Error with benchmark_rx program

I am facing a problem with On receiving side, sometimes
reporting problem with unpack module for payload. I have used the same
program previously too and didn’t have any issue with the same. I am
confused what can be causing this problem. For you information, I am
Ubuntu 7.10 and 8.04 on different desktop machines with GNU Radio 3.1.1
Detailed snapshot of program execution is given below.

Please help me in this matter. Awaiting for a kind response.

  • Sachin

/gnuradio-3.1.1/gnuradio-examples/python/digital$ ./ -f
-m dbpsk -v
Attach and press enter:

gr_fir_ccf: using SSE

bits per symbol: 1
Gray code: True
RRC roll-off factor: 0.35
Costas Loop alpha: 1.50e-01
Costas Loop beta: 5.62e-03
M&M mu: 0.50
M&M mu gain: 1.00e-01
M&M omega: 2.00
M&M omega gain: 2.50e-03
M&M omega limit: 0.01

Receive Path:
Using RX d’board A: Flex 2400 Rx MIMO B
Rx gain: 45
modulation: dbpsk_demod
bitrate: 500kb/s
samples/symbol: 2
decim: 64
Rx Frequency: 2.4G
Warning: Failed to enable realtime scheduling.

ok = False pktno = 3971 n_rcvd = 996 n_right = 0
Exception in thread Thread-1:
Traceback (most recent call last):
File “”, line 460, in __bootstrap
line 164, in run
self.callback(ok, payload)
File “./”, line 61, in rx_callback
(pktno,) = struct.unpack(‘!H’, payload[0:2])
File “”, line 87, in unpack
return o.unpack(s)
error: unpack requires a string argument of length 2

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