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Author Topic: Who is playing with the Hermes lite 2?  (Read 1155 times)

N2DTS

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Who is playing with the Hermes lite 2?
« on: January 06, 2021, 08:10:29 AM »

How is the performance of the radio?
I have ordered one to try, glad to see a low cost ethernet based sdr instead of the high latency usb radios that are so popular.

Anan no longer makes an inexpensive sdr radio, the 10 and 10E were great as receivers and why they no longer make a small cheaper package like that is beyond me.
RF Space can not seem to make any radios to sell, the sdr-iq with an ethernet interface would rock!

The lowest latency sdr's I have had were the old Flex units on firewire and the Anan radios over ethernet.

The standalone flex 6400m has a good amount of delay through the radio, TX delay is at least 300 ms.
The Elad fdm duo standalone was better, at about 100 ms or less I think.
The 7300 was quite fast I think, from memory under 100 ms?
The G90 is under 100ms, its quite fast.

I expect the Hermes to be good, but it has an FPGA and I think the Anan's and older Flex radios did not and did all the work in the computer.

How is the latency of the Hermes system on a nice I7 computer with enough memory?
Is a good FPGA faster then a fast windoze computer?

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WB8LBZ

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Re: Who is playing with the Hermes lite 2?
« Reply #1 on: January 06, 2021, 09:44:31 AM »

I have one. I have not tested the latency. I tested it with SparkSDR on my wired networked switch. I once owned a Flex 3000 and an Anan8000. The 8000 was a separate network. I had thoughts of using it for a transverter driver but I am not there yet. Setting it up for one transverter is a piece of cake, switching transverters will take some work.

73, Larry  WB8LBZ
El Paso, TX
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N6YWU

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Re: Who is playing with the Hermes lite 2?
« Reply #2 on: January 06, 2021, 11:00:55 AM »

How is the latency of the Hermes system on a nice I7 computer with enough memory?
Is a good FPGA faster then a fast windoze computer?

Run a latency monitor on your Windows PC, and you will probably find that its worse case latency is several orders of magnitude worse than the fixed DSP latency of the FPGA.

CW transmit latency depends on how you connect your key more than anything else.  Connecting a key (and/or keyer with its own sidetone) directly to the HL2 front panel will result in the lowest latency for QSK, under 10 mS.

Direct sampling SDRs for HF have such a high raw ADC data rate that they pretty much require an FPGA in order to reliably send bandwidth reduced IQ data through a typical 1Gbps network connection.  IIRC, the older Flex rigs were much lower sample rate Tayloe direct conversion SDRs, not direct sampling radios.
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N2DTS

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Re: Who is playing with the Hermes lite 2?
« Reply #3 on: January 06, 2021, 11:40:45 AM »

Thinking more along the lines of transmitting voice through the Hermes and listening on an analog receiver to the audio.
With the Flex 6400 standalone radio you can not speak and listen, the delay is excessive.
With the Flex 3000 and 5000 you could hear a slight delay but could do it easy.
Same with the Anan radios, and not even using a real fast computer (I5).

That also works with CW, they got CW to work well by doing tricks in the software to make it real time.

The VERY small Elad fdm duo standalone was quite good, even though the radio was very small.
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KX2T

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Re: Who is playing with the Hermes lite 2?
« Reply #4 on: January 06, 2021, 12:24:43 PM »

Thank you for starting your own thread instead of hijacking's! other treads in this forum!
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N2DTS

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Re: Who is playing with the Hermes lite 2?
« Reply #5 on: January 06, 2021, 01:29:14 PM »

What is the latency though the ftdx10?
Most dsp chips in modern radios seem to add very little delay.
Real sdr radios seem to be all over the place.
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KD6VXI

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Re: Who is playing with the Hermes lite 2?
« Reply #6 on: January 06, 2021, 02:38:13 PM »

The latency on something like the Hermes Lite, where the radio does all the encoding of audio and sending to the transmitter can be mitigated by the sound drivers you use.

BUT, I don't think you'll ever get near 0 latency.

I use AISO drivers for my Hermes Lite, and it has millisecond delay.  The "wdm" drivers had probably 3 to 4 times the delay as AISO.  AISO is the standard within the audio industry for people using sound cards.  This on a P5 with 8 gig ram and a hell of a video card.  I spent my money on the video card so SDRStudio would behave.

--Shane
KD6VXI
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N2DTS

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Re: Who is playing with the Hermes lite 2?
« Reply #7 on: January 06, 2021, 04:23:56 PM »

Thanks for the info.
I downloaded AISO for all  as part of getting ready for the Hermes arrival.

I wonder why the Flex 6400m is so bad in that respect.

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N6YWU

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Re: Who is playing with the Hermes lite 2?
« Reply #8 on: January 06, 2021, 06:28:45 PM »

I spent my money on the video card so SDRStudio would behave.
I run my Hermes Lite 2 spectrum/waterfall graphics on 2 year old iPad, and it has zero issues keeping up with a 60 Hz frame rate.  Anyone with an HL2 and a recent iPad or iPhone, you can email me to request a free iOS Testflight beta test build of the software.
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WB8LBZ

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Re: Who is playing with the Hermes lite 2?
« Reply #9 on: January 07, 2021, 08:56:11 AM »

My DPC Latency checker I used under Windows 7 won't work under Windows 10. What program did you use?

73, Larry  WB8LBZ
El Paso, TX
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N6YWU

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Re: Who is playing with the Hermes lite 2?
« Reply #10 on: January 07, 2021, 02:10:11 PM »

I don't use Windows.  An OS latency utility comes with macOS. For Raspberry Pi's there's cyclictest: https://metebalci.com/blog/latency-of-raspberry-pi-3-on-standard-and-real-time-linux-4.9-kernel/ .

For network testing, the Hermes Lite 2 responds to ICMP Pings. So after you discover its IP address you can do something like ping -i 0.2 -c 100 <hl2_ip_address> to gather some network delay statistics.  This network latency jitter can get pretty bad over WiFi or cellular WAN, something to consider if you want try to operating with your HL2 remote from a coffeeshop.

I was recently checking my HL2's SSB output levels with an oscilloscope.  I'm sure there's a few dozen mS of latency in the SDR software + HL2 FPGA Tx buffers; but if so, I could barely see the lag from microphone to my 'scopes waveform display of the RF.

I will be quite interested in seeing receiver performance comparisons of the HL2 against one of the high-end radios in a low noise level environment, even though the HL2 might be more optimal for stations in a moderate noise floor locale.
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N2DTS

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Re: Who is playing with the Hermes lite 2?
« Reply #11 on: January 10, 2021, 07:37:49 PM »

What about linux instead of windoze, I hear its better (less latency) but how do you load and use it instead of windoze, and does power sdr mrx run on it?
I have a number of unused desk tops to experiment with but I know nothing about ubantu, linux...
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WB8LBZ

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Re: Who is playing with the Hermes lite 2?
« Reply #12 on: January 10, 2021, 09:24:54 PM »

I might be able to but I have 2 Windows 10 machines on my network. I have a Raspberry Pi or two in the tinkering pile but I don't have any immediate plans.

73, Larry  WB8LBZ
El Paso, TX
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N6YWU

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Re: Who is playing with the Hermes lite 2?
« Reply #13 on: January 11, 2021, 06:54:37 AM »

There seem to be ways to configure Linux systems for lower audio latency than the default. I need to experiment with some of these audio configurations on one of my Raspberry Pi’s to see how much they improve things. 

If you don’t know much about Linux systems, setting up a Raspberry Pi for SDR is a very inexpensive way to learn.  I currently have a Raspberry Pi 4 running my Hermes Lite 2 as an multi-band FT8 skimmer and WSPR beacon.

For the lowest audio latency, most audio professionals (recording studios, etc.) use Macs.  My understanding is that this is because macOS is based on top of a Mach microkernel, which is closer to a real-time OS than either Windows or generic Linux distributions.  If you need to run Windows software for your radio, most Macs (except the latest ARM M1 models) can run Windows (and Linux) virtual machines, as well as Mac software.
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N6YWU

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Re: Who is playing with the Hermes lite 2?
« Reply #14 on: January 11, 2021, 07:10:03 AM »

According to reports on the mailing list, people with a Hermes Lite 2 on order should be receiving them Friday, or Saturday, or shortly thereafter.

Network testing and receive-only testing can be done before installing the PCBs in the case.

Let me know if anyone here has any questions about final assembly or setup. I’ve assembled 3. One with the heat spreader in the wrong way; so please read the online documentation to avoid that mistake.  Installing the heat spreader requires drilling one hole in the case. Using a drill press for an accurate hole location helps.
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