[Elecraft] K3 Strange Power Output Problem

[Don Wilhelm]

Frank,

You still have the K3 Low Pass Filters to deal with.
The KBPF3 in the sub and the use of a separate RX antenna may produce 
better results.

But then Wayne is the guy to say what other obstacles might be in the way.

73,
Don W3FPR

On 5/13/2018 7:45 PM, donovanf at starpower.net wrote:
> Hi Wayne,
> 
> 
> The MARS to ham band K3 cross-band problem affects every band,
> but it was extremely severe on 30 meters because the NSS assigned
> frequency -- 9448 kHz -- was almost 700 kHz from our typical
> 10128 kHz receiving frequency.
> 
> 
> Since switching between the K3 bandpass filters and the KBPF3
> band pass filters at T/R rates isn't a workable solution, how about
> this external BNC cable solution since my K3 transceivers have
> KRX3 sub receivers?
> 
> 
> If I understand the K3 internal receiver antenna switching correctly
> a single external BNC jumper cable allows the K3 to transmit and
> receive on VFO A on MARS frequencies and listen to any amateur
> band on the sub receiver:
> 
> 
> - Connect the RX ANT OUT connector to the RX ANT IN connector
> 
> 
> - Tap the main RX ANT button which connects ANT 1 to the RX ANT OUT
> connector and switches the input of the main receiver to the RX ANT IN
> connector (connected by the external BNC cable to RX ANT OUT)
> 
> 
> - Tap SUB to turn the sub receiver on
> 
> 
> - Hold BSET and tap ANT to set the sub receiver input to MAIN. This
> allows the subreceiver to listen on the RX ANT connected to the main
> receiver.
> 
> 
> I'm sorry I didn't think of this yesterday...
> 
> 
> tks
> 
> 
> 73
> Frank
> W3LPL
> 
> 
> 
> 
> 
> 
> 
> ----- Original Message -----
> 
> From: "Wayne Burdick" <n6kr at elecraft.com>
> To: "Elecraft" <elecraft at mailman.qth.net>
> Sent: Sunday, May 13, 2018 4:06:51 PM
> Subject: Re: [Elecraft] K3 Strange Power Output Problem
> 
> I have to admit, operating SPLIT between a ham band and a MARS band that falls outside the nearest ham-band filter isn’t something that occurred to me when writing the firmware. But I can change the filter selection algorithm to accommodate this case as long as a KBPF3 module is installed.
> 
> Technical details:
> 
> Since the K3/K3S is a downconversion superhet, we use very narrow ham-band filters. One of the narrowest is the 30 meter filter.
> 
> To preserve the rig’s exceptional dynamic range, we switch the band pass filters with relays, not diodes. This means we can’t switch filters at T/R rates.
> 
> So to handle the case being discussed, we’d have to select the 7-10 MHz KBPF3 filter for both RX and TX.
> 
> 73,
> Wayne
> N6KR
> 
> 
> ----
> http://www.elecraft.com
> 
>> On May 13, 2018, at 6:10 AM, Wes Stewart <wes_n7ws at triconet.org> wrote:
>>
>> Another reading comprehension problem.
>>
>>> On 5/12/2018 1:36 PM, Mark E. Musick wrote:
>>> Hi Ed,
>>> You don't have a transmit problem at all. It is not an anomaly.
>>> The amateur band starts at 10.100 MHz. You shouldn't be transmitting below that frequency.
>>>
>>> Hello,
>>> I noticed this power output anomaly today while trying to work the NSS station. My K3 was in split mode, transmitting on 10.113.5.
>>
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