Re: [Elecraft_K3] K3S 630 Meter Quandry


Mel Farrer <farrerfolks@...>
 

Yes, 5 W ERP Effective Radiated Power, not transmitter power.  Many of the antennas on 630 Meters are down many dB.  So the input power allowed to the antenna is realitive to the radiation loss.  If the calculated antenna is -10 dB you can run 50 watts into the antenna port.   


Mel, K6KBE



From: "'Mal Speer' malco@... [Elecraft_K3]"
To: Elecraft_K3@...
Sent: Saturday, December 30, 2017 6:49 AM
Subject: RE: [Elecraft_K3] K3S 630 Meter Quandry

 
I think the max power on that band is 5W
 
From: Elecraft_K3@... [mailto:Elecraft_K3@...]
Sent: Friday, December 29, 2017 5:12 PM
To: Elecraft_K3@...
Subject: Re: [Elecraft_K3] K3S 630 Meter Quandry
 
 
I h ave designed and build MANY station control console with DDS and buffer linear amplifiers to drive TX.  There is nothing wrong in constructing a station in such a manner and be legal.  What seems to be at issue is a after market amplifier with excessive gain.  This is not the case in getting a home built TX chain up to some reasonable level on 630 meters.  IMHO.  And I might be wrong again....
 
Mel, K6KBE
 

From: "Wes wes@... [Elecraft_K3]" <Elecraft_K3@...>
To: Elecraft_K3@...
Sent: Friday, December 29, 2017 2:01 PM
Subject: Re: [Elecraft_K3] K3S 630 Meter Quandry
 
 
The limit is actually 15 dB.  That said, you can't easily get 44 dB of stable gain from a small signal amp let alone a PA.  So you will have to cascade multiple amps.  I suppose if someone commercially supplies a cascade of amps in one box that might fail the FCC 15 dB requirement, but then 97.315 (b)(3) seems to say a such an amplifier could be sold to a radio amateur for use in his station anyway.  I am not, thank God, a lawyer so I might well be wrong about this.

Wes  N7WS



On 12/29/2017 8:11 AM, mfroster@... [Elecraft_K3] wrote:
 
One of the reasons that I purchased the K3S was because it is capable of working the new 630 meter band.  The power output is something less than 1 mw.
 
I kept thinking that there should be a commercial amplifier available sometime, to take this 1 mw signal and amplify it to a usable output.
 
However, what I'm beginning to realize is that with the FCC limitation of 13 db amplifier gain limit, it will never be available.  It would take at LEAST 44 db of gain to get to 25 watts!
 
I realize there is the article:
but this design is non-linear.
 
I know there are some LDMOS devices that have gains in the order of 26 db (BLF188XR for one) and I'm wondering if there are any similar devices, somewhat lower power, that would take the K3S output to a 
respectable RF output in more of a linear fashion.
 
Mike,  W0IH
 
 
 


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