Burns,

How do you do the conversion? I was looking at the datasheet last night and thinking about this issue.

In Jonathan’s Pi code I believe he prints out the raw register value.

I believe the datasheet indicates each step in the register is x db or dbm but no indication that I saw as to where 0dbm resides in the values.

Research topic for the weekend.

Jim McCullers

WA4CWI

From: Chris Thompson via pacsat-dev pacsat-dev@amsat.org Sent: Friday, April 28, 2023 1:32 PM To: Burns Fisher (AMSAT) wb1fj@fisher.cc Cc: pacsat-dev@amsat.org Subject: [pacsat-dev] Re: AX5043 deafness

These are the raw RSSI values I think. It is the direct value from the AX5043_RSSI register. The data sheet does say it is in dB, but that makes little sense to me.

73

Chris

On Fri, Apr 28, 2023 at 2:26 PM Burns Fisher (AMSAT) via pacsat-dev <pacsat-dev@amsat.org mailto:pacsat-dev@amsat.org > wrote:

I wonder if I have the conversion wrong for RSSI? I'd think it would be NEGATIVE. As I recall in orbit we wanted the reception to be around -100dBm.

73,

Burns Fisher, WB1FJ

AMSAT(R) Engineering -- Flight Software

On Fri, Apr 28, 2023 at 2:12 PM Chris Thompson via pacsat-dev <pacsat-dev@amsat.org mailto:pacsat-dev@amsat.org > wrote:

Yep, good idea Rich.

In my test setup the RSSI for 70cm is about 180. For 2m it is 200. Maybe it is too strong and causing distortion? Do we know the valid range?

To test I put in 10dB and then 20dB of attenuation and dropped it to 190 and then 180 but it is not more reliable. The background noise is hovering around 150.

73

Chris

On Fri, Apr 28, 2023 at 12:10 PM Rich Gopstein via pacsat-dev <pacsat-dev@amsat.org mailto:pacsat-dev@amsat.org > wrote:

For fun, you can check the RSSI while receiving on both bands. Might tell you something...

On Fri, Apr 28, 2023 at 12:04 PM Jim McCullers via pacsat-dev <pacsat-dev@amsat.org mailto:pacsat-dev@amsat.org > wrote:

Chris,

I assume you are referring to packets you are generating locally.

I’ve only tested with the Pi boards and noticed no difference with locally generated signals between the 70cm board and the 2-meter board after getting the frequency correct.

My 2-meter Pi board appear a bit deaf on signals from the local APRS digipeters.

Guess I need to get the LaunchPad set up.

I’ll review the schematic on the daughter board but the schematic should be identical to the Pi schematic.

Let me explore.

73

Jim

Jim,

I have the AX5043 working on 145.835. It ranges correctly and receives packets. At least it receives them some of the time. It seems to be quite deaf compared to wje it was working on 436.8, which is my 70cm RX frequency That receives every packet without error.

I had the same issue on 70cms until you told me to tweak the frequency. But with the TXCO it seems to be right on frequency. I ran a test to TX on the RX frequency and it seems to be correct according to my TinySA.

thoughts?

73

Chris