Topband: Top Band Frequencies

[Richard (Rick) Karlquist]

On 7/4/2023 1:18 AM, Karel Matousek wrote:

> I highly recommend please do not use the exact frequency of the 
> transmitter to two decimal places with TWO ZEROs such as 1825.00 or 
> 18031.00 but rather e.g. 1825.33 or 1831.75.
> Those exact frequencies are much more likely to have interference.
> 73, DX Karel OK1CF
> 

Here in Region 2, the BCB stations are on 10 kHz multiples, so there
are always birdies on 1800.00, 1810.00, 1820.00, 1830.00, etc.,
so those should always be avoided.  OTOH, I have often operated on 
1825.00 and never heard a birdie there.  In the other regions, the BCB 
stations are on 9 kHz multiples, so it is likely that there are
always birdies such as 1800.00, 1809.00, 1818.00, 1827.00, so those 
should similarly be avoided.

Aside from that, on any band, any frequency that is a multiple of 5 kHz
is a risky choice for a contest run frequency, just because those
frequencies are more likely to be occupied, possibly by stations in
your skip zone.  Now, THAT is something I have experienced on 1825 in
contests.  It sounds clear, but then the band opens up and I find it
is already occupied.  It's not physics, but just human nature to pick
a nice round number for the frequency.  Resist that temptation, hi.

Rick N6RK