thUndeadMod v3.4 - openLRS S**T just got real :)

[Cat695]

Papa its not isolated

Its exactly what was happening to me...on 459/435 and 433

get 200m or so out and then you can hear the motor start stopping (ie RSSI dropping in and out) at about 300 m it just shuts down....

This has happened on 2 x Rx which were (as suggested by Papa) covered in heat shrink to protect the chip

I haven't flown with openLRS since.....

[papa_lazerous]

Strange as I've not had an issue with signal yet, last time I flew I was on the previous FW and my RSSI didn't work properly but I still had solid signal and full control to the limit of my eyesight was flying line of sight testing RTH

[Dennis Frie]

Just updated the spectrum analyzer as promised.
It's now possible to change between raw RSSI, dBm and mW.


http://www.rcgroups.com/forums/showpost.php?p=21329412&postcount=33

[Coyote]

Great work Dennis, much appreciated :)

[Coyote]

Ive scanned my tx on 50mw power, the scan is showing 0,00151mw ? My dbm on it is -25.6308dmb

[Dennis Frie]

Ive scanned my tx on 50mw power, the scan is showing 0,00151mw ? My dbm on it is -25.6308dmb

I'm not quite sure I understand, have you connected your transmitter directly to the spectrum analyzer / OpenLRS receiver? That's a bad idea, as it can't handle that powerfull an input. I have used 1 mw and 3 dB attenautor as max input when testing.

100 mw with 30-60 dB attenauter should also work

[Coyote]

No no, I have the tx in close proximity of the scanner. I`m wondering if there is a formula i can use to transfer the readings from the scanner to work out tx actual output mw 

[Dennis Frie]

No no, I have the tx in close proximity of the scanner. Im wondering if there is a forula i can use to transfer the readings from the scanner to work out tx actual output mw

You should be able to make an estimate if you know your antennas well etc. but I doubt you will get a reliable result. Use a cable and an attenauter, a lot better.

[pk-surfing]

If I can find it I'll bring a 3db attenuator over tomorrow if we end up having a fly.

PK

[Dennis Frie]

Here is a quick test with 30 dB attenauter and 0 dBm output-power.
I get a max-reading at -28.74 dBm, pretty close to the expected -30 dBm.


By the way, 3 dB attenauter should be safe with 1 mw output power, but the RSSI is not reliable/lineary above ~ -10 dBm.

[pk-surfing]

3db is all I have Ian, prob best if you look out for a 30db somewhere cos I reckon it wil be useful to you for testing direct coax link up.

PK

[Coyote]

Yeah db`s going to be a bit too small, cheers anyway, I`ll have a look

[raptor_flyer]

hey bud, cheers for the bug report :) All noted and will be in the next fw update.

Mihai.

thUndead,

Using your code on 459, we are just about to do some serious (airborne) range testing in the next couple of days.

One enhancement request :-

Can you possibly add back in the line (from the original flytron code) in the TX code for future releases :-

if ((transmitted==0) && (channel_count>3) && (channel_count<13))

just before :-

Green_LED_ON;

in the main loop since this ensures it stops transmitting if there's no valid PPM frames coming in.


Also found one very very minor bug :-

#if (TX_BOARD_TYPE == 3)
 
-- deleted lines

    #define Green_LED_ON  PORTB |= _BV(5);
    #define Green_LED_OFF  PORTB &= ~_BV(5);    // Was originally #define Green_LED_OFF  PORTB |= _BV(5);   E.g turns it ON not OFF
   
-- deleted lines

#endif   

It looks like this came from the original Flytron code

Thanks Steve (aka Ghost2212's Dad)

Thanks Mihai,

Just discovered adding the

if ((transmitted==0) && (channel_count>3) && (channel_count<13))

only works if your not using Frequency hopping as it changes the timing of the main
program loop so the TX and RX stop hopping in sync. 

Can't figure out the hoping frequency from your code but I'm sure there's a way to
make sure it detects if the PPM stream has stopped updating and then stop
sending packets so the RX goes into failsafe. I'm sure you can figure out how to do this  :)

Thanks Steve (aka Ghost2212's Dad)

[Devonian]

EDIT

Forget the stuff below, I just found this
http://ukhas.org.uk/guides:rfm22b
and on checking in Mihai's code, I see he uses it.

//This sets up the GPIOs to automatically switch the antenna depending on Tx or Rx state, only needs to be done at start up
radio1.write(0x0b,0x12);
radio1.write(0x0c,0x15);

/EDIT


A snippet I found regarding power and controlling the TX_ANT & RX_ANT pins...
Read the posts regarding this
http://arduino.cc/forum/index.php/topic,50533.15.html

Question for the programmers (especially Mihai as this is his thread).
How do you control the state of those pins, as it seems it is necessary? (last post in the thread indicates a 5db gain when controlling the pin states).

Thoughts people? (I'm no programmer, remember!!).

Nigel.

[Dennis Frie]

I have uploaded a new GUI and a complete sketch for the Spectrum analyzer:
http://code.google.com/p/openlrs/downloads/list

Both the GUI and the code for OpenLRS hardware is changed a bit. It should be a lot faster than previously versions, as the delay and rx-reset have been removed  :P