[Elecraft] my KPA1500 and 160M

[Bill Johnson]

I would agree that the coil could overheat.  The model number is left out.  The Balun Design coil chosen may not be satisfactory for your power despite the 5KW rating.  Which Balun are you using?

Bill
K9YEQ

-----Original Message-----
From: elecraft-bounces at mailman.qth.net <elecraft-bounces at mailman.qth.net> On Behalf Of David Gilbert
Sent: Tuesday, September 1, 2020 12:28 PM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] my KPA1500 and 160M


One distinct possibility is that the 4:1 balun is getting hot at 1500 watts.  Have you tried running the KPA1500 at a lower power?

73,
Dave  AB7E



On 9/1/2020 9:36 AM, w5sum at comcast.net wrote:
> This morning I put up a W7FG true ladder line 160M doublet.   Upon 
> testing, the K3 internal atu does great, matches at 1.3:1.  But when I 
> throw the KAP1500 in line, it gets all pissed off, throws up and 
> faults out.  Says SWR is 99:1 !!!
>
> The Antenna:  The Apex is at 50'.  It is in a inverted Vee config, 
> with both ends approx 20' off the ground.   I'm using 59' of the 600 
> ohm true ladder line to a Balun Designs 5KW 4:1 Balun. This is fed 
> with 22' of Wilson LMR400
>
> Both the K3 internal atu, AND the KPA1500 internal atu get a great 
> match on 80M, 1.2:1   with no issues.
>
> Honestly, most of the work on 160M is FT8 running 20 watts or less, so 
> just using the K3 to get a successful match on 160M is fine
>
> I just wonder why the KAP1500 doesn't like the same antenna the K3 likes.
>
> Any ideas here fellers?
>
> thanks and 73
>
> 73 and GL OM DE w5sum

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