Topics

Elecraft KAT/KPA 500 power combo help


WB9JPH
 

I have encountered a mind bending problem.

I connected the 101 to the power combo with cables from Elecraft.

Works like a dream on CW.

SSB is a different matter - audio distortion at all power levels above 40 watts - barefoot or with the amp.

I looked over all the connections for being done properly with a good mechanical fit.  All ok there. 

I double checked the antenna and all is well.

Put torroids on all cables.

Tried different mike and mike cables.  Same result.

Here is the strange twist: I found out that IF I disconnect the BKDA15 cable (the cable from Elecraft that runs from the linear connector on the 101 to the control xcvr connector on the KAT) at either the radio (linear jack) end or the KAT end SSB operation returns to normal at any barefoot power level.

Anyone have any ideas?



Paul Lukosius
 

I had a similar problem. 

Elecraft has incorrectly connected pin 8 at the Yaesu end to ground at the KAT500 end. Any rf pickup on this line causes txinhibit to activate. Really hacks up your output waveform. The solution is to open up the connector at the ftdx101 end and cut the connection to pin 8.

I have informed Elecraft of this problem and was told I am the only ham on the planet with this problem. Consequently, they will NOT change the wiring of this cable.

Please lodge your complaint with :
Bob Wolbert bobw@...
Eric  eric@...
Wayne n6kr@...

Please tell them that N9PL sent you. Don’t bother with customer service (unless you like frustration). Their “legendary customer service “ has fallen off a cliff during the pandemic. 

73
Paul N9PL 

On Jan 12, 2021, at 3:00 PM, WB9JPH via groups.io <wb9jph@...> wrote:

I have encountered a mind bending problem.

I connected the 101 to the power combo with cables from Elecraft.

Works like a dream on CW.

SSB is a different matter - audio distortion at all power levels above 40 watts - barefoot or with the amp.

I looked over all the connections for being done properly with a good mechanical fit.  All ok there. 

I double checked the antenna and all is well.

Put torroids on all cables.

Tried different mike and mike cables.  Same result.

Here is the strange twist: I found out that IF I disconnect the BKDA15 cable (the cable from Elecraft that runs from the linear connector on the 101 to the control xcvr connector on the KAT) at either the radio (linear jack) end or the KAT end SSB operation returns to normal at any barefoot power level.

Anyone have any ideas?



WB9JPH
 

Hi Paul:
 
Thank you for the response.
 
Couple of questions:
 
1) How do I identify pin 8 on the cable connector - I’m not at home but I don’t recall seeing the pins numbered?
 
2) So I understand the mechanism of what’s happening can you tell me why this affects only mike audio and not cw?  I have not received complaints on my CW signal even at 400 watts.  When that cable is connected at any power over 40 watts the SSB audio is awful - I can hear the RFI in my audio wearing the headphones with the monitor function on.
 
TU es 73
John


n7awm1@...
 

Wow, 40 watts! Mine at that level will overdrive the amp. I usually only run mine at 20-25 watts and get 400 to 500 watts out of the amp. I use the cable from Elecraft with no problem. Before that I used a custom made one that I homebrewed. It worked great and had a push button for tuning. Wish I could help ya more but mine is all in storage waiting for a new house to move into.
Good luck.
N7AWM


WB9JPH
 

Paul, N9PL, has accurately diagnosed the problem and come up with a fix.

Thank you Paul!

Still waiting to hear from Elecraft about Paul's suggestion.


Eric Swartz - WA6HHQ, Elecraft
 

Hi everyone,

We are incorporating the changes to the Amp top Yaesu cable and new ones shipped from the factory after early next week should have the mod.

73, Eric  WA6HHQ
elecraft.com


Eric Swartz - WA6HHQ, Elecraft
 

Also,  Thank You to Paul for bringing this to our attention!

73, Eric
elecraft.com


Scott Russell - N1SER
 

Hey Eric,

Is this the correct cable and the one you're talking about?

CBL-YAE-BKDA15
https://elecraft.com/products/cbl-yae-bkda15_cbl-cbl-yae-bkda15-yaesu-cable

If so can we clarify if this also includes the AUX cable to connect the KAT500 to the KPA500?

Thanks and 73,

Scott Russell N1SER


Paul Lukosius
 

That’s the right p/n. It includes both cables. 

73
Paul N9PL 
Paul Lukosius

On Jan 14, 2021, at 6:14 PM, Scott Russell - N1SER <serussell@...> wrote:

Hey Eric,

Is this the correct cable and the one you're talking about?

CBL-YAE-BKDA15
https://elecraft.com/products/cbl-yae-bkda15_cbl-cbl-yae-bkda15-yaesu-cable

If so can we clarify if this also includes the AUX cable to connect the KAT500 to the KPA500?

Thanks and 73,

Scott Russell N1SER


WB9JPH
 

Kudos to Paul 

For figuring this out and being persistent 


On Jan 14, 2021, at 5:51 PM, Paul Lukosius <plukosius@...> wrote:

That’s the right p/n. It includes both cables. 

73
Paul N9PL 
Paul Lukosius

On Jan 14, 2021, at 6:14 PM, Scott Russell - N1SER <serussell@...> wrote:

Hey Eric,

Is this the correct cable and the one you're talking about?

CBL-YAE-BKDA15
https://elecraft.com/products/cbl-yae-bkda15_cbl-cbl-yae-bkda15-yaesu-cable

If so can we clarify if this also includes the AUX cable to connect the KAT500 to the KPA500?

Thanks and 73,

Scott Russell N1SER


N4KH-Jim
 

Thanks for the info! I have observed the same problem and I was driving myself crazy clipping on ferrites. Incidently, I saw the problem not just on SSB but on CW and digi modes on at least some bands.

Jim N4KH

 

From: FTDX101D@groups.io <FTDX101D@groups.io> On Behalf Of WB9JPH via groups.io
Sent: Thursday, January 14, 2021 6:20 PM
To: FTDX101D@groups.io
Subject: Re: [FTDX101D] Elecraft KAT/KPA 500 power combo help

 

Kudos to Paul 

 

For figuring this out and being persistent 



On Jan 14, 2021, at 5:51 PM, Paul Lukosius <plukosius@...> wrote:

That’s the right p/n. It includes both cables. 

73

Paul N9PL 

Paul Lukosius



On Jan 14, 2021, at 6:14 PM, Scott Russell - N1SER <serussell@...> wrote:

Hey Eric,

Is this the correct cable and the one you're talking about?

CBL-YAE-BKDA15
https://elecraft.com/products/cbl-yae-bkda15_cbl-cbl-yae-bkda15-yaesu-cable

If so can we clarify if this also includes the AUX cable to connect the KAT500 to the KPA500?

Thanks and 73,

Scott Russell N1SER


N4KH-Jim
 

Well shucks, I thought I had found the fix for this problem. But no, when I took the back shell off the FTdx101 end of the cable, pin 8 (tx inhibit) is not connected to anything. There are wires connected to pins 1 through 7 only.

 

Any other ideas?

 

As is I just leave the cable between the radio and KAT500 disconnected, so manual mode is the only option.

 

Jim N4KH

 

From: FTDX101D@groups.io <FTDX101D@groups.io> On Behalf Of Paul Lukosius
Sent: Tuesday, January 12, 2021 3:30 PM
To: FTDX101D@groups.io
Subject: Re: [FTDX101D] Elecraft KAT/KPA 500 power combo help

 

I had a similar problem. 

 

Elecraft has incorrectly connected pin 8 at the Yaesu end to ground at the KAT500 end. Any rf pickup on this line causes txinhibit to activate. Really hacks up your output waveform. The solution is to open up the connector at the ftdx101 end and cut the connection to pin 8.

 

I have informed Elecraft of this problem and was told I am the only ham on the planet with this problem. Consequently, they will NOT change the wiring of this cable.

 

Please lodge your complaint with :

Bob Wolbert bobw@...

Eric  eric@...

Wayne n6kr@...

 

Please tell them that N9PL sent you. Don’t bother with customer service (unless you like frustration). Their “legendary customer service “ has fallen off a cliff during the pandemic. 

 

73

Paul N9PL 



On Jan 12, 2021, at 3:00 PM, WB9JPH via groups.io <wb9jph@...> wrote:

I have encountered a mind bending problem.

I connected the 101 to the power combo with cables from Elecraft.

Works like a dream on CW.

SSB is a different matter - audio distortion at all power levels above 40 watts - barefoot or with the amp.

I looked over all the connections for being done properly with a good mechanical fit.  All ok there. 

I double checked the antenna and all is well.

Put torroids on all cables.

Tried different mike and mike cables.  Same result.

Here is the strange twist: I found out that IF I disconnect the BKDA15 cable (the cable from Elecraft that runs from the linear connector on the 101 to the control xcvr connector on the KAT) at either the radio (linear jack) end or the KAT end SSB operation returns to normal at any barefoot power level.

Anyone have any ideas?


Paul Lukosius
 

Jim,

When did you get your cable set from Elecraft? Any cables shipped from Elecraft prior to about January 20 will have the incorrect connection to pin 8.

Are you sure you are looking at the pinout correctly? There is NO CONNECTION to pin 1, only pins 2 through 8. So, what you are seeing as pin 1 is probably pin 8.

73
Paul, N9PL


ray sylvester nr1r
 

amazon sells a type j ferrite for 8.00 2.4 inch od  take that cable and wrap it thru the type j ferrite   73    ray