DX Audio

[wa2tak]

Ref: Cutting through pileups.

1.  What are the characteristics of DX audio?
2.  How does one achieve it?
3.  What shack equipment does one need to 'check it?'

[Pete, WA2CWA]

author=wa2tak link=topic=48365.msg342452#msg342452 date=1697921002]
Ref: Cutting through pileups.

1.  What are the characteristics of DX audio?
(SSB) Narrow transmitted bandwidth; generally 1.8 KHz
No AM type audio (DX station doesn't care), BIG power

2.  How does one achieve it?
(SSB) If not already installed, buy a 1.8 KHz filter; software defined radios just dial it in
BIG power, Good directional antennas, Luck, Timing

3.  What shack equipment does one need to 'check it?'
(SSB) Multiple successes is a good measure

[W1NJC]

While this doesn't always work, today it's more possible that the DX station has his RX bandwidth open more than 3k.  I've had success running 4k wide when most everyone else is running 3k (or less!).  I get the whole 'narrow your bandwidth to concentrate the power and have more PUNCH' thing, but there have been a few times when as soon as I went to 4k the guy heard me right away.  Generally though there's little value to transmitting any audio below 300Hz or so when trying to work DX SSB.  Next time you can't get through, try a 300 (or even 1k) to 4k filter and see what happens.

[KD6VXI]

VE7RF, of ESSB 'fame' (he did write the literal book) has experienced the same thing.

When using space shuttle audio a contact couldn't be made
  Fatten up the bottom and extend the highs out and good copy OM.

Granted, overdoing it doesn't help, but I like to be over 3.8khz wide when just rag chewing.

--Shane
WP2ASS / ex KD6VXI

[W1NJC]

When rag chewing on SSB I always try to run 4kHz and enjoy it when the other station does too. My default for SSB is something like 50-4000, pretty flat but with a little extra compression on the highs.  People love to hate ESSB, but I think they just don't have a radio that allows the adjustment! 

[kb3ouk]

 What may be happening is by brickwalling the audio at 3k you're cutting out the harmonics of some of those midrange sounds around 1k to 1500, but opening it up to 4k lets those 2nd and 3rd audio harmonics through, increasing the intelligibility.