PTT Intermittent Slow Response

[G4FKK]

Hi Colin,

I've been using my Langstone (merged with Portsdown), very regularly for the last couple of weeks and, as I've droned on about before, I'm experiencing intermittent delays between switching from transmit to receive and vice versa, using either the touch-screen PTT or a hard-wired one (with pullup resistor fitted). The external relays I'm using (opto-isolated), click over at the correct time but the RF and red Tx indication hang about for a, seemingly random, time before doing their thing. This intermittency only happens when the Pi is connected to the LAN, otherwise it works perfectly.

I know you haven't experienced this but I've come to the conclusion that it's definitely a "thing". I'm wondering if something in the Pi's ethernet interface is interfering with your programmed-in delay? It's not a major issue because I can always just disconnect the RJ45 but, when it happens, it's surprisingly annoying. The 'extra' delay can be anything up to about a second.

I haven't yet tried disconnecting the internet from my LAN to see if that makes any difference but happy to give it a go if you think it's worth it?

All the best,

Martin - G4FKK

[g4eml]

Hi Martin,

I will see if I can add some debugging code that might identify where the delay is occurring. It may not be easy to find as I can’t reproduce the problem here.

Colin.

[G4FKK]

Hi Colin,

Thanks for your prompt reply.

I've been thinking about this overnight and, before you spend too much of your valuable time chasing something that may not exist, I've come up with some other things I can try...

A fresh build on a new SD card without Portsdown - extensive testing.
If that works then merge Portsdown and more testing.
Linear PSU.
Disconnect internet from my LAN (dangerous should daughter and/or XYL discover what I'm up to).
Wireshark the LAN.
Bespoke shack-only VLAN with QoS? (Arrgghh - too much like work).

No one else has reported this effect so I'm thinking it may just be an issue local to me - although I'm not sure how many other constructors spend as much time blathering away on the radio as I do

Thanks again and 73,

Martin - G4FKK