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KAT500 Antenna Selection?

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Jim AB3CV

KAT500 Antenna Selection?

I notice the KAT500 has three antenna ports. Is it programmable to
auto-select the port from band data?

73

jim ab3cv
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Oliver Dröse

Re: KAT500 Antenna Selection?

As per information given by Elecraft and the field testers: YES.

73, Olli - DH8BQA

----- Original Message -----
From: "Jim Miller" <[hidden email]>
To: "Elecraft Reflector" <[hidden email]>
Sent: Wednesday, October 10, 2012 2:53 PM
Subject: [Elecraft] KAT500 Antenna Selection?

>I notice the KAT500 has three antenna ports. Is it programmable to
> auto-select the port from band data?
>
> 73
>
> jim ab3cv
> ______________________________________________________________
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> 09.10.2012
>

Jim Brown-10

Re: KAT500 Antenna Selection?

In reply to this post by Jim AB3CV

On 10/10/2012 5:53 AM, Jim Miller wrote:
> I notice the KAT500 has three antenna ports. Is it programmable to
> auto-select the port from band data?

Yes. And it doesn't even NEED band data -- like the KPA500, it
auto-detects the transmiitted frequency, recalls settings for that
frequency, and switches between antennas if it has been programmed to do
so. I've been beta-testing one for about a month. The only connections
between my K3, KPA500, and KAT500 are coax and PTT, and they work
together flawlessly. When I do contesting, I use the K3 and KAT500 with
my 30 year old Ten Tec Titan tube amp at legal limit power. Works fine
that way too.

A band data connection allows the KAT500 to switch when you change bands
on the K3, before you transmit. That saves a few hundred msec. So far,
I've not seen the need for it.

73, Jim K9YC
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Joe Subich, W4TV-4

Re: KAT500 Antenna Selection?

> A band data connection allows the KAT500 to switch when you change
> bands on the K3, before you transmit. That saves a few hundred msec.
> So far, I've not seen the need for it.

A band data connection allows the KAT500 to switch *before* RF is
applied rather than hot switching *after* RF begins. I would be
very concerned about the service life of the relays when using RF
switching at high power - particularly in a "constant power mode"
like RTTY.

Most relays have significantly higher "carry" ratings than "switch"
ratings and will not survive repeated switching at full power.
While the KAT500 may be fast enough to switch during the "ramp up"
time at the start of a transmission, that is still pushing the
envelope - particularly if one is using it with a "legal limit
amplifier".

73,

... Joe, W4TV

On 10/10/2012 10:41 AM, Jim Brown wrote:

> On 10/10/2012 5:53 AM, Jim Miller wrote:
>> I notice the KAT500 has three antenna ports. Is it programmable to
>> auto-select the port from band data?
>
> Yes. And it doesn't even NEED band data -- like the KPA500, it
> auto-detects the transmiitted frequency, recalls settings for that
> frequency, and switches between antennas if it has been programmed to do
> so. I've been beta-testing one for about a month. The only connections
> between my K3, KPA500, and KAT500 are coax and PTT, and they work
> together flawlessly. When I do contesting, I use the K3 and KAT500 with
> my 30 year old Ten Tec Titan tube amp at legal limit power. Works fine
> that way too.
>
> A band data connection allows the KAT500 to switch when you change bands
> on the K3, before you transmit. That saves a few hundred msec. So far,
> I've not seen the need for it.
>
> 73, Jim K9YC
> ______________________________________________________________
> Elecraft mailing list
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Jim Brown-10

Re: KAT500 Antenna Selection?

On 10/10/2012 7:59 AM, Joe Subich, W4TV wrote:
> Most relays have significantly higher "carry" ratings than "switch"
> ratings and will not survive repeated switching at full power.
> While the KAT500 may be fast enough to switch during the "ramp up"
> time at the start of a transmission, that is still pushing the
> envelope - particularly if one is using it with a "legal limit
> amplifier".

This is prevented by the requirement that PTT be "looped through" the
KAT500. When the KAT500 is tuning (or switching), PTT to the amp is
interrupted. The only condition under which this does not work well is
with an amp like the Titan, whose 30 year old logic won't allow
interrupting PTT to stop TX because that would hot-switch the T/R relay.
When using that amp, I transmit a dit or two (or tap the mic) to let the
KAT detect frequency so that it can switch bands before I transmit "for
real."

73, Jim K9YC
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Joe Subich, W4TV-4

Re: KAT500 Antenna Selection?

> This is prevented by the requirement that PTT be "looped through" the
> KAT500. When the KAT500 is tuning (or switching), PTT to the amp is
> interrupted.

This only moves the hot switching from the KAT500 to the amplifier.

Whilst the KPA500 can handle hot switching due to its PIN diode T/R
system (we won't talk about the clicks that result) other amplifiers -
particularly those with vacuum relays on the output - will certainly
suffer a catastrophic failure (damaged relays and/or "flashover" due
to the transient no load condition) if asked to hot switch on a
regular basis.

73,

... Joe, W4TV

On 10/10/2012 11:33 AM, Jim Brown wrote:

> On 10/10/2012 7:59 AM, Joe Subich, W4TV wrote:
>> Most relays have significantly higher "carry" ratings than "switch"
>> ratings and will not survive repeated switching at full power.
>> While the KAT500 may be fast enough to switch during the "ramp up"
>> time at the start of a transmission, that is still pushing the
>> envelope - particularly if one is using it with a "legal limit
>> amplifier".
>
> This is prevented by the requirement that PTT be "looped through" the
> KAT500. When the KAT500 is tuning (or switching), PTT to the amp is
> interrupted. The only condition under which this does not work well is
> with an amp like the Titan, whose 30 year old logic won't allow
> interrupting PTT to stop TX because that would hot-switch the T/R relay.
> When using that amp, I transmit a dit or two (or tap the mic) to let the
> KAT detect frequency so that it can switch bands before I transmit "for
> real."
>
> 73, Jim K9YC
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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Gary Gregory

Re: KAT500 Antenna Selection?

In reply to this post by Oliver Dröse

*Ollie,

Correct.

I might add the advantage of using AUXBUS on the KAT500 (for me at least)
is on receive, changing bands to 'check' another band, there is no need to
Tx a DAH to effect a change from say ANT1 to ANT2 if that is the antenna
assigned to that band.

Without AUXBUS connected one has to TX some RF to cause an antenna change.

Convenience! (but as noted by Jim, not essential)

YMMV
*
On 10 October 2012 22:58, Oliver Dröse <[hidden email]> wrote:

> As per information given by Elecraft and the field testers: YES.
>
> 73, Olli - DH8BQA
>
>
> ----- Original Message -----
> From: "Jim Miller" <[hidden email]>
> To: "Elecraft Reflector" <[hidden email]>
> Sent: Wednesday, October 10, 2012 2:53 PM
> Subject: [Elecraft] KAT500 Antenna Selection?
>
>
> >I notice the KAT500 has three antenna ports. Is it programmable to
> > auto-select the port from band data?
> >
> > 73
> >
> > jim ab3cv
> > ______________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:[hidden email]
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> >
> >
> > -----
> > E-Mail ist virenfrei.
> > Von AVG uberpruft - www.avg.de
> > Version: 2012.0.2221 / Virendatenbank: 2441/5321 - Ausgabedatum:
> > 09.10.2012
> >
>
> ______________________________________________________________
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>

--
*Gary*
*Start the day off slow, then taper off.........*
K3 #679
KPA500FT #18
KAT500FT 007
P3 #1629
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Jim Brown-10

Re: KAT500 Antenna Selection?

In reply to this post by Joe Subich, W4TV-4

On 10/10/2012 12:15 PM, Joe Subich, W4TV wrote:
> This only moves the hot switching from the KAT500 to the amplifier.

Not if the operator isn't stupid. A smart operator will do as I have
described -- a short burst of RF to let the KAT determine operating
frequency and recall settings. And with an amp like the Titan, simply
put it in standby to let the KAT tune if needed.

73, Jim K9YC
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Joe Subich, W4TV-4

Re: KAT500 Antenna Selection?

> Not if the operator isn't stupid.

... or tired, not thinking clearly, in a hurry to work a "new one",
changing the SO2R radio while concentrating on the run rig, or in a
hurry to work a multiplier on a new band, etc. It only takes one
time to forget to "tune" the KAT500 - or have something happen to a
normally well behaved antenna - for the KAT500 delay RTTY to a legal
limit amp by 1/4 second so the vacuum relay switches at full power
and end up with heap of trouble.

I'm not saying the RF switching/tuning isn't fine in its place but I
would certainly want to minimize the chances of a failure by using
the band data. If it were my design, the pass through PTT would not
activate until the input PTT had cycled - that is if the KAT500 had
to take the amplifier off line to retune, the PTT would not activate
until the input PTT had cleared and been asserted again.

73,

... Joe, W4TV

On 10/10/2012 4:56 PM, Jim Brown wrote:

> On 10/10/2012 12:15 PM, Joe Subich, W4TV wrote:
>> This only moves the hot switching from the KAT500 to the amplifier.
>
> Not if the operator isn't stupid. A smart operator will do as I have
> described -- a short burst of RF to let the KAT determine operating
> frequency and recall settings. And with an amp like the Titan, simply
> put it in standby to let the KAT tune if needed.
>
> 73, Jim K9YC
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
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K2GN

Re: KAT500 Antenna Selection?

In my opinion, antenna switching should either fully automatic or fully
manual.
I've had both, plus a mix. I've never had a problem when it fully one way
or the other.
But for various reasons as stated in Joe's, it created problems, popped
diodes, what have you. The K3/KAT500/KPA500 can work either way.
DON'T mix the methods!! You'll surely be saying "OOPS"(Or worst) sometime
in the future.
That "OOPS" can be expensive!!!
Larry/K2GN - http://k2gn.com

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Joe Subich, W4TV
Sent: Wednesday, October 10, 2012 5:14 PM
To: [hidden email]
Subject: Re: [Elecraft] KAT500 Antenna Selection?

> Not if the operator isn't stupid.

... or tired, not thinking clearly, in a hurry to work a "new one",
changing the SO2R radio while concentrating on the run rig, or in a hurry to
work a multiplier on a new band, etc. It only takes one time to forget to
"tune" the KAT500 - or have something happen to a normally well behaved
antenna - for the KAT500 delay RTTY to a legal limit amp by 1/4 second so
the vacuum relay switches at full power and end up with heap of trouble.

I'm not saying the RF switching/tuning isn't fine in its place but I would
certainly want to minimize the chances of a failure by using the band data.
If it were my design, the pass through PTT would not activate until the
input PTT had cycled - that is if the KAT500 had to take the amplifier off
line to retune, the PTT would not activate until the input PTT had cleared
and been asserted again.

73,

... Joe, W4TV

On 10/10/2012 4:56 PM, Jim Brown wrote:

> On 10/10/2012 12:15 PM, Joe Subich, W4TV wrote:
>> This only moves the hot switching from the KAT500 to the amplifier.
>
> Not if the operator isn't stupid. A smart operator will do as I have
> described -- a short burst of RF to let the KAT determine operating
> frequency and recall settings. And with an amp like the Titan, simply
> put it in standby to let the KAT tune if needed.
>
> 73, Jim K9YC
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net Please help support this email
> list: http://www.qsl.net/donate.html
>

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