[TowerTalk] 1dB more RF Power?

Jim Brown jim at audiosystemsgroup.com
Fri May 1 03:35:18 EDT 2020


On 4/30/2020 5:40 PM, Bob Shohet, KQ2M wrote:
> Every DB matters - wherever you can find it.

Absolutely. When the signal is close to the noise, small differences in 
the level of the signal become VERY important. And those half and single 
dB add up. 1 dB from bigger coax or hard line, more/longer radials for a 
vertical, raise a 40M dipole by 5 ft, or an 80M dipole by 10 ft, or turn 
an inverted vee into flat dipole at the same height. Three of those 1 dB 
changes combine for 3 dB (equivalent to doubling the TX power.

Another observation. My friend N6SJ is a DXer, but not much of a 
contester. KQ2M and I are both contesters. Contesters, especially those 
trying to pull a multiplier over a difficult path, have experienced the 
value of a dB, often several times in a weekend. N6ZFO, anther contester 
who's a retired statistician/scientist, says that 1 dB is good for a 
2.6% increase in an ARRL Sweepstakes score; three of those is good for 
8%. Casual operators won't notice the difference, but the other guy 
trying pull you out of static WILL.

On SSB, we can increase our loudness on the other end with EQ and 
amplitude compression. Rolling off everything below 500 Hz adds 3 dB; 
amplitude compression set for 10 dB on voice peaks adds that 10 dB. That 
13 dB is equivalent to multiplying TX power by 200!

73, Jim K9YC





More information about the TowerTalk mailing list