TX issue new HL2

[P deV]

Received my HL2 on May 15, 2026

 

Receive is working OK. However during Transmit relay K2 is clicking.

 

Voltages:

Vsupply: 11.75V

+1V2: 1.195V

+2V5: 2.498V

Vbias: 10.00V

Vop:10.19V

Vpa: 7.98V

 

Based on other messages the following measurements where done with base board only, no N2ADR connected. 

When the relay K2 clicks the Vpa drops as well. Sometime very short (mili seconds, sometimes longer (>100ms). On following scope screens shot Vpa is shown triggered on falling edge, during TX and random switching of K2 during a longer event.

 

During TX the expected frequency is seen on the output with about 22Vpkpk (see screenshot below). When the relays K2 randomly clicks, the output (p9 of K2) drops to 0.

 

At the same time Pin 12 of relay K2 goes unexpected to high (relay off) see screenshot:

Relay K2 seem to operate correctly, however it gets switched randomly at unexpected times during TX. And Vpa drops, maybe gets disabled? 

R117 is in place on the board.

Why is K2 getting disabled randomly and how to fix that. Anything else I should check?

best regards
Paul, LB4PK

[John Williams]

Paul, 

How is the HL2 connected? Are you running your controlling computer on WIFI? The most common relay issue is unreliable delivery of packets to the HL2 that causes the TX latency timer to drop out when the TX buffer empties before the next packet arrives. There are threads here that discuss this issue in depth. Search for WiFi jitter, etc. You can loop up a ping command to measure the jitter, IIRC. 

It is much less common that the relay is failing, but it has happened a time or two. 

John W9JSW

---

From: herme...@googlegroups.com <herme...@googlegroups.com> on behalf of P deV <phs.de...@gmail.com>
Sent: Monday, May 18, 2026 8:33 AM
To: Hermes-Lite <herme...@googlegroups.com>
Subject: TX issue new HL2

 

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[P deV]

Hi John

You are almost correct.  I was not using wifi, but a 1Gbs ethernet with local switch. 

Using SparcSDR on my Mac Mini M1, on the same network, I do not have the relay issue.

The PC is a company Win10 with i7 vPRO. Thinking about it, it might be that the company VPN causes some issues, but it allows local subnet access. Maybe some other company or MS windows setting is causing some issues.

After checking the Network Throttling Index Tweak checkbox (and rebooting 2x), the issue was gone!

thanks!

Paul LB4PK