BATC Forum

Hello all,

i have recenty built a Langstone, after a few issues narrowed down to a poor SD Card, its now up and running , with a couple of problems.

1. Its constantly switching to TX , despite pull up resistor fitted between 3.3v and GPIO pins 11 and 12, this occurs on 2 different PI 4's, grounding pins using the same patch cable with the resistors fitted, instantly switches to TX as expected, any ideas ?.

2. the other thing ive noticed is that it seems to run fine for 4 or 5 mins, then gets slower and slower eventually freezing with screen updates once every 3 or 5 seconds, appears worse if ethernet cable is connected, IP address range is different from Pluto.

Power is supplied by 2 DC DC Converters, 1 for the PI set at 5.2v and 1 powering the screen set at 5.05v.

Had a quick look through forum , but didnt see anyone with similar problem.

TIA

Colin
M0YXR

I have never experienced either of your problems. Transmit can only be selected by grounding the pin on the Pi, the pin on an I2C extender, or touching the PTT button on the screen. Maybe you are getting spurious touchscreen presses. I have also never seen the slowing down you describe. My Langstone often runs all evening without issues, with or without Ethernet connected.
One station previously did have problems when the Ethernet was connected. I don’t think we ever came to a conclusion on that.

It might be worth trying to run both screen and Pi from the same supply, that’s what most people do, just connect the screen to the relevant GPIO pins. Maybe there is some sort of conflict between the power supplies.

Slowing down could be an indication of problems communicating with the Pluto. Again probably power related. Also note the previous posts about not running the Pluto on a hub. It must be directly connected to the Pi and preferably not using a separate supply.


Colin G4EML.

Hi Colin,

Just fyi and in case it's a clue to the other Colin's issue; even after several rebuilds, new SD cards, various microphones and a different Pi4 I still get intermittent delays between tx/rx when I have the Langstone connected to the LAN. It's not as bad/obvious as when we were discussing it before and it's less apparent when using the PTT button on the screen but the effect is still there. It's not a problem for me as I usually run it sans LAN connected.

73, Martin - G4FKK

Thanks Martin, I have had a couple of comments about slow responses but so far I have never been able to reproduce the problem on my systems. Without being able to do that it is difficult to know why it is happening for some people.
I think I may have to write some hardware testing code that can be run to identify the cause of problems. It would be difficult to catch every problem and will take some effort and time but might be worth it in the long run.

Colin.

Please specify a value of pull up resistor? I could guess 1K or 10K but as I'm sure.

Regards

David M0YDH

Hi David

10K would normally be adequate, but if you suspect problems (electrical noise or insulation leakage), go for 1K.

Dave

Hi David,

As Dave says pretty much any value between 1 and 100K should be OK.
I normally use 4K7.

When I was at College one of the lecturers always used to jokingly say "Every circuit has at least one 4.7K resistor" He wasn't far off the truth!

Colin G4EML