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LNR FX-4 HF 4-Band SSB/CW QRP Ham Radio Transceiver

FX-4 HF 4-band SSB/CW Ham Radio Transceiver

This tiny HF 4-band trail-friendly portable QRP radio is just the thing for hams who go camping or hiking and even for Amateur Radio operators who climb peaks for SOTA (Summits On The Air).

A couple of months back I read that LNR Precision were about to bring out a small 4-band QRP rig that would handle SSB voice as well as CW (morse code) transmit and receive; so I eagerly filled in the form on their website to place myself on the waiting and notification list for this tiny portable transceiver.

So I was excited when I received an email two weeks ago telling me that LNR Precision had the new transceivers in stock and were accepting orders. However the biggest Australian annual field day event was happening that weekend, so I decided to delay ordering and paying for the new radio until I had seen what Wyong had to show me on Sunday. For all I knew, somebody might have been showing or even selling the radios at the show, which is officially known as the Central Coast Amateur Radio Club (CCARC) field day at Wyong Race course.

However, there was little to interest me at the show this year, and by lunch time I had started the long drive south back to Sydney. Once I was home, I clicked on the URL to go to the “buy” page, and placed my order. The Aussie dollar wasn’t doing well against the US dollar that week, so my all up costs, including the cost of postage to Aussie-land was just a few bucks short of A$600.

The LNW FX-4 QRP HF Radio set up for initial testing

I hooked up the LNR FX-4 QRP HF radio on my dining-room table to check it powered-up okay.

The LNR FX-4 arrived in the post yesterday, and was extremely well-packed in a large cardboard box, with the rig, its microphone and 12v power cable generously cocooned inside multiple layers of thick bubble-wrap plastic. And as I eagerly cut my way into the box and through the wrapping, I picked up what I thought must have been a battery pack from the package. But no, it was the little QRP radio itself, a mere 12.8 oz (374 grams) and with the case measuring just 4 1/8 x 2 7/8 x 1 1/2 inches (10.5 x 7.2 x 3.8 centimetres). Now that’s what I call small for an HF radio that does voice as well as morse code!

I grabbed the nine pages of instructions and made myself a mug of tea and skimmed through the information. Then I hooked up 13.8v DC from a small power supply (that normally powers and charges my faithful Yaesu FT-817ND) and connected a QRP dummy load to the BNC female antenna connector. I then plugged in a small manual morse key, an 8-Ohm mobile extension speaker and the supplied microphone into the LNR FX-4 radio.

After making sure of my power supply connections polarity, I pressed the red PWR button and held it down. The display lit up as the instructions had predicted, and I read the information on the screen. I had version 3.5 of the software, and my power was 13.8 volts. Good.

Then I released the power button, and the power switched itself off again! I tried a second and a third time, and the same thing happened each time. Panic. Was the voltage wrong? No. Was the antenna wrong? No, it was a dummy load. Read the instructions again.  Nothing. I powered the button on again, and discovered that I only need hold it down for three seconds for it to turn on properly; and then I could release the button and it stayed on. Success!

I then connected two random lengths of wire to a little Elecraft T1 auto-tuner. I pressed the tuner’s left button until the little green LED came on and then keyed a CW carrier into the ATU. It whirred for a few seconds and made a close match. I now had a compromise indoor antenna that was at least tuned to the 20 meter band. I could hear a few DX voice signals, and some very faint morse near the bottom of 14 MHz. I tried 30m, retuning the wires and ATU but I heard nothing worthwhile, so I tried 40m. The tuner wouldn’t match that so I had to lengthen the wires a bit before it would bring the SWR down to an acceptable level. I heard a local 40m net with several VK2, VK3 and even VK4 calls conversing happily. I tried to talk to them, but my 5 watts and poor indoor antenna didn’t get out well enough. They could hear that someone was trying to join the net, but no-one else could make out my callsign or any of my details. I tried several times while they all listened patiently, but getting through to them on that occasion was a lost cause.

Size comparison of the LnW FX-4 and the Youkits HB-1B rigs

Compare the sizes of the LnR FX-4 and the Youkits HB-1B QRP HF radios.

I was immediately reminded of when I was living up in remote Queensland (VK4 territory) and tried to use my original FT-817 to respond to the callbacks on 80m at the end of the ARNSW Sunday Morning Broadcast. The announcer could hear me trying to get through but nobody could copy me well enough to even understand my call sign. Back then I was using an old 5-band trap vertical which had never been tuned with an antenna analyzer and which had just a few radial wires on the ground. Tuned radials, raised well-clear of the dry ground would have been far, far better; and maybe I would even have got through. But it is a reminder that 5 watts and SSB needs really good antennas, or exceptionally good (and lucky) conditions to get through.

Sizes compared: The Yaesu FT-817ND and the new LnW FX-4 radio

Sizes compared: The Yaesu FT-817ND (left) and the tiny new LnR FX-4 rig. The Yaesu is a 13-band radio (160m to 10m HF and then 6m, and 2m VHF plus 70cm UHF bands). The FX-4 works on 17m, 20m, 30m and 40m HF bands.

So I haven’t yet done a really meaningful test or comparison of the two rigs, but give me a little time. In less than two weeks Australian Amateur Radio operators will be taking part in the annual John Moyle field day, which involves working portable. And that’s when I plan to take the little LnR FX-4 out to play. Then I can update this rticle with a bit more “hands on” feedback, done under field day conditions.

Until then, 73 from me, David VK2DMH — or since we’re talking QRP power, that should be “72″. Just for you; I guess we could call it a “ham special” discount!  ;-)



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