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Many thanks to SWLing Post contributor, Ivan Cholakov (NO2CW), who writes:
My 11 year old son Tommy (N1SPY) completed a project where he compared a 1W lightbulb to a .25 W radio beacon that he put together and bet that the radio beacon can be heard around the world. I asked him to document his activities as he went along. The project took a couple of months but is now complete and we stitched together a video of his activities.
I especially like how you’ve taken time to explain the principles behind the various steps of the process. Brilliant job!
Tommy, your future videos are always welcome here. Keep up the good work and we’d love to hear how many new countries you’ve racked up on your WSPR system!
Many thanks to SWLing Post contributor, Pete (WB9FLW), who notes that Ashhar Farhan (VU2ESE) has upgraded the BITX40 Transceiver with a Arduino Nano/Si5351 VFO:
My buddy, Skip Arey (N2EI), shared the following poem on his Facebook page and has kindly allowed me to post it here!
Skip writes:
“I originally published this in the NASWA “FRENDX” club journal in 1987 and later in the December 1992 issue of Monitoring Times magazine. Many thanks to Steven K. Roberts for recovering the text for me as it never stuck to my hard drive. Enjoy.”
A DXer’s Christmas
(With apologies to Clement Clarke Moore)
‘Twas the night before Christmas, and all through the house The “Harmonics” were sleeping, and so was the spouse; The antennas were hung from the chimney with care in hopes that some signals would come through the air; The receivers were nestled all neat in a row, With filters and tuners all ready to go; With a strong cup of coffee, sitting at my right hand, I had just settled in to some radio band, When out of my headphones there arose such a clatter, I sprang from my desk to see what was the matter. Away to the window I flew like a flash, To determine the cause of this odd static crash. The Moon on the breast of the new -fallen snow, Gave my antenna wires an unusual glow; When what to my wondering eyes should appear, But a weird little sleigh and eight tiny reindeer. With a strange little driver, who looked like a “Hippie,” I though for a moment my brain had gone dippy. More rapid than eagles his coursers they came, And he wheezed, and he cursed, as he called them by name: “Now Ten-Tec! Now Icom! Now Yaesu and Philips! On Grundig! On Sony! On Kenwood and Collins! Watch out for the porch! Watch out for the wall! Stay out of the way, and don’t let me fall!” As dry leaves that before the wild hurricane ride, When they met with an obstacle, they kicked it aside. So up to the house -top the coursers they flew, And got tangled in wire; the old Hippie did too. And then, in a twinkling I heard through the ceiling, a great deal of cursing, and swearing, and squealing. As I shook my head, and hollered out “Stop!” Down the chimney the bearded one fell with a plop. He was dressed all in denim, from his headphones to tail, His clothes smelled like sweatsocks, and his breath like cheap ale; The stump of a stogie he held tight in his teeth. And the rancid smoke circled his head like a wreath; He had a fat face and a great big beer -belly, That shook when he burped, like a bowlful of jelly. He spoke not a word but went straight to his work, Opened up my receiver, and tuned with a jerk. Then sticking a finger inside of his nose, And giving a burp, up the chimney he rose. The receiver it squealed, and gave out a whistle, And the stations I heard that night, would fill an epistle. And I heard him exclaim, ere he drove out of sight, “Happy DX, Old Man, next time, leave on a light!”
Anyone 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, 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 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.
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.
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.
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 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.
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)
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.
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.
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.
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
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.
Blue Ridge Parkway and Great Smoky Mountains Park (PK01 & NP26)
Appalachian Trail and Great Smoky Mountains Park (NP26 & TR01)
I’ll only get credit for three activations, but chasers will have a better opportunity to snag two park entities in one QSO.
I plan to activate the PK01 & NP26 two-fer starting around 17:00 UTC, then the NP26 & TR01 two-fer starting around 19:15 UTC. Look for me on 14,286 and 7,286 +/- 6 kHz.
SWLs: please comment if you happen to hear me at your location!
On the way back from the conference, Sunday morning, I plan to activate the same sites once again (weather permitting).
I should go on the air sometime between 16:00-17:00 UTC (12:00-13:00 EDT), weather permitting.
I’ll plan to start on the 20 meter band (14286 kHz) then move to the 40 meter band (7286 kHz). If I can’t operate on those frequencies, I’ll move to something clear +/- 6 kHz or so.
Side note: yesterday, I picked up an REI Trail Stool to replace my foldable camping chair.
The camping chair is fantastic if you don’t have to lug it very far, but on long hikes it becomes heavy and cumbersome. This stool will get me off the ground and hopefully allow me to operate with the clipboard and transceiver on my lap. The REI Trail Stool weighs next to nothing.
If you’re an SWL and hear me (K4SWL) on the air, please comment! Note that I’ll be transmitting a max of 10 watts–so pretty much “flea power.” Still, in the past, I’ve worked all corners of North America and into Europe with this same transceiver/antenna combo.
Propagation conditions are pretty favorable today as well. I just hope we have no pop-up thunderstorms–I’ll most likely be near a ridge line and can’t take any chances.
If you’re a ham radio operator, I hope to log you for this activation!
My new Elecraft KX2 tuned to Radio Australia this morning.
I’ve only had my Elecraft KX2 since Monday evening and have been so busy, I’ve only had an hour or so to tinker with this pocket transceiver. Monday evening, before putting it on the air, I updated the KX2 firmware to the latest Beta release which includes the new AM mode.
I’ve had so many questions from readers about the KX2’s AM audio already, I thought I’d do a quick comparison with the LNR Precision LD-11.
I set the LD-11 to a bandwidth of 9.6 kHz, and the KX2 to 5 kHz: their widest AM filter settings. Keep in mind, this is not an apples-to-apples comparison, but it does showcase each radio’s potential AM audio fidelity.
I tuned both rigs to the Voice of Greece last night on 9420 kHz around 00:30 UTC. VOG’s signal was strong into North America.
I made the following recordings with my Zoom H2N digital recorder, by feeding in-line audio patched from each radio’s headphone jack. I tried to balance the audio levels between the two rigs.
Note: Some Elecraft radios have an audio effects mode which includes a “delay” function. Elecraft describes it as “a quasi-stereo effect intended to provide depth and space to the received audio.” On an AM broadcast signal, it makes it sound wider and gives it almost a stereo depth.
I think the results from both radios are impressive. Since the LD-11’s bandwidth can be widened to 9.6 kHz, strong signals like this one sound pretty amazing. In truth, I actually prefer a filter width of about 8.2 kHz on strong signals, but VOG was wide enough to justify 9.6 kHz. I believe the LD-11 would rival many dedicated tabletop receivers.
The Elecraft KX2, in normal audio mode, sounds flatter and narrower than the LD-11 of course, but still very pleasant! In the KX2’s “delay” audio mode, the signal sounds much wider than 5 kHz, though the effect adds a little graininess to the audio. That’s okay, though–I love having the “delay” audio option in my tool bag.
Here’s what amazes me as an SWL and ham radio operator: both of these QRP transceivers offer excellent HF broadcast listening opportunities.
Please comment! Which audio sample do you prefer? Do you like the “delay” audio effect on the KX2? Keep in mind this is only one comparison and doesn’t address sensitivity or selectivity.
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Anyone 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.
This also affords me the opportunity to activate two “two-fers” for the 
