Hermes Lite V2

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Trevor Hopps

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Sep 25, 2024, 4:07:59 AMSep 25
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Hi, I have a HL2 with N2ADR filter board and love it.
So much so that I bought a second and use them for monitoring ft8, ft4 and wspr.
I live in the Northern Territory of Australia and unfortunately during our wet season we occasionally get lightning strikes in the vicinity.  Induction is always a problem and sadly just killed one of my units.  It wasn't a direct strike but enough current must have come up through the amp/tuner it was connected to (turned off) to damage the HL2 itself.  Now when I power it on there are no lights or signs of life. A visual inspection of the SMD components was uneventful with no blown, destoryed or burnt components visible.  I am wondering if it is worth trying to get a repair or should I just write it off and purchase a new unit?  Thoughts appreciated.

Trevor - VK8TH

Tim ZL3PIE

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Sep 25, 2024, 11:51:08 PMSep 25
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Hi Trevor,

If I was in your shoes, I'd either get it looked at, or perform some further diagnosis. It is possible the fault is coincident with the lightning strike. I'd check voltages around the power supply first, using a current limited supply.

If you get stuck I'm happy to take a look at it, I'm just over the ditch.

Cheers,
Tim ZL3PIE

Clifford Heath

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Sep 26, 2024, 2:15:06 AMSep 26
to Trevor Hopps, Hermes-Lite
It seems likely that your HL2 is toast. There isn’t much protection at the RF input.

Unfortunately we cannot have main power supply *and* an external antenna *and* Ethernet without providing a path for lightning. I lost $10K worth of equipment in a strike some years back, which involved current coming in via cable internet (suspended wires in the street) and back out through main power (also suspended wires), passing through my Ethernet infrastructure and killing everything en route. Everyone in our street had similar damage, so I suspect it cost the insurance companies quite a bit.

Adding radio antennae to that means I have three outside sources - but the street wiring is by far the biggest.

What I’ve done is to create two networks; the external “hot” one and the internal one, with a 10GbE optic fibre isolating them. The radios are on the hot side, but all my IT infrastructure is on the cold side.

I disconnect the antennas when not in use, but I feel that with gas discharge tubes and proper limiter diodes at the radio inputs, I could survive all but a direct strike. In 2019 I redesigned the HackRF to use several Skyworks SMP1330-085LF diode, and if I was revising the HL2 I would do something similar at the receiver input.

Consider putting the radios on battery power to reduce the exposure to mains wiring.

Clifford Heath.

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