LD-5 HF Ham Radio QRP Transceiver

The LD-5, made in USA, by LNR Precision Inc. is an amazing little 5 band SSB/CW Amateur Radio QRP Transceiver that’s small and light enough to fit in just about any backpack. this makes it one of the most portable SSB multi-band HF rigs currently on the market. Not only is the LD-5 small in size at 4.724”L X 3.937”W x 1.957“H, it is also very lightweight, weighing in at only 1.19 pounds (without microphone, antenna, or battery).

The LD-5 covers the following HF ham radio bands: 40m, 30m, 20m, 17m, & 15m. One of the features of the LD-5 I have really enjoyed is how each of the 5 bands has its own independent dual VFO. This really comes in handy when switching back and forth between bands/frequencies and really sped up operations for me compared to other QRP rigs I have used. I found the receiver to be exceptionally sensitive and able to pick up the weakest of signals.

There are a few features that you typically wouldn’t find on most QRP HF rigs that the LD-5 has, such as CW/SSB VOX, noise blanker, notch filter, noise reduction, PRF/ATT (Pre Amp/Attenuator) and even speech compression. Based on my testing, I found all of these features extremely effective at improving my ability to hear and be heard by other hams. I am convinced that several of of the contacts I made would have been impossible if I didn’t utilize the various filtering, noise reduction, and speech compression capabilities that are built into this amazing little radio. As far as I know, the LD-5 is the only 5 band QRP SSB HF ham radio with all these features that is sold new for under $600.

The LD-5 is capable of much more than just SSB and CW. It is also capable of various digital modes such as PSK, RTTY, SSTV, and even HF APRS when used with the proper TNC/modem and computer with sound card. The menu system contains nearly two dozen settings that allow you to custom tailor the LD-5 to suite your specific needs and preferences. Luckily, there are also 13 buttons and 2 knobs on the LD-5 that allow you to manipulate many features without diving into the menu system. The tuning knob also has a really good sturdy feel and smooth movement while tuning. I especially enjoyed the bright and high contrast display with its power saving auto off feature for the backlight.

You might not realize it when looking at it but the LD-5 is actually an SDR (Software Defined Radio) with a software platform that was created exclusively for the LD-5. It uses only one Kenwood driver for CAT system fast connectivity. In the slideshow of this article, I have include a diagram that LNR shared with me which illustrates how this system works. When I asked LNR for more details on this being an SDR, they quickly gave me the following very detailed response:

“It combines a powerful low internal noise schematic of a DSP and a special differential algorithm is applied for IQ processing of the channels with phase suppression of the unwanted side-band channel. Balancing ADC and DAC gives additional noise floor reduction and the receiver can handle interfering signals that are 100 dB stronger than the desired signal at a frequency separation of 10 kHz, and is about 130 dB stronger at 50 kHz separation. As the receiver and transmitter are using the same DSP channel, there is no gap between the receiver performance and the transmitter performance. So, there is a clean neighborhood on the bands. At the development stage, our intentions were motivated by the TX sideband noise of existing SDR manufacturers, so our aim was, to fully equalize our transmitter to have noise performance that is compatible with the best modern receivers, or even better. After a arduous year of development , we think we achieved it.”

A nice assortment of input and output ports allow you to widely customize the way you use the LD-5. These include jacks for: line in/out, phone out (headphones/speaker), mic in, key (CW straight key or iambic paddles), PTT out, BNC antenna connector, 12 volt DC power input, and even a USB/CAT port. The built-in USB port is another stand out feature on the LD-5. Not only will the USB port allow you to update the radios firmware, it will also allow you to interface the LD-5 radio with your computer, which allows you to use Mac/PC ham radio software programs such as N1MM, MiXW, Fldigi, and more.

During my field testing of the LD-5, I brought it along on a road trip up and down the California, Oregon, & Washington coastline. When stopped long enough, I would set up the EFT-MTR 40m/30m/20m 65’ QRP End Fed antenna made by LNR. On one occasion, I was fortunate enough to stay on the second floor of a bed and breakfast situated on a hill. This allowed me to drape the 65’ EFT-MTR End Fed antenna out the window and down the roofline in somewhat of a sloper configuration, which worked quite well with the LD-5.

During shorter stops at various beaches and state parks along the coast, I set up the LD-5 with my “Wonder Wand” and “Miracle Whip” antennas, which sets up in seconds, packs up small enough for most backpacks, and doesn’t require any masts, ropes, tripods, clamps or long wire. Both are all band 52” vertical telescopic whip antennas with a built-in dial for tuning to each band. These antennas work fairly good with the LD-5 and I have been able to make contact with hams that were within a couple hundred miles away while using them.

During another trip, I used the same 65’ End Fed EFT-MTR from LNR in a sloper configuration with a 22’ collapsible fiberglass mast while camping on a beach near Santa Cruz, CA. With that particular setup, I made SSB contacts on 20m & 40m at 573 miles into Oregon, 676 miles into Washington State, 202 miles into Nevada, 657 miles into Idaho, and 860 miles into Montana. With each of these contacts, I was only using 4 Watts of RF power output.

A couple of my longer distance SSB contacts using the LD-5 included several different contacts that were 1,352 miles away in Kansas on 20 meters while using only 5 watts. My longest distance contact with the LD-5 so far was a 2,349 mile contact on the 15 meter band made to New York, again with only 5 watts of output power. The antenna I utilized to make these contacts is my Carolina Windom 40 off center fed dipole, which is up around 30 something feet off the ground in an inverted V configuration.

The LD-5 is known for being able to make much long range contacts than I have made with it so far. For example, my contact at LNR Precision Inc. informed me that while conducting a demo of the LD-5 at the Huntsville, AL Hamfest this year, a customer made contact with a fellow ham operator located on Rodrigues Island in the Indian Ocean while using a simple 20 meter end fed antenna oriented vertically which is made by LNR. Thats an impressive 10,330 miles! Not too shabby for a 5 watt radio the can fit inside a kid’s lunch box.

As far as the performance of the included microphone is concerned, I think it works great. It produces clean and clear audio without any noticeable over modulation, even when talking quite loud into it. A small speaker is built into the right side panel of the radio. The speaker produces decently clean audio but is a little on the weak side when it comes to audio volume output, especially when there are background noises such as road noise, wind, or waves breaking on a nearby beach. If you are in a nice quiet spot, the speaker works great, but if there is any background noise, I recommend using headphones or an external amplified speaker.

Even though the included mic works great, in my opinion, it’s not the best fit for this radio. Considering this radio is designed to be compact for portable use such as backpacking, I find it odd to include a microphone that takes up nearly the same amount of space as the radio itself when packed. Luckily, the included mic can be unplugged and replaced with whatever kind of mic you prefer to use. I plan on modifying a MFJ-285 mini HT speaker microphone to work with the LD-5. These little inexpensive HT mic’s are roughly 1/4 the size of the included mic and might be better suited for QRP backpackers with limited room in their packs.

A power plug and cable with bare ends is also included for you to connect to the battery or power supply of your choice. The LD-5 is designed to be powered from 10.5 volts to 15 volts DC. I happened to have 2 fairly compact 12 volt batteries on hand. One is a SLA (Sealed Lead Acid), the other is a LiPo (Lithium Polymer). The LD-5 worked flawlessly with both types of batteries. If you plan on carrying this radio around in a backpack, I highly recommend going with a small 12v lithium battery since they weigh around 1/3 the weight when compared to an SLA battery of comparable power capacity. You might also want to consider a small lightweight folding solar panel so you can keep your battery topped off when operating from the great outdoors.

I was fortunate enough to have a spare small waterproof foam padded hard case that is not much bigger then the LD-5. There was just enough room in the case to also cram in a lithium battery, power cable, mini straight key, headphones, counterpoise, small logbook, mini pencil, and a printout of the ARRL band plan for good measure. This allowed me to pack the LD-5 into a backpack and hit the trail without worrying about it getting banged up against my other gear. Protective cases such as this are in my opinion a necessity and can be easily found in a wide variety of local and online stores.

One of the really nice finishing touches on the LD-5 isn’t high tech at all. It’s the little fold out legs that allow you to conveniently prop up the radio at a much more comfortable viewing angle. So many QRP radios and kits out there just don’t come with a stand/foot and it can really impede your ability to use the radio. To me, this simple feature is the icing on the cake for this radio, making it a real pleasure to use.

I have used several different portable HF QRP rigs now and even built a few myself. Out of all of them, the LD-5 from LNR is by far my favorite. I found its ability to filter noise and pick out those weak signals very impressive. It has tons of great features, quick to setup, easy to operate, reliable, and just plain fun. Its compact size and lightweight construction make it an ideal radio for portable operations such as camping or backpacking. I can tell that LNR takes great pride in their work based on the build quality of their products as well as their staffs willingness to happily help you out with any questions or problems you might possibly encounter. I highly recommend this radio for anyone who is interested in operating portable QRP in the great outdoors without breaking the bank.

73! from James Hannibal – KH2SR

Made in USA

Price: $575

For more info, please visit the following links:

LD-5: https://www.lnrprecision.com/store/LD-5-p39885476

EFT-MTR 40m/30m/20m End Fed Antenna: https://www.lnrprecision.com/store/EFT-MTR-p52039905

If you don’t have a ham license and want to learn more then check out these links:

What Is Ham Radio: http://www.arrl.org/what-is-ham-radio/

Getting A Ham Radio License: http://www.arrl.org/getting-licensed



Input Power: 10.5-13.8 VDC

Output Power: 3.5 – 8W

Measurement: SWR and Power:Numbers or Bar indicators on display

Supply Voltage: Real voltage on display

Two Modes CW: Select Straight Key or Paddle


Receive sensitivity: 0.2uV Preamp

Ant Preamp: +12 dB

Spurious Response Rejection: IMD3 -48Db/ 5W

IMD5 -43dB

ATT: -6db

Frequency Range: 7000 kHz – 22 MHz 40, 30, 20, 17 and 15 meter operation Modes: USB, LSB, CW, CW-R, DIGITAL DATA:CAT –USB jack : CW, PSK, RTTY, SSTV – 3.5mm input/output audio jacks

Power: 3.5 – 8W output in CW / SSB

Frequency Stability: +/- 3 ppm (Si570 defined) typical over 0-50 deg C

Supply Voltage: 10.5V min to 15V max 350mA receive and 1.5 to 2A typical in transmit

LO temp. Stability: +/- 2.5

Antenna: 50 ohms BNC

Dual VFO

Memory: 100 memory storage per band Memorize frequency, mode, VFO’s Built-in speaker: 0.2 watts

Dimensions: 4.724”L X 3.937”W x 1.957“H

Weight: 19oz/0.54k excl. mic.

Iambic key: Mode A and Mode B

Pitch CW: Controls CW offset. Sidetone pitch is automatically set to equal the offset

Notch Filter: Automatic Heterodyne filter for SSB from -6 to -40 db

Noise reduction: Level of attenuation of the noise from 1 to 50- use minimal necessary

Noise Blanker: Adjustable range from value 4 to 12 readings depending on interference

CW VOX: Break in delay in CW – adjustable from 0.1 seconds to 5 seconds CW memory keyer

VOICE VOX: VOX Delay adjustable from 0.1 seconds to 5 seconds SSB VOX Level: VOX GAIN 10-100 10 IS MOST SENSITIVE

8 Different filters (incl): 4 of 4 for CW/ SSB – 1-3 factory presets – No.4 adjustable for CW/50-1000Hz/ and SSB/250-3.6KHz

Compressor: SSB: 0-20dB

SSB TX MUTE: Enable= no monitor Disable= monitor

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