[Elecraft] K3 Receive Attenuation with KPA500 in Operate

Cady, Fred fcady at ece.montana.edu
Fri Aug 2 07:24:05 EDT 2013


You may both be right! I haven't checked my KPAK3AUX cable for actual wires but I bet there are 15 wires because I know that the pins not to be connected are snipped off in the DE15HD plug-end of the cable. 

-----Original Message-----
From: elecraft-bounces at mailman.qth.net [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of iain macdonnell - N6ML
Sent: Thursday, August 01, 2013 10:00 PM
To: Ron D'Eau Claire
Cc: Elecraft Reflector
Subject: Re: [Elecraft] K3 Receive Attenuation with KPA500 in Operate

That's not what the KPA500 manual says :-

"Elecraft K3 Cable Connections

This is available direct from Elecraft (pg 16): order KPAK3AUX . Pins not shown have no connection."

The table shows only 10 pins.

Elsewhere in the KPA500 manual, it is stated that pin 7 must not be connected to the K3.

I don't have a KPAK3AUX cable to test, as I made my own custom cables.

73,

    ~iain / N6ML



On Thu, Aug 1, 2013 at 7:51 PM, Ron D'Eau Claire <ron at cobi.biz> wrote:
> The KPA3AUX cable DOES connect all 15 pins, Ian. It is simply a 
> straight-through cable, unlike a common VGA cable.
>
> If you want to use a separate PTT line (e.g. to route through some 
> other equipment that needs to control the amp, such as a Stepp-IR 
> controller) you need to use the Key Line Interrupter shown in Figure 2 
> that opens the PTT line in the DB15 cable.
>
> 73 Ron AC7AC
>
>
> -----Original Message-----
> From: dseven at dseven.org [mailto:dseven at dseven.org] On Behalf Of iain 
> macdonnell - N6ML
> Sent: Thursday, August 01, 2013 7:01 PM
> To: Ron D'Eau Claire
> Cc: bwruble at gmail.com; Elecraft Reflector
> Subject: Re: [Elecraft] K3 Receive Attenuation with KPA500 in Operate
>
> Brian was referring to his "cable lineup" (quoted below).
>
> Brian, you do need two HD15 cables.... The point that Fred was making 
> is that one of them needs to be the Elecraft KPAK3AUX, whilst the 
> other one could be a straight-through cable with all 15 pins 
> connected. The KPAK3AUX does not connect all 15 pins, and that's 
> important. There is no harm in using two KPAK3AUX's, and that is 
> actually the safest configuration (cables designed for VGA monitor use will not necessarily work).
>
> The KAT500 should tune when the KPA500 is in operate mode, though - 
> there is a specific configuration for that in the KAT500 Utility. On 
> the "Configuration" tab, click "Edit Configuration...", then in the 
> "Amplifier Key Interrupt Power" tab , click "Optimize for Elecraft KPA500".
>
> 73,
>
>     ~iain / N6ML
>
>
>
> On Thu, Aug 1, 2013 at 6:48 PM, Ron D'Eau Claire <ron at cobi.biz> wrote:
>> Where do you see two DB15 cables in a diagram Brian?
>>
>> Ron AC7AC
>>
>> -----Original Message-----
>> From: elecraft-bounces at mailman.qth.net 
>> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Brian F. 
>> Wruble
>> Sent: Thursday, August 01, 2013 4:57 PM
>> To: Cady, Fred
>> Cc: Elecraft Reflector
>> Subject: Re: [Elecraft] K3 Receive Attenuation with KPA500 in Operate
>>
>> F
>> red, thanks.  I am using that cable both places where my diagram says
>> "DB15 Cable".
>>
>> I guess I needed to have invested in only one.
>>
>> Everything seems to work, and the tuner protection works as well.  I 
>> proved that by lowering K3 output power to 5 watts (just to be safe), 
>> allowing the KPA500 to key and asking the KAT500 to re-tune.  it 
>> refuses to do so.
>> That is the right result.
>>
>> 73,
>>
>> Brian
>>
>>
>>
>> *Brian F. Wruble, C.F.A.
>>
>> *70 is the new 40.*
>> *
>> Mail: 1107 Key Plaza, PMB 447 Key West, FL 33040-4077
>> Summers: P.O.Box 57, 7400 Augustine Herman Highway, Georgetown, MD 
>> 21930 eFax  305.768.0278
>>
>>
>>
>>
>>
>>
>>
>> On Thu, Aug 1, 2013 at 7:08 PM, Cady, Fred <fcady at ece.montana.edu> wrote:
>>
>>> Hi Brian,
>>> Make sure you are using a KPAK3AUX cable somewhere between the K3 
>>> and the KPA500. It can be between the K3 and the KAT or the KAT and 
>>> the KPA.  You can use a full DE15HD cable other places but the 
>>> KPAK3AUX cable needs to be in there somewhere.
>>> Cheers,
>>> Fred KE7X
>>> "The Elecraft K3: Design, Configuration and Operation"
>>> "The Elecraft KX3 - Going for the Summit"
>>> (soon - "The Elecraft K-Line - KPA500 and KAT500")
>>>
>>>
>>> -----Original Message-----
>>> From: elecraft-bounces at mailman.qth.net [mailto:
>>> elecraft-bounces at mailman.qth.net] On Behalf Of Brian F. Wruble
>>> Sent: Thursday, August 01, 2013 4:17 PM
>>> To: don at w3fpr.com
>>> Cc: Elecraft Reflector
>>> Subject: Re: [Elecraft] K3 Receive Attenuation with KPA500 in 
>>> Operate
>>>
>>> Hi Don,
>>>
>>> Thanks for the prompt response.
>>>
>>> Yes, I am using the DB15 and the PTT line.  I got it working.  Here 
>>> is my new cable lineup:
>>>
>>>
>>>
>>>
>>> 1.  ACC on K3 (DB15) >>> DB15 Y Cable | >>>DB15 Cable >>> "XCVR"
>>> (DB15) On
>>> KAT500
>>>                                                                   |
>>>                                                       And      | >>>
> "ACC"
>>> on Navigator Interface
>>>
>>>
>>> 2.  "RS232" on K3 >>> "XCVR" (RS232) on P3
>>>
>>>
>>> 3.  "PC" on P3 >>> "RS232" on Navigator Interface
>>>
>>>
>>> 4.  "AMP" on KAT500 (DB15) >>> DB15 Cable >>> "AUX1" (DB15) on 
>>> KPA500
>>>
>>> 5.  NO PTT LINE into KPA500 or into KAT500
>>>
>>> 6. No "Key Line Interupter" anyplace.
>>>
>>>
>>> With this lineup, is the KAT500 protected from the KPA500 keying 
>>> when the KAT500 is tuning?
>>>
>>> I must admit, I have mightily confused myself in this process.
>>>
>>> Thanks again,
>>>
>>> Brian W3BW
>>>
>>>
>>>
>>> *Brian F. Wruble, C.F.A.
>>>
>>> *70 is the new 40.*
>>> *
>>> Mail: 1107 Key Plaza, PMB 447 Key West, FL 33040-4077
>>> Summers: P.O.Box 57, 7400 Augustine Herman Highway, Georgetown, MD 
>>> 21930 eFax  305.768.0278
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> On Thu, Aug 1, 2013 at 5:01 PM, Don Wilhelm <w3fpr at embarqmail.com> wrote:
>>>
>>> > Brian,
>>> >
>>> > I have heard this before, and as I recall it has to do with the
>>> > DB15 cable and the PTT cable when used together.
>>> >
>>> > Are you using the PTT cable in addition to the cable from the K3 
>>> > ACC cable?  If so, pin 10 of the cable should not be included.  
>>> > See the note on page 8 of the KAT500 manual.
>>> >
>>> > Normally you would not have to use the PTT cable with the K3.  See 
>>> > pages 3 and 4 of the KAT500 manual.  For this arrangement, piin 10 
>>> > of the ACC cable must be present.
>>> >
>>> > If you have other devices that need access ti the K3 Key Out line, 
>>> > you would use the PTT cable AND use the key line interrupter to 
>>> > disconnect pin 10 from the DB15 Interface cable without the need 
>>> > for removing pin
>>> 10. .
>>> >
>>> > 73,
>>> > Don W3FPR
>>> >
>>> >
>>> > On 8/1/2013 4:30 PM, Brian F. Wruble wrote:
>>> >
>>> >> Hi all:
>>> >>
>>> >> I am running a newly assembled "K-Line" --- K3/100, KPA500 and KAT500.
>>> >>  The
>>> >> K3 is pretty "loaded" with KRX3, KAT3, KXV3A, etc.
>>> >>
>>> >> I just noticed that received signals are down 4 S-units when the 
>>> >> KPA500 is in Operate.  In Standby, signals pop right up.
>>> >>
>>> >> Reading past reflector emails on the topic, I found one thread 
>>> >> that suggested this may have to do with the state of the KPA500 
>>> >> PTT.  I found that pulling the PTT RCA plug out ended the problem.
>>> >>
>>> >> Then I replaced the PTT plug, and still had no problem.  However, 
>>> >> once I actually transmitted, and the PTT acted to key the KPA500, 
>>> >> the problem recurred >>> Low sigs when the amp is in Operate, 
>>> >> Full sigs when in Standby.
>>> >>
>>> >>
>>> >>
>>> >
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