[CQ-Contest] contest recording

Jan Erik Holm sm2ekm at telia.com
Wed Oct 12 12:34:53 EDT 2005

Yes Dale, look below.

I would say that the consensus is that one would need 1 GB
to be on the safe side.
I was just after rough figures, i e if we are talking a few
hundred MB´s or 1 or 2 GB´s, 2 Gigs would be on the super
safe side I guess.

73 Jim SM2EKM

Can you compile/summarize and share the responses you received with the rest of 
us, Jan?


dale, kg5u

You can try the Ogg Vorbis compression codec that is better than mp3.



And programs like SOX to record an compress in background, in linux it's
easy cake, just a script.

73, fede.
Hi Jim -

I use Writelog to record the contests.  The setting I use is MPeg-3 32kbs/24000 
hz 3kb/sec.

This will record a 48 hour contest in less than 800Mb and can fit on a CD.

In Writelog, you can click on a QSO and it will play.  However, I seldom listen 
to the recordings at any length.  Mostly, people want to hear how they sound.

I use an 800Mhz machine, but not the one I use for logging/dvk/etc.

GL and 73,

Tom W2SC 8P1A
 From Tips and tricks page:

· Recording is done at 11025 Hz, 8 bit, mono (30 seconds = 250 kB, maximum 30 

Recording uses about 1 GB per 24 hours (40−50 MB per hour). There are programs 
which can compress these wav files to MP3 files but if this can be done at the 
same time when giving CQ depends a lot on the computer used. A clunker will 
surely not do it. There is of course the possibility to do this after the 
contest. Enough harddisk space during the contest is necessary.

Using typical MP3 compression  Writelog uses about 350MB for a 48 hour 
contest... I can look up my settings if you need them..but you can easily store 
a full 48 hours on a CD...
The qualtiy is adequate to hear things you missed real time..which is very 
disturbing when you review your UBN file.

73 Chas K3WW

Maybe someone replied already, but if not, here with WL I recorded the whole
of last years CQWW PHONE and it used about 200 Mbit.


Hi Jim,
Depends on your compression routine.  Using mp3, it is 3 MB/hour and
the number of QSOs doesn't matter because recording is on all the
time.  Without compression it is BIG file.
Barry W2UP
Hi Jan,

I use about 15 meg per hour for stereo, good quality recording for 720 meg,
which fits on one CD-R.

73, Ken, K6LA / VY2TT

I use a computer running linux.  I use sox and lame
to do the recording.  The lame setting I have been
using that gives me the quality that I like uses a little
under 21 Mb/hour.  I restart the recordings at the top
of each hour using a cron job.  I have found it is
much eaiser to deal with 24 or 36 or 48  21Mb files
than it is to mess with one big file.

I am not an expert with lame ... but here is what I have been
using most recently with very good results.

sox -t ossdsp -w -s -r 44100 -c 2 /dev/dsp -t cdr - | \
lame --verbose -r -b48 --scale 3.5 - contest.mp3

Here is the IARU contest first hour:

There are more contests here:

If you poke around in there you will notice that there are some
smaller and maybe larger file sizes - this is because I have been
playing with the lame settings.  Some use VBR and one or two are
mono recordings because I did not notice that I was not recording
in stereo.  I use stereo most of the time since I want to record
the two radio audio.

-- George Fremin III - K5TR
Ett par gigas: ca 8kHz, 8 bit.

48x3600x8000x8 = bits per channel per contest.

Divide by 8 to get Bytes.
Some 1.4 G/ channel.

Jukka OH6LI

Actually it is just the time the recording is on not by the QSO.  The
program just runs in the background.

In Sweepstakes last year I used a program called Audacity.  I don't recall
exactly how much space it took up but it was not staggering.

You need to adjust the sampling rate and bits to a reasonable rate so the
file is not huge but readable.  I will try to find the file size and repost
the size but I want to say around 200mb.

Dale L Martin wrote:
>> Jan Erik Holm wrote:
>>> I´m woundering about how much HD space that might
>>> be needed to record a 48 hour contest, N1MM or WL
>>> software.
>>> I know it depends on how many Q´s one makes but if
>>> someone with experience just could give some ball
>>> park figures.
>>> 73 Jim SM2EKM

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