Issue with HL2 in TX

[Kurt V.]

Hi dear friends. 

I was talking with PJ2BB today and he told me his HL2 stopped working. 

He documented the issue with a video which you can find here:

https://www.youtube.com/watch?v=FAgAAMijLb0

I have not seen this issue before. Someone has experienced this issue before? 

Any help is more than welcome. 

Kurt 

De on7off

[Ron Lewkowicz]

Is that the relay buzzing like that?  I've had relay chatter once but nothing like that. A power cycle of the network switch solved the relay chatter in this instance and it has never returned. So, usual things to try... power cycle everything. Try different network cables. Try different software. If possible something like Quisk or PiHPSDR running in Linux. Try ferrites on all the cables.

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

There are several things that can cause HL2 relay buzzing or rattling during attempts at transmitting.  

One possibility is that the TxRx relay on the HL2 PCB has gone bad, and likely needs replacement.  Several HL2's are reported to have required replacement of this relay.  Try tapping on the relay, maybe upside-down, and see if the behavior changes.  

Another common reason for relay clicking is that the network connection between the computer and the HL2 has high latency jitter (not a network speed issue, but a networking buffering issue caused by either the network router or a WiFi access point'), or the network has high UDP packet loss.  If using WiFi, switch to a wired ethernet connection.  Or try using different network cables, network ports, routers, network adapters, or even a different computer.

73, Ron, n6ywu

[Kurt V.]

I have more footage of the issue:
https://www.youtube.com/watch?v=u8ukgU50Aes

https://www.youtube.com/shorts/5kBvF2bygJE

https://www.youtube.com/shorts/S5Ejhm9dwWk

Any one of you guys have any idea? 

I pass the information to PJ2BB as replies come in here. 

Any help is more than welcome. 

I want to also explain Bart that the Hermes community is amazing. So I hope we can make things work for him so we have Curacao with a HL2!. 

Thanks

[Ron Lewkowicz]

Seems he has eliminated most common issues and it's likely pointing to hardware issue now.  Steve seems to check in on this group over the weekend so I imagine he will offer some tips to diagnose the cause.  Hopefully it's just the relay.

[Scott Massey]

Hi Kurt,

Could it be a defective TX relay?  Or, possibly a bad signal to the relay?

It sounds like an AC drive signal is being sent to the coil.  Very weird.

Cheers, Scott

iPad transmission

On May 18, 2024, at 14:09, Kurt V. <kvla...@gmail.com> wrote:

I have more footage of the issue:

--
You received this message because you are subscribed to the Google Groups "Hermes-Lite" group.
To unsubscribe from this group and stop receiving emails from it, send an email to hermes-lite...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/hermes-lite/33bee09f-9e60-494d-8100-7b58b5e2a3a0n%40googlegroups.com.

[Max]

Yes, I've had exactly this when the antenna is very badly matched so I think it's most likely caused by RF getting back into the HL2. I note the SWR is flat out high. Why?

Try it into a dummy load and see if same occurs?

73

Max

[Steve Haynal]

Hi Kurt,

The problem appears to be in the PA. I hear relay clicking, see temperatures going above 50C and high bias currents. The first step is to verify that the problem is in the PA by removing the PA from the chain. Disable the PA and ask you friend to see if there is any power output from the RF1 low power output into a dummy load. In Quisk, the desired settings are seen below for "Enable power amp" and "Disable T/R in low power."

There are additional steps you friend should follow and report back detailed on the no Transmit wiki page:
https://github.com/softerhardware/Hermes-Lite2/wiki/No-Transmit

If this unit was purchased recently, your friend should follow the repair wiki to ensure a warranty replacement if confirmed necessary:

https://github.com/softerhardware/Hermes-Lite2/wiki/Repair

73,

Steve

kf7o

[Kurt V.]

Thanks for all people helping. I am passing the information to PJ2BB. 

One question, what final PA is used in the HL2? Is it a mosfet? 

anu info is welcome

Kurt

[Steve Haynal]

LDMOS device. AFT05MS004

Search this list for more details:

https://groups.google.com/g/hermes-lite/search?q=AFT05MS004

73,

Steve

kf7o