The Hermes Lite SDR and Thetis software

 

A friend of mine recently bought this little SDR and was really taken with it.  I looked at it and for the price, I couldn't resist buying one.  The overall cost, delivered, was £297 from https://www.makerfabs.com

The Hermes Lite is a nominally 5W SDR HF transceiver (mine peaks at about 3.5W).  It sits on your network via wired Ethernet and connects to your aerial via an SMA connector on the back.  It could not be simpler.  It arrives. in an overpack box containing 3 smaller boxes.  The main board, a subsidiary filter board and the case.  The case is a metal box with screen printed ends.  

You need to mark and drill a hole in the case to accept a shim and bolt for heat sinking.  Simple enough and the bolt is provided. Mark the hole by fitting the main board in and finding the centre with a punch or drill.  Remove the board and drill the hole.  Clean the paint off the case to give the shim a good contact.  you may choose to add some heat transfer paste.

The shim requires filing down a little as it is too tight but it is aluminium and easy to do.  Note the alignment of the shim to avoid damaging the components on the board.

The two boards are connected together with a header block as you can see in the image below left.

That is as hard as it gets.  The boards are very well made and although the tolerances on the front panel are tight, with a little patience the boards go in and you can now complete the case.

Plug in the power lead (not supplied but standard), a network cable and an aerial and the radio is ready to go.

So, how does it all work?

Well you need some software to run it.  There are various packages for just about all operating systems but the one that seems to be the standard for Hermes Lite owners is Thetis.  I installed the main Thetis package and the fork by MI0BOT.  Thetis was designed for the Annan SDR radio and Reid has forked it to work better with the Hermes Lite.  It runs under Windows 10/11 and is simply superb. 

The following page has both links and instructions on what to do.

https://github.com/mi0bot/OpenHPSDR-Thetis/releases/tag/v2.10.3.3

Once you have installed the software, simply start the program.  It will come up and look something like this...

Click the power button top left and it should find your Hermes Lite and power up!  I don't intend to do a tutorial on Thetis here!  Look for ON7OFF on YouTube, his videos are excellent.

I have had the Hermes Lite for a few days now and I am absolutely gobsmacked with the performance.  Features in Thetis like the tracking AGC and NR2 (Noise Reduction 2 is seriously good), multiple variable notches, auto notch, 10 band EQ on TX and RX, Continuous Frequency Compression and much much more make listening a true pleasure.  I have a noise floor of about S8 on 40m and Thetis simply ignores it.  Obviously it can't lose the noise floor but I just do not hear it!

After some experimentation, I am using a cheap Thomann USB ONE microphone.  This looks like a studio mic but isn't ;). It is a USB mic and gives really good results.  Next on my list is a keyer to try the Hermes Lite on CW.  The narrow filters are superb.

New OFCOM licensing rules

 

So it's out.  The new licensing conditions start to filter in towards the end of February 2024.  There are quite a few items to look at but for this post I am going to concentrate on repeater and gateways.  A subject close to my heart as I run 2 repeaters.

The headline news is that from the end of February 2024, *any* licensee will be able to run a power limited gateway without having to apply for a NoV.  Intermediate and Full licensees will be able to do the same for repeaters.  Looking quickly at it, it would appear the gloves are off but such is not the case and a careful look at the new licence conditions is required to fully understand the limitations involved.

The document everyone needs to look at and study carefully is this one..

https://www.ofcom.org.uk/__data/assets/pdf_file/0037/272998/Statement-Updating-the-amateur-radio-licensing-framework.pdf

This is a long document and at the end of it is the new licence terms and conditions.

Let's take the easy stuff first.  You will be able to set up a gateway or repeater (with regard to licence class) with 5W ERP on primary bands with no NoV.  This will be fully unattended.  You will simply use your own callsign for this.  NOTE: 5w ERP.  This means you have to take the loss in the feeder and the gain of the aerial into consideration.  This is simple enough to calculate and there are websites that will automate this process for you.  However, there is no limit to the height of the aerial beyond the normal rules.

You will have to make sure that you are not going to cause interference with anyone else.  You will need to look at the band plan and do your best not to cause issues with anything.  If challenged by OFCOM, you will have to show how you came to that conclusion.

This is fine where we are the primary user.  Where we are the secondary user, 70cm for example, you will still have to apply to OFCOM. in order to gain frequency clearance and possibly to get permission to be unattended.  You cannot just set up a repeater or gateway on 70cm without doing this!

I will paste the relevant sections below to show this.  I have confirmed this by email with OFCOM.  Currently there is no mention of going anywhere else than OFCOM for this but I will report back if I hear anything different.

--------------------------------

Remote control operation

10. The Licensee must ensure that, when operating the Radio Equipment by Remote

Control:

a) any links used for the remote control of the Radio Equipment must be

adequately secure so as to ensure that no other person is able to control the

Radio Equipment;

b) remote control links using Amateur Radio frequencies must use frequency bands

above 30 MHz;

74

c) transmissions from the Radio Equipment can be terminated immediately

promptly; and

d) the Licence Number (as specified above) must be displayed on or next to any

unattended Radio Equipment located other than at the main station address.

---------------------------------

---------------------------------

Unattended operation

11. The Licensee must ensure that, when deploying Radio Equipment for Unattended

Operation:

a) any links used for the remote control of the Radio Equipment must be

adequately secure so as to ensure that no other person is able to control the

Radio Equipment;

b) transmissions from the Radio Equipment can be terminated promptly; and

c) the Licence Number № (as specified above) is displayed on or next to any

unattended Radio Equipment located other than at the main station address.

---------------------------------

Further to these in the draft licence, there is a section A3, Notice of Coordination.  This states the rules when coordination is required between interested parties.  The relevant section for our use is at the top of page 100

There are other points for different bands.

There is currently some confusion about setting up a 5W gateway on secondary bands.  I emailed OFCOM for further clarification and it would appear they are still in consultation about this.  The following is an extract from the email chain.

'We will be releasing further guidance when we make our final decision to vary the licences. We are currently in ongoing discussions with the MOD and CAA concerning clearance requests. At present the existing rules on accessing these bands continue to apply going forward.'

So, as you can see, it is not just as simple as putting a gateway or repeater on 5W ERP and away you go.

Be aware that most hotspots do not support VHF.  You cannot, as above, simply put your hotspot onto your aerial and use it when you take the dog for a walk.  To be honest, you should *NEVER* put a hotspot on a high gain aerial.  The spectral purity of hotspots is poor to say the least!

I have filmed a video about all this and you can find it below.

73 Ian