[Elecraft] KAT500 Re-Tuning
Cliff Frescura
cf at cfcorp.com
Tue Nov 17 02:38:20 EST 2015
Thanks -this is helpful information. If going the hardware route, I am
inclined to implement the logic via an RS-232 wedge device vs implementing a
BAND0-3 device (basically an antenna switch).
73,
Cliff K3LL/6
-----Original Message-----
From: Dick Dievendorff [mailto:dick at elecraft.com]
Sent: Monday, November 16, 2015 9:36 PM
To: Cliff Frescura
Cc: Cady, Fred; Elecraft at mailman.qth.net
Subject: Re: [Elecraft] KAT500 Re-Tuning
If the band lines are used only, the ATU picks a mid band freq if there is
no history since last ATU power up. On first tx after that, it performs a
memory recall tune using the counted freq.
Power up means DC power applied.
A k3 can provide approx freq on RX thru the ACC cable, depending on a menu
setting
Dick, K6KR
> On Nov 15, 2015, at 16:20, Cliff Frescura <cf at cfcorp.com> wrote:
>
> I went back and reviewed the KAT500 command set and it doesn't look
> like this is possible because the serial protocol does not have a way
> to communicate split status. I've been knee deep in the KPA500 serial
> protocol (with great results thanks to Jack W6FB) and thought they may
> have some high level similarities, but not really.
>
> Do you know how the KAT500 interprets frequency, if driving only the
> band data lines (BAND0-3) via an external TTL device? Does it pick
> middle of the band if there is no last used frequency?
>
> 73,
>
> Cliff K3LL
>
> -----Original Message-----
> From: Cliff Frescura [mailto:cf at cfcorp.com]
> Sent: Sunday, November 15, 2015 2:58 PM
> To: 'Cady, Fred'; 'Elecraft at mailman.qth.net'
> Subject: RE: [Elecraft] KAT500 Re-Tuning
>
> Apparently yes. However, I'm using the KAT500 serial port to
> communicate frequency to the KAT500 via logging software (DXLabs), not
> auxBus, since the radio is not a K3/S.
>
> 73,
>
> Cliff K3LL
>
> -----Original Message-----
> From: Cady, Fred [mailto:fcady at montana.edu]
> Sent: Sunday, November 15, 2015 2:28 PM
> To: Cliff Frescura; Elecraft at mailman.qth.net
> Subject: Re: [Elecraft] KAT500 Re-Tuning
>
> Are you asking for the KAT500 to choose two different tuning solutions
> when operating split? At present it chooses the VFO B frequency for
> its solution according to:
>
> MCU 4.83 / DSP 2.82, 2-8-2014
>
> * FSK-D (RTTY) POWER-CONTROL BUG FIX: Power output can now be
> increased while in transmit mode when using FSK-D.
>
> * KAT500 ATU SUPPORT: Automatic retuning of KAT500 LC network as K3
> VFO is moved. VFO frequency messages are sent via the auxBus. Sends
> VFO A frequency except in SPLIT mode, where VFO B frequency is sent.
>
> Cheers,
> Fred KE7X
> www.ke7x.com for all KE7X Elecraft books.
> ________________________________________
> From: Elecraft <elecraft-bounces at mailman.qth.net> on behalf of Cliff
> Frescura <cf at cfcorp.com>
> Sent: Sunday, November 15, 2015 3:09 PM
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] KAT500 Re-Tuning
>
> Antenna issues specific to the OP aside, there is a valid reason to
> have the
> KAT500 recognize split and inhibit retuning/recall.
>
> The need for this functionality is very apparent when running split on
> 40m SSB when the DX is below 7.1 MHz and listening up much higher than
> 5KHz for anyone using a narrow bandwidth 40m antenna. Consider that
> the KAT500 already tuned the antenna on your TX, so the "fix the antenna
solution"
> doesn't apply. Listening ~50KHz away should not require any retuning
> since the tuner's settings at your TX should be good enough for RX.
>
> Here is how it would work:
>
> 1. When the KAT500 sees a *transition* from split off to split on...
> a. The KAT500 would recall settings for TX Frequency or retune
> (under the VSWR settings condition) when it sees RF for the first time
> after this split transition 2. When split is on (Split mode)
> b. The tuner should not change any settings regardless of
> frequency/band - except under VSWR conditions based on settings.
> c. Perhaps both the "Auto" and "Man" indicators would be on in
> order to indicate this mode on the KAT front panel.
> 3. When the KAT500 sees a transition from split on to split off then
> go into "normal" (non Split) mode.
>
> The main reason I am using the tuner is because of a compromise
> antenna. If the antenna was flat enough across the band I wouldn't
> even engage it. In my specific situation there is also at KPA500
> connected, so the way that the
> KAT500 works today will result in the KAT inhibiting the KPA while it
> retunes/recalls. Although fast, I suspect that the amp is not engaged
> initially when I send (speak) my call sign in the pile. On very rare
> occasions there is also a KPA VSWR Fault. While probably not an
> issue, the amount of relay chatter in very short period of time
> between fast RX/TX/RX transitions is a bit unsettling.
>
> 73,
>
> Cliff K3LL
>
>
> -----Original Message-----
> From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of
> Jim Brown
> Sent: Sunday, November 15, 2015 10:04 AM
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] KAT500 Re-Tuning
>
>> On Sat,11/14/2015 8:37 PM, Byron Peebles wrote:
>> I will put the antenna analyzer on it tomorrow and make sure it's
>> still solid after all this wind.
>
> Other suggestions. First, put it on bypass and see what the SWR
> indication is. If it's reasonable, go to MAN mode, force a tuning (put
> K3 in TUN mode) and let it tune.
>
> Carefully check the entire coax path between K3 and the antenna. All
> connectors should be finger tight, then tighten with gas pliers.
>
> Any indication that the coax is wet? Moisture entering anywhere along
> the run will usually migrate all the way down to the lowest point.
> Open connectors to see if there's any moisture. A good way to test is
> to use a tissue or paper towel as a probe.
>
> If you have TDR capability, look at the feedline for any discontinuities.
> You should see connectors, the antenna, and any switching between the
> antenna and your test point. Most vector analyzers can do TDR. If you
> don't have one of them, ask around your ham neighbors to borrow one
> (and ask them to help you do the measurement).
>
> 73, Jim K9YC
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