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KAT500 SWR LED Doesn't Light with 1.0/1 SWR

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wmbrian

KAT500 SWR LED Doesn't Light with 1.0/1 SWR

I recently added the KAT500 and KPA500 to my K3 station.

I have noticed that when the SWR (after tuning) as displayed on the KPA500
is 1.0/1 (or occasionally 1.1/1) no SWR LED lights up on the KAT500. (The
green 1.0/1 SWR LED on the KPA500 does light up.)

I have assumed that the 1.2/1 KAT500 SWR LED does not light up is because 1)
the KAT500 threshold for the first SWR LED is 1.2/1 and 2) because no
tuning action has taken place in these circumstances (due to memorized
KAT500 tuning configuration). However, I noticed at the bottom of page 49
of Fred Cady's book on the KAT500 and the KPA500 it says "VSWR is displayed
even when the tuner is bypasssed". So, I'm confused. Does no SWR LED light
when the SWR is 1.0/1 (or very close to it) because the SWR is below 1.2/1?

Thanks,

Brian, K8GRR

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Bob McGraw - K4TAX

Re: KAT500 SWR LED Doesn't Light with 1.0/1 SWR

Yes I have that combination, KPA500 / KAT500. Over the years I've learned that a VSWR of 1.5:1 or less means little to nothing. Oh it's "comforting" to operate all the time with a 1.1:1 SWR but just accurate is that indication? And the fact the two devices show different values lends credence to " just how accurate is that indication". Plus many diode detection methods are least accurate at lower levels.

Conclusion: find something more interesting to worry about.

Bob, K4TAX

Sent from my iPhone

> On Apr 6, 2019, at 1:01 PM, wmbrian <[hidden email]> wrote:
>
> I recently added the KAT500 and KPA500 to my K3 station.
>
> I have noticed that when the SWR (after tuning) as displayed on the KPA500
> is 1.0/1 (or occasionally 1.1/1) no SWR LED lights up on the KAT500. (The
> green 1.0/1 SWR LED on the KPA500 does light up.)
>
> I have assumed that the 1.2/1 KAT500 SWR LED does not light up is because 1)
> the KAT500 threshold for the first SWR LED is 1.2/1 and 2) because no
> tuning action has taken place in these circumstances (due to memorized
> KAT500 tuning configuration). However, I noticed at the bottom of page 49
> of Fred Cady's book on the KAT500 and the KPA500 it says "VSWR is displayed
> even when the tuner is bypasssed". So, I'm confused. Does no SWR LED light
> when the SWR is 1.0/1 (or very close to it) because the SWR is below 1.2/1?
>
> Thanks,
>
> Brian, K8GRR
>
>
>
> --
> Sent from: http://elecraft.365791.n2.nabble.com/
> ______________________________________________________________
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Bill K9YEQ

Re: KAT500 SWR LED Doesn't Light with 1.0/1 SWR

In reply to this post by wmbrian

Does the power output LEDs give a reading? If they do and you show no reflected that should be ok. If you have a bride after that it may show no lite either. You can always bypass the KPA's and find a frequency where you see 2:1 then turn the KPA's back on and see if that gives a reading. If not, suggest you call tech support.

72 & 73,
Bill
K9YEQ
FT'er for K2, KX1, KX3, KXPA100, KAT500, W2, etc.

-----Original Message-----
From: [hidden email] <[hidden email]> On Behalf Of wmbrian
Sent: Saturday, April 6, 2019 1:02 PM
To: [hidden email]
Subject: [Elecraft] KAT500 SWR LED Doesn't Light with 1.0/1 SWR

I recently added the KAT500 and KPA500 to my K3 station.

I have noticed that when the SWR (after tuning) as displayed on the KPA500 is 1.0/1 (or occasionally 1.1/1) no SWR LED lights up on the KAT500. (The green 1.0/1 SWR LED on the KPA500 does light up.)

I have assumed that the 1.2/1 KAT500 SWR LED does not light up is because 1) the KAT500 threshold for the first SWR LED is 1.2/1 and 2) because no tuning action has taken place in these circumstances (due to memorized
KAT500 tuning configuration). However, I noticed at the bottom of page 49 of Fred Cady's book on the KAT500 and the KPA500 it says "VSWR is displayed even when the tuner is bypasssed". So, I'm confused. Does no SWR LED light when the SWR is 1.0/1 (or very close to it) because the SWR is below 1.2/1?

Thanks,

Brian, K8GRR

--
Sent from: http://elecraft.365791.n2.nabble.com/
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Bob McGraw - K4TAX

Re: KAT500 SWR LED Doesn't Light with 1.0/1 SWR

The SWR LED scaling on the KPA500 is different than the scaling on the KAT500. Yet the KPA500 does have a numerical readout......if one wishes to split hairs. 1.0, 1.1, 1.2, 1.3 and etc.

With LED type displays, there is always a "transition" point from one value / LED to the next. It could be at 1.4, or 1.5 or 1.6. Thus a value of 1.4 on one device could be 1.6 on another.

Bob, K4TAX

Sent from my iPhone

> On Apr 6, 2019, at 3:13 PM, Bill Johnson <[hidden email]> wrote:
>
> Does the power output LEDs give a reading? If they do and you show no reflected that should be ok. If you have a bride after that it may show no lite either. You can always bypass the KPA's and find a frequency where you see 2:1 then turn the KPA's back on and see if that gives a reading. If not, suggest you call tech support.
>
> 72 & 73,
> Bill
> K9YEQ
> FT'er for K2, KX1, KX3, KXPA100, KAT500, W2, etc.
>
> -----Original Message-----
> From: [hidden email] <[hidden email]> On Behalf Of wmbrian
> Sent: Saturday, April 6, 2019 1:02 PM
> To: [hidden email]
> Subject: [Elecraft] KAT500 SWR LED Doesn't Light with 1.0/1 SWR
>
> I recently added the KAT500 and KPA500 to my K3 station.
>
> I have noticed that when the SWR (after tuning) as displayed on the KPA500 is 1.0/1 (or occasionally 1.1/1) no SWR LED lights up on the KAT500. (The green 1.0/1 SWR LED on the KPA500 does light up.)
>
> I have assumed that the 1.2/1 KAT500 SWR LED does not light up is because 1) the KAT500 threshold for the first SWR LED is 1.2/1 and 2) because no tuning action has taken place in these circumstances (due to memorized
> KAT500 tuning configuration). However, I noticed at the bottom of page 49 of Fred Cady's book on the KAT500 and the KPA500 it says "VSWR is displayed even when the tuner is bypasssed". So, I'm confused. Does no SWR LED light when the SWR is 1.0/1 (or very close to it) because the SWR is below 1.2/1?
>
> Thanks,
>
> Brian, K8GRR
>
>
>
> --
> Sent from: http://elecraft.365791.n2.nabble.com/
> ______________________________________________________________
> 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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> Please help support this email list: http://www.qsl.net/donate.html
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Bill K9YEQ

Re: KAT500 SWR LED Doesn't Light with 1.0/1 SWR

Bob, thanks for input, but I understand the issue as to not get a reading on the SWR display of the KTA500 and the concern is there may be something amiss. Thus my suggestion to be sure the SWR LED is working and to figure it out, I suggested a simple method to make sure the LED on the SWR indicator can register/is working.

73,
Bill
K9YEQ

https://wrj-tech.com/

-----Original Message-----
From: Bob McGraw K4TAX <[hidden email]>
Sent: Saturday, April 6, 2019 4:04 PM
To: Bill Johnson <[hidden email]>
Cc: wmbrian <[hidden email]>; [hidden email]
Subject: Re: [Elecraft] KAT500 SWR LED Doesn't Light with 1.0/1 SWR

The SWR LED scaling on the KPA500 is different than the scaling on the KAT500. Yet the KPA500 does have a numerical readout......if one wishes to split hairs. 1.0, 1.1, 1.2, 1.3 and etc.

With LED type displays, there is always a "transition" point from one value / LED to the next. It could be at 1.4, or 1.5 or 1.6. Thus a value of 1.4 on one device could be 1.6 on another.

Bob, K4TAX

Sent from my iPhone

> On Apr 6, 2019, at 3:13 PM, Bill Johnson <[hidden email]> wrote:
>
> Does the power output LEDs give a reading? If they do and you show no reflected that should be ok. If you have a bride after that it may show no lite either. You can always bypass the KPA's and find a frequency where you see 2:1 then turn the KPA's back on and see if that gives a reading. If not, suggest you call tech support.
>
> 72 & 73,
> Bill
> K9YEQ
> FT'er for K2, KX1, KX3, KXPA100, KAT500, W2, etc.
>
> -----Original Message-----
> From: [hidden email]
> <[hidden email]> On Behalf Of wmbrian
> Sent: Saturday, April 6, 2019 1:02 PM
> To: [hidden email]
> Subject: [Elecraft] KAT500 SWR LED Doesn't Light with 1.0/1 SWR
>
> I recently added the KAT500 and KPA500 to my K3 station.
>
> I have noticed that when the SWR (after tuning) as displayed on the
> KPA500 is 1.0/1 (or occasionally 1.1/1) no SWR LED lights up on the
> KAT500. (The green 1.0/1 SWR LED on the KPA500 does light up.)
>
> I have assumed that the 1.2/1 KAT500 SWR LED does not light up is
> because 1) the KAT500 threshold for the first SWR LED is 1.2/1 and 2)
> because no tuning action has taken place in these circumstances (due
> to memorized
> KAT500 tuning configuration). However, I noticed at the bottom of page 49 of Fred Cady's book on the KAT500 and the KPA500 it says "VSWR is displayed even when the tuner is bypasssed". So, I'm confused. Does no SWR LED light when the SWR is 1.0/1 (or very close to it) because the SWR is below 1.2/1?
>
> Thanks,
>
> Brian, K8GRR
>
>
>
> --
> Sent from: http://elecraft.365791.n2.nabble.com/
> ______________________________________________________________
> 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
> ______________________________________________________________
> 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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> list: http://www.qsl.net/donate.html
>

Dick Dievendorff-4

Re: KAT500 SWR LED Doesn't Light with 1.0/1 SWR

In reply to this post by wmbrian

Brian:

Your KAT500 low order SWR LED, labeled "1.2", is illuminated when there is a
little bit of forward power and an SWR of 1.2:1 or higher is computed. If
the SWR is under 1.2:1, then no KAT500 SWR LEDs are illuminated. Even 500
watts of RF with little or no reflected power shouldn't light any KAT500 SWR
LEDs. The KPA500 (and KPA1500) have an SWR bar LED for 1.0. The KAT500's
first SWR LED is 1.2.

Fred's book is correct; your KAT500 performs an SWR calculation whether or
not the ATU is bypassed. That result can be displayed with the KAT500
Utility Operate page, or any other program that can send a command to the
KAT500 to read its SWR. If SWR is 1.2:1 or higher, then it's also displayed
on KAT500 SWR LEDs.

73 de Dick, K6KR

-----Original Message-----
From: [hidden email] <[hidden email]> On
Behalf Of wmbrian
Sent: Saturday, April 6, 2019 11:02
To: [hidden email]
Subject: [Elecraft] KAT500 SWR LED Doesn't Light with 1.0/1 SWR

I recently added the KAT500 and KPA500 to my K3 station.

I have noticed that when the SWR (after tuning) as displayed on the KPA500
is 1.0/1 (or occasionally 1.1/1) no SWR LED lights up on the KAT500. (The
green 1.0/1 SWR LED on the KPA500 does light up.)

I have assumed that the 1.2/1 KAT500 SWR LED does not light up is because 1)
the KAT500 threshold for the first SWR LED is 1.2/1 and 2) because no
tuning action has taken place in these circumstances (due to memorized
KAT500 tuning configuration). However, I noticed at the bottom of page 49
of Fred Cady's book on the KAT500 and the KPA500 it says "VSWR is displayed
even when the tuner is bypasssed". So, I'm confused. Does no SWR LED light
when the SWR is 1.0/1 (or very close to it) because the SWR is below 1.2/1?

Thanks,

Brian, K8GRR

--
Sent from: http://elecraft.365791.n2.nabble.com/
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Bill K9YEQ

Re: KAT500 SWR LED Doesn't Light with 1.0/1 SWR

Dick, thank you for jumping in. Has been a long time since I used the KAT500 now that KPA1500 is in the shack!

72 & 73,
Bill
K9YEQ
FT'er for K2, KX1, KX3, KXPA100, KAT500, W2, etc.

-----Original Message-----
From: [hidden email] <[hidden email]> On Behalf Of [hidden email]
Sent: Saturday, April 6, 2019 4:36 PM
To: 'wmbrian' <[hidden email]>; [hidden email]
Subject: Re: [Elecraft] KAT500 SWR LED Doesn't Light with 1.0/1 SWR

Brian:

Your KAT500 low order SWR LED, labeled "1.2", is illuminated when there is a little bit of forward power and an SWR of 1.2:1 or higher is computed. If the SWR is under 1.2:1, then no KAT500 SWR LEDs are illuminated. Even 500 watts of RF with little or no reflected power shouldn't light any KAT500 SWR LEDs. The KPA500 (and KPA1500) have an SWR bar LED for 1.0. The KAT500's first SWR LED is 1.2.

Fred's book is correct; your KAT500 performs an SWR calculation whether or not the ATU is bypassed. That result can be displayed with the KAT500 Utility Operate page, or any other program that can send a command to the
KAT500 to read its SWR. If SWR is 1.2:1 or higher, then it's also displayed on KAT500 SWR LEDs.

73 de Dick, K6KR

-----Original Message-----
From: [hidden email] <[hidden email]> On Behalf Of wmbrian
Sent: Saturday, April 6, 2019 11:02
To: [hidden email]
Subject: [Elecraft] KAT500 SWR LED Doesn't Light with 1.0/1 SWR

I recently added the KAT500 and KPA500 to my K3 station.

I have noticed that when the SWR (after tuning) as displayed on the KPA500 is 1.0/1 (or occasionally 1.1/1) no SWR LED lights up on the KAT500. (The green 1.0/1 SWR LED on the KPA500 does light up.)

I have assumed that the 1.2/1 KAT500 SWR LED does not light up is because 1) the KAT500 threshold for the first SWR LED is 1.2/1 and 2) because no tuning action has taken place in these circumstances (due to memorized
KAT500 tuning configuration). However, I noticed at the bottom of page 49 of Fred Cady's book on the KAT500 and the KPA500 it says "VSWR is displayed even when the tuner is bypasssed". So, I'm confused. Does no SWR LED light when the SWR is 1.0/1 (or very close to it) because the SWR is below 1.2/1?

Thanks,

Brian, K8GRR

--
Sent from: http://elecraft.365791.n2.nabble.com/
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ANDY DURBIN

KAT500 SWR LED Doesn't Light with 1.0/1 SWR

In reply to this post by wmbrian

"I have noticed that when the SWR (after tuning) as displayed on the KPA500
is 1.0/1 (or occasionally 1.1/1) no SWR LED lights up on the KAT500. (The
green 1.0/1 SWR LED on the KPA500 does light up.)"

That's normal. Why would you expect a 1.2 SWR LED to be lit when the SWR value is less than 1.2?

The range of the KPA500 LED SWR display is much greater that the range of the KAT500 LED SWR display. Also, neither of them will give a useful reading at low power levels. I suggest the LP-100A if you really want to know the load presented by your antenna system. It will give useful complex load information with power levels between 1 watt and legal limit.

The fact that the two LED SWR meters have different ranges, and different step points, may be by design. If the LED meters were identical people would perhaps expect them to always display the same value.

Don't forget that SWR is a poor indicator of antenna system load and the KPA500 really dislikes low R loads even if the SWR is less than 1.5:1.

73,
Andy. k3wyc
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Don Wilhelm

Re: KAT500 SWR LED Doesn't Light with 1.0/1 SWR

In reply to this post by Bob McGraw - K4TAX

All,

To amplify Bob's comments ---

That is one of the situations with digital displays Vs. analog.
An analog display might show your an SWR of 1.55 (if you can interpolate
the needle position) while the digital display resolution will show you
either a 1.5 or a 1.6 indication - there is no way to show an in-between
reading on a digital display.

73,
Don W3FPR

On 4/6/2019 5:04 PM, Bob McGraw K4TAX wrote:
> The SWR LED scaling on the KPA500 is different than the scaling on the KAT500. Yet the KPA500 does have a numerical readout......if one wishes to split hairs. 1.0, 1.1, 1.2, 1.3 and etc.
>
> With LED type displays, there is always a "transition" point from one value / LED to the next. It could be at 1.4, or 1.5 or 1.6. Thus a value of 1.4 on one device could be 1.6 on another.
>
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