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Re: KPA500 and KAT500 Ports

Posted by Joe Subich, W4TV-4 on Jul 14, 2011; 4:50am
URL: http://elecraft.85.s1.nabble.com/KPA500-and-KAT500-Ports-tp6574422p6581882.html



 > In either format I think that it should have not more than 2 inputs,
 > 3 unbalanced and one balanced output and that the tuner should be
 > capable of matching a 10:1 VSWR load. (As compared to 50 ohms)

There is a lot of lily gilding here ... the tuner, in either format
does not need more than two outputs following in the format established
in the K3.  One output can be either unbalanced (coax), balanced or
single wire.

It certainly does not require two inputs as it can't service more than
one RF generator (rig) at a time and would either follow a KPA-500 with
a single output or replace the KAT-3.

A 10:1 VSWR load rating is craziness - particularly for a 600W rated
tuner.  10:1 VSWR means 5KV/50A peak ratings ... something that would
handle 3:1 SWR at the W/VE "legal limit."  3:1 or 5:1 is far more
reasonable for a "high power" tuner ... and can handle the open wire
fed doublet or inverted L as long as the user avoids pathological
lengths of feedline (1/4 wave of open wire line) or antenna length
(full wave doublet or half wave inverted L).

> The desktop unit should be as small as possible but I personally
> don't think that 'P3 size' will be big enough due to the high
> voltages that can (and do) develop in the tuner, in a P3 sized case
> there would exist the real possibility of flashover with disastrous
> results for the tuner and / or amplifier / rig.

P3 size is entirely appropriate if the matching range is kept within
reason.  Elecraft have already discussed the P3 form factor.  Again,
multiple antenna outputs is complicated by a wide matching range -
the P3 format is entirely reasonable if antenna switching and matching
range are kept within reason.

> I also envisage that the remote unit will have to rely on RF sensing
> alone, due to the possible distances involved between it and the
> transceiver / amplifier unless some type of data bus capability is
> installed that is capable of operating over the long distances (10 to
> 100 metres or more) that is also compatible with the K2/K3/KRC2 etc.

There are several "high audio" communications protocols that would be
very suitable for multiplex operation over coax with the RF and DC
power.  Chip sets are readily available at reasonable prices and the
band splitting (high pass/low pass) filters are not unreasonable at
the 600 W level.  Even if multiplex operation is not desired, outdoor
rated CAT5/CAT6 cable is quite satisfactory for control to several
hundred meters with the appropriate drivers.

73,

    ... Joe, W4TV


On 7/13/2011 10:31 PM, Jeff Cochrane - VK4BOF wrote:

> Personally, I think that we need a reality check here people.
> Let's face it, what we 'want' and what we 'need' are two sometimes vastly different things.
> Wanting to be able to switch up to 18 antennas is so far outside the realms of sanity to try to implement in an antenna tuner it's ridiculous.
>
> Let's get back to basics, I am told that the KAT500 tuner will most likely be available in two formats, one a desktop unit and one a remote unit.
> In either format I think that it should have not more than 2 inputs, 3 unbalanced and one balanced output and that the tuner should be capable of matching a 10:1 VSWR load. (As compared to 50 ohms)
> Those are the basic requirements IMHO.
>
> Now, on to packaging.
> The desktop unit should be as small as possible but I personally don't think that 'P3 size' will be big enough due to the high voltages that can (and do) develop in the tuner, in a P3 sized case there would exist the real possibility of flashover with disastrous results for the tuner and / or amplifier / rig.
> I envisage something of similar size (for the desktop units at least) to a K3 if anything.
> This will give more than enough space for the tuner plus the associated switching needs to select the different antennae.
> The remote unit will no doubt be smaller due to not needing a capability of local human interaction and will probably have only one input.
> As well the remote unit will need waterproofing to IP65 or better.
>
> Functionality:
> I envisage that the desktop unit shall be not only able to select between the 2 rig inputs&  3 antenna outlets but can do so according to the band that the radio (I am assuming that an Elecraft K3 or least a K2 will be used with it.) is on and do so automagically via AUXBUS control.
> If the transceiver used is not an Elecraft rig (Shame on you!) then possibly the tuner should have some sort of RF sensing capabilities, ala KPA500.
>
> I also envisage that the remote unit will have to rely on RF sensing alone, due to the possible distances involved between it and the transceiver / amplifier unless some type of data bus capability is installed that is capable of operating over the long distances (10 to 100 metres or more) that is also compatible with the K2/K3/KRC2 etc.
> Failing that maybe a serial interface could be used but that would mean that level convertors and logic decoders would have to be used at either end, thereby complicating things even more. (And not to mention, adding extra cost to the units)
>
> Whatever the good folk at Elecraft come up with I don't mind betting that it's gunna be awesome, just like the rest of their gear! :)
>
> 73 de
>
> Jeff Cochrane - VK4BOF
> Elecraft K3 # 4257 + K144XV + KPA500 + PR6  = Fanbloodytasic performance!
>    ----- Original Message -----
>    From: Eric Swartz - WA6HHQ, Elecraft
>    To: Brendan Minish
>    Cc: [hidden email]
>    Sent: Thursday, July 14, 2011 10:01 AM
>    Subject: Re: [Elecraft] KPA500 and KAT500 Ports
>
>
>    Why not just use two KRC2s? They are complete and shipping. :-)
>
>    73, Eric
>
>    ---
>    www.elecraft.com
>
>
>    On 7/13/2011 4:22 PM, Brendan Minish wrote:
>    >  I think that 2 Antenna ports on the KAT500 is a good fit, after all 2
>    >  ports is what the K3 (+ATU) has so many of us have configured our
>    >  stations to work with this configuration
>    >
>    >  I would suggest however that there be an (optional?) module (s) for the
>    >  KAT500 that provides for sink or source outputs, one per band (plus a
>    >  few more?) that can be further configured via software to to clever
>    >  things (like selecting 2 different antennas for 80/75m, or multiple
>    >  bands on one antenna )
>    >  It would be even nicer if this was duplicated for the second antenna
>    >  output either in the same module or as a second user installable module.
>    >
>    >  These would be driven by the auxbus data that will presumably be fed to
>    >  the KANT500 and decoded by it's CPU anyway.
>    >  An input (per antenna port) that can be used to indicate to the KAT500
>    >  that the requested antenna is not available might also be a good idea so
>    >  that the KRC500 can then select the second choice on the other port
>    >  (complete with recalling the last used tunings for the secondary ) would
>    >  also be nice.
>    >
>    >  Think of this as the functionality of (2x ?) KRC2's built in and it
>    >  would make for superb versatility since the KRC500 could then be
>    >  configured to automate pretty much any external automatic antenna
>    >  switching arrangement.
>    >
>    >  I don't know if this is practical to fit into the box but it sure would
>    >  be nice.
>    >  The KRC2 may already form the basis for much of the required
>    >  circuitry/firmware.
>    >  The Sink/source outputs could be selected sink/source by internal jumper
>    >  and the output could be on DB15 or DIN connectors to minimise rear panel
>    >  real estate. (perhaps with pre-made breakout cable supplied )
>    >  Another option might be to have the 'Glue' internal to the KPA500 and
>    >  the Sink/source drivers in a 'dongle' to conserve internal space and
>    >  provide for easier breakout.
>    >
>    >  73
>    >  Brendan EI6IZ
>    >
>    >
>    >
>    >
>    >  On Tue, 2011-07-12 at 15:34 -0700, Eric Swartz - WA6HHQ, Elecraft wrote:
>    >>  Hi Gary,
>    >>
>    >>  Having 4-5 RG8 antenna cables, plus the input cable, hanging out the
>    >>  back of the desktop ATU is both likely to pull the ATU off the desk, and
>    >>  will easily not fit in the box size we are planning. It also adds a lot
>    >>  of complexity and cost to the basic ATU in order to accommodate more
>    >>  connections with the needed isolation etc. We certainly do not want to
>    >>  price the ATU out of the range of most hams, or make it too large.
>    >>
>    >>  Many of us use manual or automatic switches external to the amp / tuner
>    >>  to provide these functions.
>    >>
>    >>  A much better solution for those needing more than two auto-selected
>    >>  antennas is to use an external relay switch box, controlled by the
>    >>  radio. This has the advantage of getting the cables, clutter, and
>    >>  switching network off the desktop and either under the table or outside.
>    >>  There are certainly a number of external antenna switches out there that
>    >>  can do this, but if we offered something that was tightly integrated
>    >>  with the K3 (and KPA500/KAT500) as a product, what features would be
>    >>  desirable? (Number of antennas, rigs inputs, switching options etc.)
>    >>
>    >>  73, Eric WA6HHQ
>    >>
>    >>  ---
>    >>  www.elecraft.com
>    >>
>    >>
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