On February 16 2023 I placed an order with Makerfabs of Shenzhen China for a small HF SDR transceiver called the Hermes Lite 2. Note that this is Build #10. There are 3 pieces, the transceiver, the filter board and the case. I received package from DHL on 3-13-2023. That was one day before the DHL tracking predicted.
It is extremely clever! It uses a modem chip that normally is used in cable TV modems, made in huge quantites and is inexpensive. It can run with several pieces of software, on both Linux and Windows, and will run with Thetis.
The transceiver was assembled in less than two hours. That's only half of it however. There's the software setup and configuration on the computer to contend with. My transceiver worked perfectly on power up!
Perhaps the simplest and easiest to install and get running is Simon Brown's SDR Console. Simply download it from the link below and install it, according to instructions in the Quick Setup Guide.
After some detective work I've found the latest versions of Thetis and the Hermes Lite 2 modification code as of 3-10-2023. Here are the links. I've downloaded and use the x64 versions of each.
The software setup is very straightforward. You simply install Thetis 2.9.0.6 from the Github link above. It creates the necessary folders for you. Then you download the 2.9.0.6 b2 files from Github. Unzip the files and move them into a folder of your choice. I renamed the folder to ThetisHL2 and moved it to c:\Program Files\OpenHPSDR\. I made a desktop shortcut to the Thetis.exe file, in that folder, to start the program.
The delivery will be via DHL. My first Hermes took 7 days and this one appears to be on the same schedule. 7 days from Shenzhen isn't bad! Here's what I received.
After unpaking and looking everything over, I attached the rear plate to the bottom part of the case. I removed the HL2 board and slid it in the proper slot in the case, from the front and attached the front plate with the bottom 2 screws. Sliding the main board forward, and making all of the front jacks and holes match up, I could easily see where the heatsink hole should be located. I used a 1/8 inch bit, which fits the hole perfectly, with the sharp end down and twisted it to mark the spot where the heat sink hole is to be drilled.
Removing the front panel and board, I used a center punch and lightly tapped it to create a perfect spot for the drill to begin. I might add that you do not want to hit the center punch very hard. You do not want to dimple or distort the area of the case that will need to contact the heat transfer piece. For the same reason do NOT use a Dremel or other power tool for the job. You need to remove paint not metal and a power tool will be much too aggresive.
After removing the front panel and board I began removing the paint from the area where the heat transfer piece will sit. This area must be very smooth, mirror like, to be most effective. I began with 320 grit sandpaper, checking often by positioning the heat transfer piece to be sure that I was removing paint from a sufficient area. Next I cut a piece of 1000 grit sandpaper to polish the area where the paint was removed. I found that by cutting a strip of sandpaper, as wide at the heat transfer piece and using a pencil eraser to push it back and forth, this was a much easier job than I thought it would be!
Before drilling, I reinserted the board back into the case and reattached the front panel to verify that the center punch mark was exactly where I wanted it.
Next, I turned my attention to the heat transfer piece. All metal surfaces should be as polished as possible to maximize the metal to metal contact area. Yes, I will use heat sink compound but just a very thin coat will be needed. Here are the heat sink surfaces that I also polished with 1000 grit sandpaper. Notice the difference from the picture above, before the surfaces were treated.
Using a new 1/8 bit, I carefully drilled the heat sink hole. I purchased 3x12mm black hardware and it's the perfect fit. Note also that the case is supplied with screws to attach the front and rear panels. Unfortunately they are flat head screws and tightening them will cause the front panel to warp. The front and rear panels are both quite thin and distort easily. The screws are also the 3 mm size and picking up some pan head screws are recommended. My local Menards had a good selection of black metric hardware!
After putting a light coat of Arctic Silver heat sink compound on the mating pieces, I slid the board and heat sink hardware into place and fastened it down. It appears to work quite well. Using a laser thermometer and the inbuilt heat sensor I can verify that the case stays in the range between 30 deg C and 40 deg C during SSB QSO's. I have not tried FT8 with the HL2. The case, to the touch, feels luke warm and even after long transmissions, it never gets close to hot or even warm.
Next, I installed the rear panel, the heatsinks and the connector that connects the harmonic filter and the HL2 motherboard.
I first brought up Thetis. It appears that you must have a microphone plugged into the computer or VAC recognizes what it called an "empty channel"!
Later I heard Jack testing and recorded him and shot him the email. He came back calling me on the air. I had no way to transmit, I thought, but picked up the headset and hit transmit. He heard me!!! 3 watts PEP and nearly 200 miles on 80 meters in the daytime!
I have used Thetis for a couple of years now and because of that, I find it like an old pair of slippers, quite familiar and comfortable. I haven't the time behind the other software yet to be fair. Right now Thetis is my pick!
This morning I used SDR Console on 3660khz. It was different to setup and use than Thetis but easily done. I think the graphics are more mature and extremely flexible and the audio, both transmit and receive is, noticeably better.
I've also used LinHPSDR on Linux Mint 20.2 on the air. It loaded and configured as the instructions say. It was a pleasure to use and quite different than Thetis or SDR Console but it worked well.