[Elecraft] New from Elecraft: KPA1500 amplifier with built-in ATU, separate power supply

[john at kk9a.com]

It is very easy to put a hairpin coil on your top band vertical and bring
the resonant SWR to 1:1. This should give you much more usable SWR
bandwidth for the KPA1500. Many commercial tube amplifiers will only
tolerate 2:1 SWR.

John KK9A


>From Wes Stewart n7ws
Fri Apr 21 13:11:12 EDT 2017

I'm not necessarily defining a personal situation.  But almost any 80 or 160
antenna will suffice as an example.

I am currently constructing a vertical for those bands.  The model shows
2:1 on
160 at resonance and >3:1 just 60 KHz away and this is with considerable
ground
loss.  Less loss would equal lower BW.  With quarter wave resonance on 80
at 3.6
MHz it exceeds 3:1 at 3.8 MHz and is nearly 7:1 at 4.0.

Transmission line loss is a non-issue with 7/8" Heliax.