[Elecraft] Relocating my KPA-1500 - need cable

Thu Jun 2 21:28:28 EDT 2022

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. 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. I do not want to do RF sensing; that’s right out after having used an HF AUTO tuner for a couple of years. 

I really want the exact same functionality that I have with the amp here in the shack, connected via the old Y-Box. The issue here is the noise of the fans is too much for my XYL, who works 12 hours a day just a few feet away from both me and the amp. While running 6m FT8 it’s on fan speed three sometimes for an hour or more and I’ve been told in no uncertain terms that that isn’t going to happen this season.

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.

There are only 3 bands that I regularly need the tuner: 160 above 1850 (which I might use a couple of contests a year at most), 80m above 3825 or below 3650, and 40m SSB. Everything from 30m to 6m is resonant, and the CW/digital portions of the low bands are also resonant and don’t need the tuner. Note that I am using a K3s, not a K4, and have no plans to upgrade. 

 - pjd

From: Bob Wilson, N6TV <n6tv at arrl.net> 
Sent: Thursday, June 2, 2022 8:31 PM
To: Peter W2IRT <lists at w2irt.net>; Elecraft Reflector <Elecraft at mailman.qth.net>
Subject: Re: [Elecraft] Relocating my KPA-1500 - need cable

I would try the 25' to 30' AUX cable.  It will probably work fine.  AUXBUS is only used for automatically setting drive power ("KPA1500 OPER" messages) and recognizing band buttons being pressed on the amp, which you will not be doing, plus rig frequency setting the KPA1500 tuner to the right segment, though RF-sensing can work for that too.  If you don't use the tuner much, or If AUXBUS gives trouble, change radio type from K4 to BCD, and use the same long AUX cable.  If that doesn't work, a long RS-232 to 3.5mm TRS cable can be used to track K4 frequency.

A long ethernet or a WiFi to Ethernet extender will provide KPA1500 Remote software connection capability, though you may want to set up your Router to assign a fixed IP address to the KPA1500.  KPA1500 Firmware updates still require a local USB cable, but you can temporarily use a WiFi-enabled laptop for that.

73,

Bob, N6TV

On Thu, Jun 2, 2022 at 5:04 PM <lists at w2irt.net <mailto:lists at w2irt.net> > wrote:

I'm not familiar with CAN-bus. How can I easily implement this in my setup? End result is I want two way CAT control -- amp gets band/frequency data from the radio, KPA-1500 remote app gets SWR and power from the amp to display on the PC and control the power switch and standby/operate from the remote app.

 - pjd

-----Original Message-----
From: jerry <jerry at tr2.com <mailto:jerry at tr2.com> > 
Sent: Thursday, June 2, 2022 3:20 PM
To: lists at w2irt.net <mailto:lists at w2irt.net> 
Cc: 'Jack Brindle' <jackbrindle at me.com <mailto:jackbrindle at me.com> >; 'Elecraft Reflector Reflector' <elecraft at mailman.qth.net <mailto:elecraft at mailman.qth.net> >
Subject: Re: [Elecraft] Relocating my KPA-1500 - need cable

On 2022-06-02 11:23, lists at w2irt.net <mailto:lists at w2irt.net>  wrote:
> I hadn't considered that! Is there a preferred way of doing this over 
> longer distances? I'm sure I'm not the only person who's needed to 
> remote the amp.
> 
>  - pjd

As a homebrew project, if you want "robust" and "just works", it's hard to beat CAN-bus.  A quick Google confirms that for a baud rate of 250K, it will work up to
820 feet.

              - Jerry KF6VB

> 
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net <mailto:elecraft-bounces at mailman.qth.net>  
> <elecraft-bounces at mailman.qth.net <mailto:elecraft-bounces at mailman.qth.net> > On Behalf Of Jack Brindle via 
> Elecraft
> Sent: Thursday, June 2, 2022 12:30 PM
> To: Elecraft Reflector Reflector <elecraft at mailman.qth.net <mailto:elecraft at mailman.qth.net> >
> Subject: Re: [Elecraft] Relocating my KPA-1500 - need cable
> 
> Using a network connection would be a very good idea. Auxbus is not 
> meant to go 20 feet, and indeed will probably fail at that distance.
> Thus using an alternate method to get frequency info to the amplifier 
> would be a good idea.
> 
> 73,
> Jack, W6FB
> 
> 
>> On Jun 2, 2022, at 10:34 AM, David Decoons <rocketnj at gmail.com <mailto:rocketnj at gmail.com> > wrote:
>> 
>> Hi Peter,
>> 
>> Contact Bob, N6TV. He can make good quality DB 15 cables that are 
>> shielded.
>> 
>> Let me know when you are ready and I can help. Also you can do it as 
>> we discussed on the phone via the network, running a CAT 6 cable.
>> 
>> Call me if you have questions.
>> 
>> 73
>> Dave wo2x
>> 
>> Sent from my iPad
>> 
>>> On Jun 2, 2022, at 11:12 AM, lists at w2irt.net <mailto:lists at w2irt.net>  
>>> <mailto:lists at w2irt.net <mailto:lists at w2irt.net> >
>>> wrote:
>>> 
>>> I need to move my KPA-1500 into the basement, and I've got an 
>>> electrician coming to put in the new outlet next week. But the only 
>>> tricky issue now is finding the correct cable to run to the amp from 
>>> my Y-Box to provide frequency/band data, etc. I will need a cable 
>>> run of about 20 feet, which will need to run behind the wall, down 
>>> into a crawlspace, then through a concrete wall to the new rack.
>>> 
>>> With sub-optimal eyesight and shaky hands, I'm not sure I'd by much 
>>> good making one, but if they're not available easily in the 
>>> aftermarket I guess I can give it a shot. Does anybody know where to 
>>> find a pre-made ~20ish foot long cable, or if not, (a) what pinouts 
>>> do I need, (b) where to source the correct cable to do this 
>>> properly, and (c) what connectors-I'm guessing DB15M and DB15F?
>>> 
>>> 
>>> ----------------------------------------------------
>>> 
>>> Regards,
>>> Peter Dougherty, W2IRT
>>> 
>>> DXCC Card Checker/CQ-WAZ Checkpoint
>>> 
>>> www.facebook.com/W2IRT <http://www.facebook.com/W2IRT> 
>>> 
>>> 
>>> 
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