the EFT end-fed design is that you only need to suspend one side of the antenna: simply launch a line over a tree branch, and hoist the business end of the antenna up, and, snap–you’re ready to go. When wound up for transport, it’s also lightweight and takes up very little space in a kit bag.

On the way home from the Hamvention, we activated the same four parks yet again. Eric and I tuned the EFT antenna before its initial use, and it was then ready to go.

Eliminating the need for an external tuner and adding the simple EFT antenna to the mix meant that I could set up and take down my entire station in a matter of minutes.

The only thing that took time at all was finding a tree branch to hoist the end of the antenna–usually not a problem, especially in our Eastern US parks. Moreover, the transceiver-plus-antenna team was quite effective: I easily logged all the contacts needed for all four sites in the one-hour time slots we allotted.

LD-11 Performance

The QRP Ranger (left) and LNR Precision LD-11 transceiver (right)

The QRP Ranger (left) and LNR Precision LD-11 transceiver (right)

In brief, I’ve been very pleased with the LD-11’s performance on the air.

The LD-11 receiver is both sensitive and selective. Though I didn’t have the chance to test it in the RF-dense environment of Field Day, it never overloaded in the areas where I’ve operated.

Through my headphones, the LD-11’s noise floor is impressively low and the receive audio is excellent. At first, I was a bit disappointed that the LD-11 doesn’t have an RF Gain control–something I frequently use to mitigate background noise–but fortunately the noise floor is low enough, and the DSP architecture seems adaptive enough, that I’ve never needed to reach for an RF gain control so far.

Nonetheless, LnR: I do hope you’ll consider making RF Gain a future firmware update!

Modes

The LD-11 is jam-packed with modes: USB, LSB, CW, CW-R, AM, and FM.

The LD-11 can also handle a host of digital modes, and there’s the choice of two models to connect to your PC: one LD-11 model with the Prolific USB Adapter Chipset ($739), and another model with the more-universal FTDI chipset ($789). It’s outside the scope of this review to test the LD-11 on digital modes, but note that I plan to do so in the coming months. The modes I’ve tested thus far are SSB, CW, and AM.

When I operated SSB, I found the default filters quite effective and the receive audio pleasant. On transmit, I received a number of positive reports on the LD-11’s audio. What’s more, through a menu option you can can adjust the transmit audio equalization (three defaults) to better match your voice.

On CW, the LD-11 was equally as pleasant. On-board filtering is quite effective and audio well-balanced.

On transmit, there is one negative worth noting for the CW operator: the LD-11 does not have full break-in QSK.

While this isn’t a problem for me, because I find hearing signals between the dits and dahs I send rather distracting, I know many CW ops that don’t like using a delay on transmit, preferring instead a full break-in. LnR notes that the LD-11’s “maximum switching delay is 12mS and digital delay is 47mS.” If you set the LD-11 for the quickest response time, you can hear between most characters, but the relay clicking can be distracting. For all of my CW operations, I set the response time to 500ms.

The first time the LD-11 was operated in CW it was with my buddy Mike Hansgen (K8RAT). Later, I asked this experienced operator how the LD-11 sounded on the other end? His reply:

“The LD-11 put out a sweet, musical note that was very pleasant and reminiscent of the note of a valve transmitter. The LD-11 sounded better than any silicon transceiver I had heard in a long time.”

Wow…high praise, indeed. For those who don’t know him, Hansgen has high standards, and doesn’t hand out such compliments readily.

AM mode (and general coverage)

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

LNR-LD-11-Shortwave-AM

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

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

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 prefer the former method.

Since the LD-11 has a proper AM mode, broadcasts sound great–especially via headphones! Better yet, the AM filter width can be widened to an impressive 9.6 kHz–! When listening to a blowtorch signal, audio fidelity is most impressive.

For example, here’s an audio sample of the LD-11 tuned to the Voice of Greece on 9420 kHz, with a filter width of 9.6 kHz:

Click here to listen to a comparison of the LD-11 and Elecraft KX2 on the 31 meter band.

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).

The F4 position 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, again simultaneously, will save your filter width for the F4 position.

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

A panadapter

One final unique feature of the LD-11 is a built-in, simple panadapter. By pressing the F (function) and VFO buttons simultaneously, it will engage the panadapter which lines the bottom of the display.

The panadapter display is found at the bottom of the LD-11's backlit display.

The panadapter display is found at the bottom of the LD-11’s backlit display.

To be clear, the panadapter is very basic–it doesn’t include frequency markers, it’s monochrome, and it’s not very tall (height/depth helps to discern weak signals along the spectrum). In fact, when I first turned it on, I truly doubted its utility.

Yet after having used the LD-11 for several months, I can say that one of the first steps I now take when putting the rig on the air is to engage the panadapter. Though it’s quite simple, I find it a useful tool for chasing signals on bands, whether SSB, CW, or even AM broadcasters. It’s also very responsive and fluid, which helps make up for the fact that it’s solid in color and rather flat.

For example, the weekend before finishing this review, I activated PK01 (the Blue Ridge Parkway) for NPOTA. When I switched to 20 meters, the noise floor was so low that, when I first started calling CQ, I assumed that either the band was dead or the antenna wasn’t working. One look at the panadapter, however, showed me that there were some strong SSB signals on either side of my frequency. So I didn’t tune around, but simply continued to call CQ, which soon rewarded me with excellent catches (more on that below).

Summary

Invariably, all radios have strengths and weaknesses; here is a list of these from the moment I put the LD-11 on the air:

Pros:

  • Lightweight, compact size
  • Excellent ergonomics and simple menu-driven functions
  • Built-in, simple panadapter
  • Low current drain on receiver (….ma)
  • General coverage receiver
  • Low noise floor
  • Variable filter bandwidths
  • Rugged hand mic
  • Most menu items can be changed while operating PTT or CW
  • Headphone amplifier drives larger headsets
  • Internal speaker (see con)
  • Excellent CW transmit audio reports
  • Good LnR Precision customer service

Cons:

  • No internal ATU option
  • No internal battery option
  • No RF gain control (see noise floor pro)
  • CW operation is not full break-in QSK, some relay noise
  • No voice or CW memory keyers
  • Very basic owner’s manual
  • Occasional audio “pops” when tuning rapidly through a band
  • Internal speaker audio is mediocre (see pro)

ld-11-qrp-ranger-npota-pk01

All in all, the LD-11 is a superb little transceiver. It sits in a market with some heavy-hitters like the venerable Yaesu FT-817ND, the Elecraft KX3, and the new Elecraft KX2 (which I reviewed in the November 2016 issue of The Spectrum Monitor Magazine).

While the LD-11 lacks some of the portability of those rigs (specifically, options for an internal battery and ATU–again, please take note, LnR), its performance-for-price-point is right, in my opinion.

If you take the LD-11 to the field with a resonant antenna, as I have, all you need is a power source to be on the air in moments. If you pair the LD-11 with a simple ATU like the Emtech ZM-2 or the even smaller Elecraft T1, you’ll be able to tune wires to your heart’s content, and you won’t need extra power cables.

Oh, yes…there’s one more thing I must mention about the LD-11: this rig has, for lack of a better word, a “fun” factor. It reminds me of one of my favorite QRP radios from days gone by, the Index Labs QRP Plus. The QRP Plus had many performance shortcomings and wasn’t nearly as full-featured, as lightweight, or as small as the LD-11, but it was a fun radio due to its dead-simple controls, nice display, prominent tuning knob, and good ergonomics generally, making it a breeze to operate.

The LD-11 feels like what the QRP Plus should have been: a fun rig that delivers serious performance.

The LD-11 is also easy to use, and that certainly contributes to its sense of fun. Operation has clearly been well thought through by the LnR developers. Only a few days before capping off this review, I took the LD-11 to the field for its 6th National Parks On The Air activation. With eight watts in SSB and a 20 meter vertical, I worked Rhode Island, Texas, Montana, Manitoba, California, and Slovenia from a picnic table on the Blue Ridge Parkway. And it was great fun, underscoring the reason I get such a kick out of HF and QRP in the first place.

Of course, that’s the magic and the mystery of radio. But tools like the LD-11 make it all the more accessible. LnR Precision, I must say: pretty good trick. From your proverbial hat, you’ve produced the handiest little QRP rig I’ve seen in years.

Click here to view the LD-11 on the LnR Precision website.

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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.

KWZ-30

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.

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

LNR-Precision-LD-11

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-7300 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!

LNR-LD-11-Shortwave-AM

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. 

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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.

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

Crosley

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.

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

Crosley

(Image: AntiqueRadios.com)

(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:

Crosley-WLW-RX

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.

Scott-ConsoleRadio

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!

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The KRC-2 shortwave regenerative receiver kit

KRC-2 shortwave regenerative receiver kit1

Tony Westbrook recently contacted me about a regenerative receiver kit he has designed and produced in the UK.  It’s called the KRC-2.  Here’s the product description:

1 – 30 MHz with band spread tuning.

Regeneration with a difference. The regeneration setting on the KRC-2 is unaffected by the receiver tuning or the antenna coupling. How do we achieve this? The regenerative stage is fixed at 10.7MHz and used as an IF amplifier. The main receiver board is extremely simple to construct using only one FET and an audio IC. Like all the KRC kits it comes with a comprehensive construction manual which brings this project well within the grasp of the keen constructor. It was referred to as “a very sensitive little receiver” by Rob Mannion of Practical Wireless. Its unconventional design and simplicity should amaze even the experienced constructor. Case size 7 x 4 x 3 inches. 6 x AA batteries supplied.

According to Tony, the kit comes with everything; UK orders are even supplied with batteries. Tony stated, “the only thing the customer needs is a soldering iron, solder cutters, etc.”

By request, Tony sent a few construction photos and three videos of the radio in operation:

Photos

KRC-2 shortwave regenerative receiver kit4KRC-2 shortwave regenerative receiver kit11 KRC-2 shortwave regenerative receiver kit10 KRC-2 shortwave regenerative receiver kit8 KRC-2 shortwave regenerative receiver kit7 KRC-2 shortwave regenerative receiver kit3 KRC-2 shortwave regenerative receiver kit2 KRC-2 shortwave regenerative receiver kit9 KRC-2 shortwave regenerative receiver kit6 KRC-2 shortwave regenerative receiver kit5

Videos

Video 1

Video 2

Video 3

Click here to view the KRC-2 and Tony’s other kits. 

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