[Elecraft] K3 Power out

[Jan Erik Holm]

After measuring the TX IMD on SSB I stopped putting the
radio above 100W.
IMO the K3 should be limited to 100W, it is sad to see
it isn´t.
My advice would be, on SSB never go above 199W, on CW
it doesn´t matter.
Please Elecraft, make a FW change and limit the radio
to 100W, thanks!

/ Jim SM2EKM
---------------------------
Ron D'Eau Claire wrote:
> Hello Gary, and congratulations! Opening up the K3 again is not nearly as
> traumatic as you might think. 
> 
> The POWER control will *ask* for more than the rig can deliver. It's spec'd
> at 100 watts, and that's what is guaranteed. The K3 can make a bit more than
> 100 watts on most bands, but that's all it's spec'd to do. When you set the
> POWER control for a specific output, it tries to adjust the transmitter
> circuits for that output, but can't do it if it's out of their range. That's
> what is happening to you at 120 watts. 
> 
> The absolute maximum power will vary by band and to some extent from rig to
> rig. But since 120 watts is a whole 0.8 dB more than 100 watts, it's not
> significant on the air.
> 
> You're probably crowding that 20 amp supply at 100 watts on some bands. The
> efficiency (and so the current required for a given output power) varies
> from band to band. I'm running a K3 with a 20 amp supply, but I'm near the
> limit on some bands at right on 20 amps for 100 watts out, if the SWR is
> quite low. (Higher SWR's reduce the efficiency so the current goes up!) 
> 
> I don't know whether your supply has a crowbar circuit in it, but my Astron
> does. It lets me know if I push too hard by simply shutting down. I have to
> cycle the power supply mains switch to reset it, then turn the K3 on again. 
> 
> Ron AC7AC 
> 
> 
> 
> 
> 
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Gary Smith
> Sent: Saturday, December 20, 2008 9:04 PM
> To: elecraft at mailman.qth.net
> Subject: [Elecraft] K3 Power out
> 
> Firstly 
> 
> Got the K3 assembled. The transverter board was back ordered and so 
> is the subreceiver so I will be re entering the K3 and adding to it 
> at least twice over the next few months. I'm not looking forward to 
> the disassembly & re-assembly but doing the kit sure gave me a great 
> appreciation for the detail and function this marvelous radio has. 
> Absolutely amazing.
> 
> Kudos Wane & Eric, you surely have an amazing way of looking at 
> things. Most effective and clear.
> 
> With that there are a few questions but in the spirit of one at a 
> time;
> 
> The power supply I have been using in the setup is a Heathkit Power 
> supply which was made for one of their last Transceivers. It's a HP-
> 1144 and offers 20 Amps out.
> 
> After calibrating the K3 I tried getting 120 watts out to the dummy 
> load but after the 50 watt calibration, when I held tune down to see 
> how it read. I only got 102-105W out, not 120, though I set he power 
> out at 120W. I'm wondering if the Heath power supply is lacking and 
> that's the reason for the lower maximum output? It seemed to work 
> well as a backup for the Omni V & corsair.
> 
> Idears?
> 
> Thanks
> Gary
> (One year older as of yesterday...)