That still may be the case, and it sure is for the KRC2, but there seems to be enough delay in the K3 reading the AUXBUS line that turning them on at the same time works OK for me.
-----Original Message----- From: Phil Wheeler [mailto:w...@socal.rr.com] Sent: Friday, June 06, 2014 5:16 PM To: Cady, Fred; Elecraft Reflector Subject: Re: [Elecraft] KAT500 assembly Hmm .. I thought I read that the KAT500 must be turned on before the K3. Is that old info? Phil W7OX On 6/6/14, 4:05 PM, Cady, Fred wrote: > Don's suggestion of a 12 v relay is a good one but if you don't want to go > that route, the rigrunner power pole distribution box with auto outlet turn > on (http://www.westmountainradio.com/rigrunner.php) works well. When you > turn on the K3 it can turn on 10 other items. I use it to turn on the > KAT500, the P3, a KRC2, a W2 and probably other stuff I can't remember. > Cheers, > Fred KE7X > > > > -----Original Message----- > From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of > Don Wilhelm > Sent: Friday, June 06, 2014 4:50 PM > To: GDanner; Mike Reublin; Slava Baytalskiy > Cc: Elecraft List > Subject: Re: [Elecraft] KAT500 assembly > > George, > > Yes, the current from the K3 12V output is limited to 500 ma. for older K3s > and 1 amp in later K3s. Older K3s can be upgraded with the Elecraft kit to > provide 1 Amp capability. > > The KAT500 spec maximum draw is determined by how many relays are being > activated by any particular antenna solution, so I would use the maximum > value for the design point because you do not know which L/C combinations > will be necessary for any particular antenna, and yes that maximum is greater > than what the K2 12V output can supply (even with the upgrade). > > I would suggest that you power your KAT500 directly from your power supply > rather than trying to use the K2 12 volt output. > > If you wish to use the K3 12 volt output so the power to the KAT100 (and > other accessories) would be powered on when the K3 is turned on, I would > suggest that you use the K3 12V output to drive a relay, whose contacts in > turn provide power to those accessories (KAT500 included). > > Safety note - install fuses in each power cord (near the power source) with > the fuse rated at 1.5 to 3 times the maximum expected current draw by that > device. In-line fuseholders can be obtained an auto parts store. I prefer > the ATC-3 blade type fuses, but YMMV. > > 73, > Don W3FPR > On 6/6/2014 4:07 PM, GDanner wrote: >> My understanding is the KAT500 will overcurrent the K3 Aux DC output. >> The KAT500 specification is 1.5A max (200 mA typ) from my IB (page 2 >> Rev B3 Nov 20, 2012. The 200 mA should be ok but the 1.5A is greater >> than the K3 1 amp mod is rated for. >> >> I power my KAT500 from my station power supply. Therefore it comes on >> prior to the K3; as required by the KAT500 IB (page 3 item 2 under >> Elecraft K3 Transceiver and KPA500...). >> Also see !IMPORTANT: note on the top of page 10 - "If you are using >> the KAT500 with an Elecraft K3 transceiver connected using the DB15 >> cables as shown I Figure 1 or Figure 2, you must apply power to the >> KAT500 before turning the K3 on. >> 73 >> George >> AI4VZ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
