116 Mhz LO enable on Windows ?

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KG4ODA

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Jul 19, 2021, 9:59:45 PM7/19/21
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Hi, is there an easy way to set CL2 to 116 Mhz in Windows? I use PowerSDR and don't know how to do linux python stuff.

Thanks,
Anton KG4ODA

Roger David Powers

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Jul 20, 2021, 9:53:22 AM7/20/21
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Hi, Anton.

I haven't seen support in any of the SDR applications to configure CL2.  Maybe someone else knows of such, but in my opinion it's not that likely that a SDR application would have such support.  

I will say that Python is not just a Linux thing, it is often is used on Windows. I added a page to our Wiki on how to use Python from Windows to run our hermeslite.py program.  

That page is:


I'd encourage you to give it a go.  If you can get the basic stuff going, you should be able to copy/paste the code recently posted here to set CL2 and change its values to get the desired output frequency.

Regards,
RDP

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KG4ODA

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Jul 21, 2021, 12:02:02 AM7/21/21
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Thanks, I followed your guide and got it working. Here is a write up of steps required, for those who are like me are new to Python and programming.


Installed Python for Windows. I had to use Win10 PC because my main Win7 PC does not have service pack 1 which is required for Python. I downloaded hermeslite.py and copied to desktop. Before running the code I had to paste this code to hermeslite.py file:

def enable_cl2_116(self):
    """Enable CL2 output at 116 MHZ"""
    self.write_versa5(0x62,0x3b) ## Clock2 CMOS1 output, 3.3V
    self.write_versa5(0x2c,0x00) ## Disable aux output on clock 1
    self.write_versa5(0x31,0x81) ## Use divider for clock2

    self.write_versa5(0x3d,0x00)
    self.write_versa5(0x3e,0xb0)
   
    self.write_versa5(0x32,0x01) ## [29:22]
    self.write_versa5(0x33,0x05) ## [21:14]
    self.write_versa5(0x34,0x4b) ## [13:6]
    self.write_versa5(0x35,0xe8) ## [5:0] and disable ss 
    self.write_versa5(0x63,0x01) ## Enable clock2

Here is what it looked like:
paste_116_code.png


Then go to Run -> Run Module and another window will open:
idle_shell_window.png

So I had to type import hermeslite and hit enter
then type x = hermeslite.discover_first() and hit enter
then comes the function that will enable CL2 output at 116 MHz:
x.enable_cl2_116()
after pressing enter it took few seconds for >>> to appear and
RF output in CL2 was on.

Thanks again for your help. I hope in the future this process can be
automated via client software.

Anton
KG4ODA

KG4ODA

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Jul 21, 2021, 12:56:32 AM7/21/21
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Here are some signal measurements on CL2 at 116 MHz

CL2 direct into 50 ohm load of SA. Level is 9.86 dBm which equal to 13.8 mA RMS which is below 18 mA max load current per datasheet. This suggests that CL2 can be used to drive 50 ohm loads.
Phase noise at 3 kHz RBW is below -80 dB.
116-cl2-lvl-2.png

Here is detailed look at phase noise at 100 Hz RBW.
This could be at the limit of spectrum analyzer performance.
116-cl2-spctrm-2(1).png

And here are harmonics and spurs up to 1Ghz. The right most column called Delta Y shows spurious signal levels relative to 116Mhz fundamental.
116-cl2-spctrm.png

Anton
KG4ODA

Roger David Powers

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Jul 21, 2021, 10:47:08 AM7/21/21
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Congratulations on getting this to work, Anton!  

I'm curious, what is the reason for wanting 116 MHz output?  Perhaps this should be obvious to me, but my morning coffee hasn't kicked in yet.

There are a few different authors of SDR applications reading this list, and perhaps they could be persuaded to add support for CL2 output and/or CL2 input if they were given a list of use cases to code.  I did understand the 10 MHz GPSDO use cases.  

I would get more involved in this area but I am busy in the short term.  

Thanks,
Dave 

Joel Caulkins

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Jul 21, 2021, 11:03:03 AM7/21/21
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"what is the reason for wanting 116 MHz output? "

If I had to guess I would say to drive the mixer in the cheap Ukrainian transverters, https://transverters-store.com/  I have used these with great results except the 116mhz crystal drifts a lot, just a guess.

Joel
N6ALT

KG4ODA

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Jul 21, 2021, 1:54:20 PM7/21/21
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I am testing RF mixer performance for VHF full duplex transverter project to enable use of Puresignal on VHF band. The goal is to make plugin board for HL2 to make it work on VHF and later UHF with Puresignal while paying close attention to IMD and SNR performance.

Minicircuits ADE-2+ output at -10 dBm. Lower output reduces SNR.
ade-2.png

Minicircuits ADE-2+ two-tone output at -10 dBm peak. Higher output level degrades IMD performance.
This is a tradeoff between transmitted signal SNR and IMD.
ade-2_imd.png

Anton, KG4ODA

Mike Lewis

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Jul 21, 2021, 1:58:55 PM7/21/21
to Joel Caulkins, Hermes-Lite

116MHz is the LO for a 2M transverter with 28MHz IF.   I modified my Elecraft and DEMI transverters, among others (15 at last count!) to use external LO, typically from a shared DigiLO PLL coupled to a CPU, digital step attenuator, RF amp and RF switch.  Using the Clk2 at 22Mhz for 6M and 116M for 2M, and maybe even 194M for 222, if clean enough could remove some extra parts.  Still have to get the levels correct for each rig, the right LO port, and the band switching logic to select the right xvtr with the CPU.

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