Re: [Discuss-gnuradio] gmsk2 (new tunnel.py)

[Brett L Trotter]

Eric Blossom wrote:
> On Thu, Jun 22, 2006 at 03:32:10PM -0500, Brett L Trotter wrote:
>> I've got two machines with one usrp each using basic tx/rx board pairs.
>>
>> As soon as I start tunnel.py on each and set the ip's, one machine
>> (usually the one started second) starts showing BBBBBBBBBBBBBBBBB.....
>>
>> If i disconnect wires, both sides go silent, reconnect and one or both
>> start showing BBBBBBBBBBBBBBBBb...
>>
>> what is the 'B' anyway?
> 
> 'B' means "backoff".  
> It prints a B everytime it attempts to transmit if it detects carrier.
> 
>> I cannot ping between the hosts.. what am I missing?
> 
> First off, this example will only work with RFX-* daugherboards, not
> the basic tx and rx board.  Why: we currently can't enable/disable the
> transmitter on the basic tx board.
> 
> If using a RFX-* board and you see this, try setting the rx gain lower
> and/or the carrier sense threshold higher.
> 
>   $ tunnel --help
> 
> will give help ;)
> 
> Eric
> 

Thanks for your wonderful help and patience so far.

I've gotten rid of the B's with sufficently high -c options, but ping
still isnt happening..

A:
./tunnel.py --freq 102.0M --bitrate 500k -c 80
(other terminal) ifconfig gr0 10.10.10.1
(other terminal) ping 10.10.10.2
also tried with route add -host 10.10.10.2 gr0

B:
./tunnel.py --freq 102.0M --bitrate 500k -c 80
(other terminal) ifconfig gr0 10.10.10.2
(other terminal) ping 10.10.10.1
also tried with route add -host 10.10.10.1 gr0

both pings fail.. though I'm getting nice Tx: len(payload) messages with
sizes from 42-283 on both sides.

I've got to be missing something silly at this point- i've got cables
between the machines RX->TX and TX->RX cross connect with SMA cable,
though cables are about 1M (I don't have 3M cables just this second).
Could cable length be my problem?

Thanks again.