[Elecraft] Relocating my KPA-1500 - need cable

[lists at w2irt.net]

From: Bob Wilson, N6TV <n6tv at arrl.net> 
Sent: Thursday, June 2, 2022 10:27 PM
To: Peter W2IRT <lists at w2irt.net>; Elecraft Reflector <Elecraft at mailman.qth.net>
Subject: Re: [Elecraft] Relocating my KPA-1500 - need cable

 

On Thu, Jun 2, 2022 at 6:28 PM <lists at w2irt.net <mailto:lists at w2irt.net> > wrote:

Not sure what you mean by “set drive power” this is something I generally do manually, but would love the ability to do it automatically based on band segment.

 

The K3 will automatically memorize and recall the required drive level set on each band, but not each band segment, if you set K3 MENU:PWR SET to PER BAND.  The K3 remembers two drive levels per band, one "barefoot", and the other "when the AMP is ON and in OPER".  

[pjd] OK, I am doing this. I thought there was a way to do it per band segment. 

 

The KPA1500 tuner is set by band segment, but not the drive power. 

[pjd] Yup, that I know. 

 

40m SSB is a problem child for me where a short Yagi means I have to cut back drive power above 7175 or so due to SWR.

 

The K3 will not remember that.  How high is the SWR up there?  I assume you are using the KPA1500 ATU, but if SWR is >3:1, I don't think you can run 1500W even with the tuner engaged.

[pjd] This is exactly what I was trying to address, or hoping to address based on the initial info. Above 7175 or so I’m between 3:1 and 4:1. Above 7250 I’m about 5 or 6:1, and 7295, where too many DX stations listen during phone contests, I’m between 7 and 8:1.  As a result I have to manually back my drive power down to put out about 650-750W PEP, max. The KPA will handle it, but I would love to automate that since invariably I forget to knock the drive down and it errors out. 

I really want the exact same functionality that I have with the amp here in the shack, connected via the old Y-Box.

 

Yes, you will get that by extending the AUX cable, which must be in series with the extension.  I would try the length you need to see if it works.  Chances are it will work fine if you use a quality cable.

[pjd] Just so I’m clear on the concept, you’re suggesting taking my existing AUX cable from the Y-box to the amp on the desk, and adding a DB-15 straight-through extension to it, and connecting the far end of that extension into the relocated KPA-1500 in the basement, yes?

 

I will do an accurate measurement, but I’m pretty sure it’s somewhere between 15 and 20 feet between the Y-box and the proposed location of the amp.

 

Should work fine.  I can supply a 2.5' M/M cable from rig to Y-BOX if you need one.

[pjd] At the moment I have the Y-box plugged into the K3s, with one line going to the amp, and a second line sending band data to my Ameritron RCS-12 automatic antenna switch controller at the base of the tower. At the moment I have no plans to replace that, despite the fact it’s basically junk that doesn’t work automatically when the shack is below 65°F, which is the case all winter long! But I’m trying to see why I would need to change out the cable from the radio to the Y-box. Am I missing something?

Thanks kindly for your advice!

 

On Thu, Jun 2, 2022 at 6:33 PM <lists at w2irt.net <mailto:lists at w2irt.net> > wrote:

Forgot to add in my reply that I have LAN connectivity at the proposed amp location, connected directly from the main switch on the other side of the basement.

 

Great, then you only need one 15-pin cable or one new Ethernet run, not two.

 

73,

Bob, N6TV