I learned of a new SDR ham radio transceiver - the Hermes Lite 2 - while listening to a QSO on 40 meters, sometime in early 2023.
I found that it had two very appealing characteristics:
These two features alone were enough to get my attention but, as I listened to QSOs in which hams were using Pure Signal, I was hooked! Using a spectrum analyzer, I envied the "brick wall" (no splatter outside the audio band) and "full-bodied" appearance of their SSB signals.
Further listening convinced me that PureSignal produced a much cleaner and "punchy" SSB signal than any audio compression I had ever heard.
Here is a quote from the HL2 wiki page:
If you want to learn more about PureSignal technology, I invite you to visit : https://raw.githubusercontent.com/wiki/softerhardware/Hermes-Lite2/docs/dl1ycf_hl2.pdf
The following are only available from MakerFabs.com:
Assembling the PCBs into the enclosure is easy. Here is an excellent YouTube demo video that will show you how to do that:
By the way, the video mentions that an ethernet cable is connected between the HL2 and an Internet router. Now, I do not have a router in the shack. It's in the next room. My PC is on WiFi. I could have routed an ethernet cable across to the next room but I chose to test the lazy man's solution first. I plugged the ethernet cable from the HL2 directly into a free ethernet port on my PC. It worked! The PowerSDR software on the PC found the HL2 instantly.
Disregard the use of SDR Console software in the video because it does not support (cannot activate) the PureSignal feature of the HL2.
I recommend using PowerSDR on the PC to drive the HL2.
I insist on the use of Hermes Lite 2's PureSignal feature because that's what makes it stand out from the two other very good QRP SDR ham radio transceivers that I own, namely an Elecraft KX2 and an ICOM IC-705.
I recommend PowerSDR software for the Hermes Lite 2. You can download the OpenHPSDR-PowerSDR mRX PS v3.4.9 MSI installer here.
Here is an excellent tutorial on how to set up PowerSDR for the Hermes Lite 2:
There are other software possibilities to run with the HL2 but I have found that PowerSDR best met my needs which boil down to one thing: being able to use the PureSignal technology available on the HL2!
A short comment on other available software for the Hermes Lite 2 SDR ham radio transceiver. The following do not support PureSignal technology available in the Hermes Lite 2 :
LinHPSDR and PiHPSDR include PureSignal support but only run on Linux O/S.
More software, with support for PureSignal technology, may have become available by the time you read this.
Again, I used the lazy man's solution first. Instead of investigating all kinds of microphones suitable for SSB radio communications with PC software, I decided to try a Logitech model H110 stereo headset with USB connector that I had once used for another purpose.
Now, of course, the audio response from such a microphone is much too broad for the usual 3 kHz wide SSB signal. After a little investigation, I found that in Windows, I could limit the audio output of the Logitech microphone to below 8 kHz which concentrates the audio spectrum that contains most of the useful human voice energy.
On the air reports confirmed that this simple and economical headset microphone was indeed performing well.
When you feel that 4-5 watts output won't quite cut it, you can always add a linear power amplifier to the output of the HL2.
One word of caution here:
You need to install a relay buffer interface between the HL2 keying relay (EXTR) and the amplifier, to protect the HL2 from the transients that the relays in the amplifier generate when keyed. I use a RBI-1A by HamGadgets.com for that purpose. It comes with the appropriate prewired cables.
In my honest opinion, the RBI-1A is a much more straightforward solution!
I use a Xiegu XPA125B "100 watt" amplifier with my HL2 SDR ham radio transceiver. I have put the claimed maximum power output between quotes because, according to an ARRL review of this amplifier by VA2PV, it is best to drive it with much less than 5 watts because it starts to generate a prohibitive amount of harmonics above 70-80 watts output.
Therefore, I only drive it with just enough power from the HL2 to reach about 70-80 watts maximum output from the XPA125B which means about 1-2 watts from the HL2, depending on the band.
I monitor the output with a Daiwa CN-901 SWR/PWR meter because the power value displayed by the XPA125B is not too reliable.
Finally, the XPA125B comes with an internal tuner but I prefer to use a wide range external tuner - in this case a MAT TUNER mAT-125E - with my odd length homemade end-fed antenna.
The Hermer Lite 2 is a very economical SDR ham radio transceiver for the shack capable of outputting very clean and "punchy" QRP SSB using PureSignal technology. The only drawback (for some) is that the PowerSDR/HL2 combination cannot send CW. Sorry.
73 de VE2DPE
7, Rue de la Rive, Notre-Dame-des-Prairies, Québec, Canada J6E 1M9
QTH Locator: FN36gb