[Elecraft] K3<-->KPA500 Request

Thu Mar 1 11:45:35 EST 2012

It seems a bit more information is needed here. First, communications between the K3 and KPA is essentially one-way - it goes from the KPA to the K3. While that is the right direction for this kind of information, we run into a problem rather quickly. Auxbus communication tends to be slow and very disruptive to the K3, especially during transmit. We send a minimal amount of information to the K3 in order to avoid problems (none during transmit). It would take major modifications to the Auxbus protocol to move this particular data to the K3 (more and longer data packets), breaking the "not during transmit" edict. The results would not give a satisfactory user experience.

The serial port on the KPA does have this information available (note to W0EB, take a look at the KPA Programming Reference at the Elecraft site) and is the right place for a computer to obtain the info. Using an additional serial port to communicate with, and control, the KPA is actually a good thing - very useful information is available, and you never know when we might release an update (ok, probably not very often).

I am also a Mac person / developer. My Mac mini has a four port FTDI adapter attached. I use three of the ports in my station (so far). One for the K3, a second for the KPA and a third for my KRC2. This allows me to monitor and control my station very well, without encumbering the individual components (notably the K3). How hard would it be for Don to add KPA500 support to MLDX? From my (extensive) experience in Mac development, it should not very difficult at all. You just need to talk him into adding it. Or use W4SMT's fine KPA500 Utility available at the Elecraft web site. It will monitor the KPA quite nicely in a window independent from MLDX. Of course it won't log the power level for you in the MLDX log - only MLDX can do that.

I hope this answers your questions, and explains why the information is not available. At Elecraft we are all about User Experience, providing the best possible. Wayne and Eric have instilled that in not just the products but all the people of Elecraft. We do all we can to make sure things work the way they are supposed to.

Jack Brindle, W6FB
Elecraft Engineering

On Mar 1, 2012, at 7:43 AM, N2BC wrote:

> "when transmitting" is the problem... key the mic and say nothing:  the
> program could determing the TX mode but the output is zero.      I suppose
> the KPA500 could simulate a peak-hold  power function, but the
> implementation would have to be in the KPA firmware, the K3 firmware and
> probably in the application program.  I just write "500" in my log.
> 
> -----Original Message-----
> From: Phil Hystad [mailto:phystad at mac.com] 
> Sent: Thursday, March 01, 2012 9:58 AM
> To: n2bc at stny.rr.com
> Cc: 'Jack Brindle'; 'Elecraft Reflector'
> Subject: Re: [Elecraft] K3<-->KPA500 Request
> 
> It still seems to be a useful feature.   I mean, you usually only "read" the
> power level when transmitting anyway, at least that is what I do.  So, this
> is how it could work that would satisfy me.  Given a K3 power setting, the
> output power of the KPA500 is read when transmitting which can be saved in
> memory on the K3 and thus available via the programming interface.  If the
> K3 power setting is changed, or other changes such as band changes and so on
> occur, then this KPA500 power setting can be cleared to zero until the K3
> transmits again using the KPA500 and thus getting a new value.  Not a
> perfect solution but it seems to be able to work in most situations.
> 
> phil, K7PEH
> 
> 
> On Mar 1, 2012, at 6:41 AM, N2BC wrote:
> 
>> The program is reading the power SETTING on the K3 - not the K3 output 
>> power
>> - is available regardless of mode or if the K3 is transmitting or
> receiving.
>> The KPA500's "power" data is essentially RF forward power and would be 
>> an instantaneous reading... so if the data is requested while in RX 
>> the result is zero...
>> 
>> Bill N2BC
>> 
>> -----Original Message-----
>> From: elecraft-bounces at mailman.qth.net 
>> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Phil Hystad
>> Sent: Thursday, March 01, 2012 9:21 AM
>> To: Jack Brindle
>> Cc: Elecraft Reflector
>> Subject: Re: [Elecraft] K3<-->KPA500 Request
>> 
>> I am also a MacLoggerDX user...
>> 
>> If the KPA500 knows the output power well enough to make it available 
>> on its own serial port then why can't it send that info back to the K3 
>> through the
>> K3-KPA500 interface.  I think the original request is a one with good 
>> technical merit that could be implemented -- maybe without too much 
>> hassle by the Elecraft programmer(s).
>> 
>> 73, phil, K7PEH
>> 
>> 
>> On Feb 29, 2012, at 11:04 PM, Jack Brindle wrote:
>> 
>>> Jim;
>>> 
>>> The KPA does not send its output power information to the K3, so the 
>>> K3
>> would just be guessing. The measured output power _is_ available from 
>> the KPA500's serial port, so it would be much better if MacLoggerDX 
>> were to get this information directly from the amplifier. Make a 
>> request to the author to get him to add KPA500 control to the program. 
>> I'll even volunteer to help Don if he needs it (doubtful - he is good).
>>> 
>>> Jack Brindle, W6FB
>>> 
>>> 
>>> On Feb 29, 2012, at 10:17 PM, Jim Bennett wrote:
>>> 
>>>> I use MacLoggerDX (MLDX) for QSO logging, among other tasks. It
>> interfaces very nicely between my K3 and the MacBook Air laptop. The 
>> K3 passes a lot of data (including power output level) to MLDX and it 
>> winds up in my log. However, when I'm using the KPA500, the K3 only 
>> sends the driving power that it outputs to the amp. What I wind up 
>> with in my log is incorrect. For example, if the KPA500 is in OPERATE 
>> mode and I log a QSO, it'll get reported as a QSO made using 25 watts 
>> or power, instead of the 450
>> - 500 that the amp is putting out. Since the K3 and the KPA500 "speak 
>> the same language" and talk to each other, can the firmware be changed 
>> so that the K3 sends corrected Power Out level to the output data port 
>> when the
>> KPA500 is engaged? As it is now, I have to go back into MLDX after 
>> every QRO contact and change the power field to reflect the actual 
>> power and not the K3's driving power.
>>>> 
>>>> Regards, Jim / W6JHB
>>>> Folsom, CA
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