[CQ-Contest] Impressive demonstration of one dB of signal strength improvement

Barry w2up at comcast.net
Thu Aug 22 17:55:25 EDT 2019


Regardless of speed, it always seems the fade/QRN is synchronized with 
the callsign and you miss the same letters each time  :-)

Barry W2UP

On 8/22/2019 8:27 AM, rjairam at gmail.com wrote:
> I always thought speed was dependent on the length of fades and type of
> burst noise.
>
> Faster would attempt to catch short fades whereas slower would catch longer
> fades but weak S/N?
>
> On topband my strategy is around 20wpm and sometimes slower repeats. On
> higher bands I would go as fast as I can (which isn’t very fast) and then
> slow down for weak signals or ops who have trouble.
>
> Ria
> N2RJ
>
> On Wed, Aug 21, 2019 at 7:38 PM Bernie McClenny, W3UR <bernie at dailydx.com>
> wrote:
>
>> For me, and I suspect for many other Topband ops, when QRN/QRM is involved
>> slower is better than faster! 18-20 WPM is about the right speed.
>>
>> Bernie McClenny, W3UR
>>
>> Editor of: The Daily DX (1997-2019)
>>             The Weekly DX (2001-2019)
>>             How's DX? (1999-2019)
>>
>> Two week trial -
>> http://www.dailydx.com/free-trial-request/
>> https://twitter.com/dailydx
>> 410-489-6518
>>
>>> On Aug 21, 2019, at 4:26 PM, Bob Shohet, KQ2M <kq2m at kq2m.com> wrote:
>>>
>>> I have never had the opportunity before to hear differences in signal
>> strength by 1 db increments.  +1 db is clearly an advantage and a +2 db
>> difference nearly obliterates the weaker signal.  Remarkable.  I wish I had
>> heard this 20 years ago!    ;-)
>>> The differences in copy between different CW speeds is very interesting
>> too.  I suspect that most contest ops will generally do better with the
>> higher speeds unless they are exhausted to the point of mental impairment,
>> in which case the slower speeds might work better.
>>> Thanks for posting this Frank and a special thanks to AB7E for creating
>> these audio recordings with explanations!
>>> 73
>>>
>>>
>>> Bob, KQ2M
>>>
>>>
>>>
>>> From: donovanf at starpower.net
>>> Sent: Wednesday, August 21, 2019 11:15 AM
>>> To: cq-contest at contesting.com
>>> Subject: [CQ-Contest] Impressive demonstration of one dB of signal
>> strength improvement
>>> These recordings are an impressive demonstration of the benefit of
>>> one dB of signal strength improvement in a weak signal situation.
>>> Click on the links on this website:
>>>
>>>
>>>
>>> www.ab7e.com/weak_signal/mdd.html
>>>
>>>
>>> 73
>>> Frank
>>> W3LPL
>>>
>>>
>>> ----- Original Message -----
>>>
>>> From: "David Gilbert" <xdavid at cis-broadband.com>
>>> To: elecraft at mailman.qth.net
>>> Sent: Wednesday, August 21, 2019 7:02:21 AM
>>> Subject: Re: [Elecraft] KPA500 Coax size requirements
>>>
>>>
>>> That's not a universally true statement.
>>>
>>> Several years ago I was trying to decide which antenna to buy, and my
>>> choice came down to two antennas that were 2 db apart. I created some
>>> audio files by recording typical band noise and then overlaying them
>>> with recorded CW messages at various strengths. The difference between
>>> 1 dB above the noise level and 2 dB above the noise level can make the
>>> difference between no copy and copy. The files and testing methodology
>>> can be found here:
>>>
>>> http://www.ab7e.com/weak_signal/mdd.html
>>>
>>> If you're ragchewing it doesn't matter, but if you're trying to make a
>>> contact and your signal is at the level of the mud it does.
>>>
>>> 73,
>>> Dave AB7E
>>>
>>> On 8/20/2019 9:18 PM, Jim Danehy wrote:
>>>> ONE DB loss is the LEAST DETECTABLE amount a human can detect. Hardly
>> if not impossible to notice.
>>>> Jim
>>>> W9VNE/VA3VNE
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>>> CQ-Contest at contesting.com
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