[Elecraft] [K3] Will I Lose the 120 Watt Max If IupdateTheSoftware?

[Joe Subich, W4TV]

> Even with 3 x 3-500s in my LK550 and 2,900V no load, I only 
> need about 25-40W input depending on band to reach our legal 
> limit: 500W.  Which is plenty, way too much in fact for the 
> digital modes.

In some jurisdictions the limit is lower (e.g., 400 - 500 W 
input) than the US (1500 W PEP Output).  On the other hand, 
in some jurisdictions it appears to be unlimited <G>. 

> > Part 97.317(a)(2) limits the maximum gain to 15 dB
> > (approximately 50 W drive for 1500 W out).
> 
> Not in NZ.  Is there really a max gain regulation in the US?  
> How quaint!

Yes, that's part of the old rules designed to prevent the 
misuse of amateur amplifiers on 27 MHz. 

> ... The difference will be small in pure signal strength 
> terms but sure the operator's confidence is improved.  

True, the difference between 1300 and 1500 W is 0.8 dB. 

However, there is one other issue with the 110 W limit. 
Due to the "slope" in the internal wattmeter, it may not 
be possible to achieve even a "full" 100 W output (much 
less 110 W) on 6 and 10 meters if the K3 wattmeter is 
calibrated on 20 meters. 

73, 

   ... Joe, W4TV 
 



> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net 
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Gary Hinson
> Sent: Monday, September 21, 2009 3:19 AM
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] [K3] Will I Lose the 120 Watt Max If 
> IupdateTheSoftware?
> 
> 
> > Most 3-500 based amplifiers with 2800 V (no load) on the plates
> > require 120 Watts or so for "legal limit" output.  That's about 
> > 11 dB gain.  
> 
> Even with 3 x 3-500s in my LK550 and 2,900V no load, I only 
> need about 25-40W input depending on band to reach our legal 
> limit: 500W.  Which is plenty, way too much in fact for the 
> digital modes.
> 
> > Part 97.317(a)(2) limits the maximum gain to 15 dB
> > (approximately 50 W drive for 1500 W out).
> 
> Not in NZ.  Is there really a max gain regulation in the US?  
> How quaint!
>  
> > The extra 10 to 20 watts of drive makes a difference for those
> > who have SB-220, TL-922, AL-82, AL-1300, AL-572, etc. amplifiers. 
> > It can mean another 200+ W output.  
> 
> ... The difference will be small in pure signal strength 
> terms but sure the operator's confidence is improved.  A 
> cheaper option (as used by certain CBers) is to tweak your 
> power meter to read high.
> 
> Seriously, though, a bit more attention to operating skills 
> and maybe a little investment in your antennas and feeders 
> will eclipse the QRO option every time.  #1 DXing tip is 
> simply to be very active and
> listen hard.   #2 is to save up those tenths of dBs you get for free
> by eliminating unnecessary coax connectors, and indeed 
> unnecessary coax.  Someone should start giving out 0.1dB 
> savings stamps and a DXers' collector's card.
> 
> 73
> Gary  ZL2iFB
> 
> 
> 
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