KAT500 vs KAT3

[k5oai]

Question about the difference between my KAT3 and my KAT500 tuning.
Currently running 1.57 firmware (although I have seen this b4 on earlier
versions) This happens on numerous bands, but for now lets talk 30m

Running 100w out of the K3 and no amp.
Vertical antenna KAT500 in AUTO tune best SWR 1.6:1
even after a long tune and then another tap to try to find a lower swr
still 1.6:1 best swr (KAT500 set to 1.8:1 to cause a retune)

KAT3 with same vertical antenna best swr 1.0:1

I have 2 antennas, one vertical and one horizontal on all bands,
so I would prefer to use the KAT500 as it has all my antennas into it

but I would also like to run the lower swr
but that isn't possible unless I do some multiple button pushes
kat500 ant 1 to 2
kat3 to bypass
kat500 to auto
then reverse
kat500 to byp
kat3 to ATU
kat500 ant2 to 1
to get back to the other antenna using the kat3

or I have to make the kat3 retune everytime I switch vert to horz if I
use only the kat3 for both

the idea is to have a quick switch from horz to vert and back
this should be possible using either tuner
with the swr the same on them both

the vertical has a 1.5:1 with out the tuner
the question is why won't the kat500 tune the vertical to a 1.0:1
if the kat3 will tune the same antenna to 1.0:1

--
GB & 73
K5OAI
Sam Morgan
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[Cookie]

Sam, I will need to do a bit of guessing because you do not describe your antennas well enough for me to know the answer, but it sounds like you have your vertical tuned for 30 meters with a radiation resistance of about 35 ohms.  If you have some door knob capacitors connect one from the antenna to ground.  Use the smallest capacity unit you have and see if that does not drop the SWR some.  You can also connect an open ended piece of coax to the feed point and the braid to ground and use it as a capacitor.  Try increasing lengths until you get the SWR down enough to please you.  I would probably say that it was good enough at 1.6.  If you get out and nothing arcs it might be OK.  The SWR at the transmitter end of the COAX is not very important, it is the SWR at the antenna end that causes the loss.  You need to connect your SWR meter at the antenna to know what that is, but a 1.6 SWR will not hurt much unless you are using about 1000 feet of
 coax to feed it.
 
Willis 'Cookie' Cooke, TDXS DX Chairman
K5EWJ & Trustee N5BPS, USS Cavalla, USS Stewart


________________________________
 From: Sam Morgan <[hidden email]>
To: "[hidden email]" <[hidden email]>
Sent: Monday, February 24, 2014 8:50 PM
Subject: [Elecraft] KAT500 vs KAT3
 

Question about the difference between my KAT3 and my KAT500 tuning.
Currently running 1.57 firmware (although I have seen this b4 on earlier versions) This happens on numerous bands, but for now lets talk 30m

Running 100w out of the K3 and no amp.
Vertical antenna KAT500 in AUTO tune best SWR 1.6:1
even after a long tune and then another tap to try to find a lower swr still 1.6:1 best swr (KAT500 set to 1.8:1 to cause a retune)

KAT3 with same vertical antenna best swr 1.0:1

I have 2 antennas, one vertical and one horizontal on all bands,
so I would prefer to use the KAT500 as it has all my antennas into it

but I would also like to run the lower swr
but that isn't possible unless I do some multiple button pushes
kat500 ant 1 to 2
kat3 to bypass
kat500 to auto
then reverse
kat500 to byp
kat3 to ATU
kat500 ant2 to 1
to get back to the other antenna using the kat3

or I have to make the kat3 retune everytime I switch vert to horz if I use only the kat3 for both

the idea is to have a quick switch from horz to vert and back
this should be possible using either tuner
with the swr the same on them both

the vertical has a 1.5:1 with out the tuner
the question is why won't the kat500 tune the vertical to a 1.0:1
if the kat3 will tune the same antenna to 1.0:1

-- GB & 73
K5OAI
Sam Morgan
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Please help support this email list: http://www.qsl.net/donate.html
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[Ignacy]

Due to issues with Expert 2k-fa, I compared many SWR devices. SWR metering in K3 is not very accurate although it is good enough. Without KAT3 turned on, SWR in K3 may indicate 1.0 while LP100 shows 1.5, and vice versa. When if K3 indicates 1.0 it may be from 1.0 to 1.7. Additional problems are cause by bad cables and uncompensated switches. The most accurate measurements IMHO are with antenna analyzers.

So perhaps there is no problem.

One way of indirectly measuring whether the match is OK is to check the power at the antenna (at 100W) with either KAT3 or KAT500 while monitoring the supply current. Similar output power and supply currents mean no worries. At high real mismatch the current may higher or lower, with real high not too good.

Ignacy, NO9E

[Tim Heasman]

Hi,
I wish to ask for a firmware change that would keep the KPA500 un-keyed
until the tune button is released on the K3 after the KAT500 has
completed a tuning cycle.  I have the tuning power set to 15 W on the
K3, which ends up as 300 W out if I have forgotten to put the KPA500 to
standby before starting a tune cycle.
If there is a setting already available that I have missed that achieves
the same I apologise in advance.
73
Tim
gm4lmh
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