Hermes Lite2 Fail

[Fudd Best]

My HL2 has been playng well on all bands and modes for months. Something has failed on 40m and 80m only that results in distortedf/echo SSB/AM transmitted audio. The Thetis MON function has clear nice audio.

Anyone seen this before? LPF/RF something?

Thanks

[ron.ni...@gmail.com]

Check to make sure the relays aren't chattering.  If you hear the relays click more than once when transmitting (or see lots of ep6 errors), you possibly have a bad network connection.  Even very fast networks (often Wifi, cellular, or remote) can have serious problems with latency and latency jitter, and that will cause HL2 Tx to fail.  Another possibility is that RF in the shack is disrupting your network routers or cables only on 40M and 80M, perhaps due to common mode RF on the feed line, or an antenna too close to the "shack" wiring. 73, Ron, N6YWU

[Fudd Best]

Good thoought on RF but my shack is underground and even at 2.5kw, never had RF in the shack. Anyway, I just retested at 1 watt and a 3 foot cable to precision 100 watt dummy. Same distorted and echo audio on 80m and 40m only. Weird.

I also reseated LPF and IO boards to no available. Arrrrrrg! Next to find a Hermes Lite 2 block diagram.

Cheers.

[Greg VKthreeKV]

I suggest it's more likely a software issue and uninstall reinstall latest Thetis 2.10 3.6 Beta5 from MI0BOT GitHub.

If you have saved Data Base they will reinstall in latest update.

Cheers hope you find resolution soon

Cheers,

Greg VK3KV

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[Fudd Best]

Tried that, also fails same on QUISK so likely not THETIS. I also re-insalled firmware to no avail.

I need to find the Hermes Lite2 schematic and matching block diagram.

I spent and hour browsing and failed to find them, cursed and went back to perfection -  Flex 5000 and KE9SN Power SDR.

[Steve Haynal]

Links to the schematic are on the main web page:
http://www.hermeslite.com/

The definitive test to distinguish between software or hardware transmit problems is to connect a CW key directly to the hermes-lite and send with key down. Do you see problems when doing that onr 40M/80M? This is described as part of the no rf out wiki page:
https://github.com/softerhardware/Hermes-Lite2/wiki/No-Transmit

73,

Steve

kf7o

[Fudd Best]

Thanks, will explore but I am getting 4.9 watts out, just crappy audio on 80m and 40m only, high weirdness afoot. Hopfully huuuuuuman error.

[Steve Haynal]

This is software defined radio. There is no modulation happening in the hermes-lite 2 hardware, just IQ data for all modes. If you CW signal is clean on these bands, then the problem is in your software configuration.

73,

Steve

kf7o

[Fudd Best]

Steve,

I was an early Flex 1000 and 5000 user and you are quite correct WRT modulation. VAC and all things audio chain was my first target. I was getting bad on air audio reports YET the Thetis MON button audio was super clean , no distortion/echo. 

I reset thetis DB

I reloaded latest Gateway firmware.

i removed my shack with a 3 foot cable to a precision dummy load at tested with 1 watt.

i tested with QUISK to no avail, same.

All to no avail, why I'm puzzled.

With your deep experience, how is it possibe for MON SSB/AM to be clean and transmitted signal distorted with echo?

I will study schematic today. Is there a Hermes Lite 2 block diagram out there? 

Thanks all,

Randy

W7CPA

[Steve Haynal]

Hi Randy,

Please check with CW. This is a definitive test to see if the problem is in hardware or software. It may be in hardware and then a CW test will confirm that.

73,

Steve

kf7o

[Steve Haynal]

Just to add some more detail here, generating a CW signal from the front panel connector on the HL2 is the only way to generate an IQ signal stream internally for transmit. All other modes require an IQ signal stream from the host. So if you see no distortion in the RF produced by a CW signal from the HL2 front panel, then it is unlikely there is a hardware problem and more likely that the distortion already exists in the IQ signal stream from the host computer.

73,

Steve

kf7o

[Fudd Best]

Thanks, I'll setup a proper test config later today.

Thetis <--> HL2  --> Dummy

Test with CW only keyed from front panel, 1watt out

Monitor with KE9SN PowerSDR and Flex 5000, looking for harmonics or malformed CW sig. 

I'll sent screen shots.

HL2 is a brillant design and has been super solid for 6+ months here, heavy AM work.

RB

[Fudd Best]

Problem solved, nothing to do with HL2, sorry for the noise.

Per Steve,  I setup an isolated test senario and used my KE9SN PowerSDR-F5000 as lab instument.

I have over 8 Alpha Delta switches to support way too many radios.

I removed all bits except HL2, 3 foot coax and a 100 watt dummy load.

Tested all bands at 4 watts out with front panel keyed CM signal.

Perfect signal on all bands. I moved to AM and SBB.

Once again, no HL2 issues, see attached images.

Since I have changed nothing in 6 momnts, and using MON on Thetis showed clean audio, no distortion/echo I was stumped.

I found the problem on my Micro PS50+ PL259 connector.

HL2 <--> PA50+ <--> Dual LDMOS legal limit amp.

A short piece of hamfest coax and its PL259 must have been shorting or opening causing whacked RF on ther way to my final amp. No high SWR was being indicated anywhay to further confuse me.

Once again, sorry for all the noise here.

Cable in now in trash bin.

Glad this weird one has passed.

73 all,

Randy

W7CPA

[Steve Haynal]

Great to hear. Thanks for the update.

73,

Steve

kf7o