First Impressions of the LD-5

The LD-5 from LNR Precision

OK, so I have had the LD-5 from LNR Precision for about a week and a half now, and I am ready to post some initial thoughts abut it. First of all, some background information. The LD-5 is a 5 band QRP transceiver. It is capable of operating CW, SSB, and digital modes. The bands it works  are 40m, 30m, 20m, 17m and 15m. It takes a standard 13.8 V input, and output power is advertised as 3.5 to 8 V. More on this in a moment. You can read all the specs here, if you’re interested in the fine print.

TL;DR: The LD-5 is an impressive, capable little QRP rig. It’s not the easiest to get connected to a computer for CAT or digital operation, but it can be done. Overall, I’m very happy with it.

Ordering and Delivery

The ordering process was straight forward — web-based store, reasonable shipping fee of 8 bucks or so. Shipping was fast, and tracking information was provided. The unit was packed well, and everything arrived in good order and on time. On opening the box, I found the transceiver, and a box containing cables and mic. This included a USB cable for connecting the radio to a computer, an audio interface cable for digital modes, and a power lead. the power lead has a barrel connector that plugs into the radio, and no connectors at the source end. It’s up to you what sort of connectors you want. I soldered some Anderson PowerPole connectors to mine. The power lead has a fuse pre-installed as well.

Basic Operation

The radio has a BNC connector, and fortunately I had a BNC-PL259 adapter handy, and was able to connect my dipole system to the LD-5. I connected the PowerPoles to my power supply. After powering the radio on, the 16×2 LCD display gives basic information about the setup. VFO A or B, frequency, and mode are shown on the top line, S-meter, and filter setting are shown on the bottom; indicators for the noise blanker, noise reduction, preamp, and attentuator are shown in the bottom line as well, if these features are active.

Most of the adjustments used during normal operation are accessed via buttons on the front panel. Changing modes, bands, and filter settings have dedicated buttons. Another button cycles through the pre-amp, attenuator, or neither. Some buttons have second features, which are accessed by pressing the “F” key first, and then the feature’s button. All in all, the buttons are pretty intuative, and provide a lot of functionality without delving into the menu system.

Speaking of the menu system, there are plenty of options to tweak. VOX settings for both CW and SSB, transmit power levels, CW side tone pitch, keyer speed, and key type are all accessed in the menus, as well as AGC speed. The display can be set to show either SWR or power output during transmit, and the values of either can be displayed as numbers or a bar graph.

The tuning knob is smooth and the step size can be changed with the step button. there are four step sizes available, from 10 Hz to 10 kHz in SSB, and 5 Hz to 1 kHz in CW and digital. Since the display only shows down to the 10 Hz decimal point, the lowest 5 Hz step size means that the lowest decimal point just takes a bigger turn to change than the next step size up. the tuning knob could stand to be a little bigger, or maybe to have a finger dimple on the face. It’s not a big issue, though, more of a preference based on what I am used to with my Yaesu F450D. In any case, selecting bands, modes and frequencies is straight-forward. Jacks for the mic and CW key are plainly labeled, and I was on the air in short order.

There is a small speaker on the right side of the transceiver, and while it is adequate for working in a quiet indoor setting, I imagine portable, outdoor operation might leave it wanting. In fact, in my basement shack, I often have to turn it up to full volume when the furnace or water heater fire up. With a halfway decent headset, the audio levels are more than enough, however, and I don’t anticipate any having any problems with the audio output.

I’ve been fairly impressed with the receiver in this little unit. It is quite sensitive, and if you have trouble hearing a signal, you can kick on the preamp for a 12 dB boost. The four filters become progressively tighter, with the fourth being user adjustable. The filters are quite effective, too. I haven’t done any quantitative evaluation, but on several occasions, I’ve had interference from a nearby signal in CW mode, and by the time I’d stepped up to the third level of filtering, the unwanted signal was suitably rejected.

The sidetone on CW is a little “softer” than I am used to — the keyer on the FT450D is quite crisp, almost to the point of generating key clicks. The softer edges on the LD-5’s keyer makes keying feel a little fuzzy. Again, this is not a big problem, just something for me to get used to. On sideband, my contacts give me good audio reports. The radio has an adjustable equalizer and compression settings to suit your own preferences and voice. The PTT button on the included mic is a little stiff and “clicky” which may lead me to replace it. It has an RJ-45 connector between the mic and cable, so fitting it with a smoother feeling mic should be simple.

CAT Control and Digital Operation

LD-5 in operation
LD-5 in operation

OK, this is where things get a little sticky. I spent a couple of frustrating days trying to get the radio and computer talking to each other. My Raspberry Pi 3 is running CQRLog and fldigi. I read in the forums on the LNR Precision website that the Kenwood TS-2000 profile does a good job with as a hamlib profile. The LNR website also provides settings for serial speed, and other details. Unfortunately, I have not been able to get CQRLog to communicate with the LD-5 at all on either the Raspberry pi or a laptop running Xubuntu. I was able to get flrig to communicate with the LD-5 on both Linux systems, but by itself, this is pretty useless.

Configuring CAT control on a Windows 10 laptop was much simpler. I installed both N1MM+ contest logger and N3FJP contact logger on the laptop, entered the appropriate settings, and had CAT control with little fuss. In addition, flrig also connected pretty simply.

The next level of frustration came with getting fldigi working. The hamlib and rigCAT options sort of work, but the connection doesn’t seem quite complete. Using flrig with fldigi gives solid CAT control, but PTT wouldn’t fire on transmit. I discovered completely by accident that if I unchecked all CAT control options in fldigi’s configuration, and had flrig running, then all seems to work as it should. Very strange. There’s also an XML tab in flrig’s configuration that has a check box about using fldigi as a server, along with IP address and port numbers for fldigi, which I have set on the Windows version of flrig. I’ll try to post more details about getting fldigi working on the LD-5 in a later post.

In any case, I’ve got digital modes working with the LD-5 on Windows. It also works on my Xubuntu laptop, now that I cracked the code, but still no connection to CQRLog. So for now, I’ll use Windows with the LD-5. I’ve had PSK QSOs from St. Louis to Vermont to Arizona and several stops in between, and the guys at the other end say the signal is very clean and readable.

A Note About Output Power

I have noticed a few times when working CW or digital, the displayed output power exceeds the advertised maximum of 8 watts. Getting almost 10 watts has been pretty common, depending on the power settings, and in the case of digital, the output volume of the computer’s sound card. I’m not sure if these high power levels are damaging to the radio, and I like to keep to the spirit of QRP and stay under 5 watts. In digital modes I can play with the sound  levels and output power, and in CW just the power level, to get down to around 5 watts (or less). The radio is also programmed to adjust it’s power level if the SWR is above 2.5:1. There is no built-in tuner, so fortunately, my dipole system seems to be close enough to resonance to work without a power drop.

The Bottom Line

A last look at the LD-5
A last look at the LD-5

Overall, since I’ve gotten most of the computer interface issues ironed out, I’m extremely satisfied with this radio. My biggest complaint really is the lack of detailed documentation and unresponsive customer support from LNR. There is a basic manual that can be downloaded from LNR, but for the most part, it just describes the buttons and menu items in a cursory way. There is also a user forum on the LNR website, but it is not very active, and it seems no one from LNR spends much time monitoring it. Similarly, an e-mail I sent about a week ago through the website’s contact form has gone unanswered or even acknowledged. If you want a plug-and-play device and expect responsive customer support, be forewarned that you might find the LD-5 frustrating. However, I have been able to sort things out pretty much completely, the CQRLog CAT control issue notwithstanding, in about a week. I have not turned the FT450D on since I’ve gotten the LD-5. I am looking forward to warmer weather when I can get outside with this little rig and do some /P operating.

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