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[Elecraft_K3] New from Elecraft: KPA1500 amplifier with built-in ATU, separate power supply

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john@kk9a.com

[Elecraft_K3] New from Elecraft: KPA1500 amplifier with built-in ATU, separate power supply

The KPA1500 tuner range is fine. If your antennas have >3:1 SWR you need
to do some work outside. It will help your signal much more than the amp.
Even when I operated the RTTY Roundup in January after an ice storm my
antennas were within this amplifiers SWR range.

John KK9A

from: Wes Stewartn7ws
Fri Apr 21 01:18:59 EDT 2017
]
Not enough full power tuner range.

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Wes Stewart-2

Re: [Elecraft_K3] New from Elecraft: KPA1500 amplifier with built-in ATU, separate power supply

A couple of points.

If you believe that an SWR of >3 necessarily degrades the efficiency of an
antenna, you are simply wrong.

If the "tuner" components have to be derated to this extent then perhaps it
should be called a line flattener rather than a tuner because a lot of guys are
still going to need a tuner.

On 4/21/2017 4:34 AM, [hidden email] wrote:

David Bunte

Re: [Elecraft_K3] New from Elecraft: KPA1500 amplifier with built-in ATU, separate power supply

Wes -

Excellent points. One of the locals has very fine antennas, but really
appreciates the fact that his PW-1 can make the SWR look a 'bit' better. At
my QTH, and TUNER, is absolutely necessary... but that is because I have
only one antenna, and it is usable without a tuner on only one band. The
internal tuners in most rigs can't handle it... the tuner in my K3, or my
KAT500, are perfect on most bands. But a 30' vertical is a HUGE challenge
for ANY tuner on 160... and many can't handle it on 80.

Dave - K9FN

On Fri, Apr 21, 2017 at 8:56 AM, Wes Stewart <[hidden email]> wrote:

> A couple of points.
>
> If you believe that an SWR of >3 necessarily degrades the efficiency of an
> antenna, you are simply wrong.
>
> If the "tuner" components have to be derated to this extent then perhaps
> it should be called a line flattener rather than a tuner because a lot of
> guys are still going to need a tuner.
>
>
>
>
> On 4/21/2017 4:34 AM, [hidden email] wrote:
>
>> The KPA1500 tuner range is fine. If your antennas have >3:1 SWR you need
>> to do some work outside. It will help your signal much more than the amp.
>> Even when I operated the RTTY Roundup in January after an ice storm my
>> antennas were within this amplifiers SWR range.
>>
>> John KK9A
>>
>> from: Wes Stewartn7ws
>> Fri Apr 21 01:18:59 EDT 2017
>> ]
>> Not enough full power tuner range.
>>
>>
> ______________________________________________________________
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briancom

Re: [Elecraft_K3] New from Elecraft: KPA1500 amplifier with built-in ATU, separate power supply

In reply to this post by john@kk9a.com

John,

Don't agree--unless there truly is something wrong with the antenna,
connections or feedline.

Does your 80 or 160M antenna cover the entire band with <3:1 SWR?

If fact, on those bands the extra loss due to SWR is negligible with
even 5:1 SWR's with usual coax. On 80M with a 5:1 SWR and 150' of RG8,
TLW computes an additional loss of about 0.5 dB. The 4.5 db gain due to
the extra power far outweighs the extra feedline loss. Factoring in
tuner loss doesn't change the conclusions. Even on 20M, the extra loss
for the above would be about 1.3 dB.

My experience with ice is much different. Adding ice to a 4 el quad,
the resonant frequency on 20M would shift 400 KHz (lower) giving 4:1
SWR's in the phone band. One could load it but run of the mill baluns
at the feedpoint would pop at legal limit!

73 de Brian/K3KO

On 4/21/2017 11:34 AM, [hidden email] wrote:

> The KPA1500 tuner range is fine. If your antennas have >3:1 SWR you need
> to do some work outside. It will help your signal much more than the amp.
> Even when I operated the RTTY Roundup in January after an ice storm my
> antennas were within this amplifiers SWR range.
>
> John KK9A
>
> from: Wes Stewartn7ws
> Fri Apr 21 01:18:59 EDT 2017
> ]
> Not enough full power tuner range.
>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
>

Jim Miller

Re: [Elecraft_K3] New from Elecraft: KPA1500 amplifier with built-in ATU, separate power supply

In reply to this post by Wes Stewart-2

Wes

Can you describe your affected antennas?

73

Jim ab3cv

On Apr 21, 2017, at 8:56 AM, Wes Stewart <[hidden email]> wrote:

A couple of points.

If you believe that an SWR of >3 necessarily degrades the efficiency of an antenna, you are simply wrong.

If the "tuner" components have to be derated to this extent then perhaps it should be called a line flattener rather than a tuner because a lot of guys are still going to need a tuner.

> On 4/21/2017 4:34 AM, [hidden email] wrote:
> The KPA1500 tuner range is fine. If your antennas have >3:1 SWR you need
> to do some work outside. It will help your signal much more than the amp.
> Even when I operated the RTTY Roundup in January after an ice storm my
> antennas were within this amplifiers SWR range.
>
> John KK9A
>
> from: Wes Stewartn7ws
> Fri Apr 21 01:18:59 EDT 2017
> ]
> Not enough full power tuner range.
>

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Alan Bloom

Re: [Elecraft_K3] New from Elecraft: KPA1500 amplifier with built-in ATU, separate power supply

With 1500W of power, if the SWR is greater than 3:1 you may be exceeding
the ratings of the feedline. For example, Belden 9914 is rated at a
maximum of 300 VRMS, which is 1800W with a 50-ohm feedline or only 600W
with a 3:1 SWR. At 30 MHz, RG-8/213 style coax is typically rated at
1500W with a 1:1 SWR.

It's true that you can do more than that with low-duty-factor modes like
CW and SSB, but if you are running much more than 3:1 SWR you may be in
danger of damaging the feedline.

Alan N1AL

On 04/21/2017 06:28 AM, Jim Miller wrote:

> Wes
>
> Can you describe your affected antennas?
>
> 73
>
> Jim ab3cv
>
> On Apr 21, 2017, at 8:56 AM, Wes Stewart <[hidden email]>
> wrote:
>
> A couple of points.
>
> If you believe that an SWR of >3 necessarily degrades the efficiency
> of an antenna, you are simply wrong.
>
> If the "tuner" components have to be derated to this extent then
> perhaps it should be called a line flattener rather than a tuner
> because a lot of guys are still going to need a tuner.
>
>
>
>> On 4/21/2017 4:34 AM, [hidden email] wrote: The KPA1500 tuner range
>> is fine. If your antennas have >3:1 SWR you need to do some work
>> outside. It will help your signal much more than the amp. Even when
>> I operated the RTTY Roundup in January after an ice storm my
>> antennas were within this amplifiers SWR range.
>>
>> John KK9A
>>

Wes Stewart-2

Re: [Elecraft_K3] New from Elecraft: KPA1500 amplifier with built-in ATU, separate power supply

In reply to this post by Jim Miller

I'm not necessarily defining a personal situation. But almost any 80 or 160
antenna will suffice as an example.

I am currently constructing a vertical for those bands. The model shows 2:1 on
160 at resonance and >3:1 just 60 KHz away and this is with considerable ground
loss. Less loss would equal lower BW. With quarter wave resonance on 80 at 3.6
MHz it exceeds 3:1 at 3.8 MHz and is nearly 7:1 at 4.0.

Transmission line loss is a non-issue with 7/8" Heliax.

On 4/21/2017 6:28 AM, Jim Miller wrote:

> Wes
>
> Can you describe your affected antennas?
>
> 73
>
> Jim ab3cv
>
> On Apr 21, 2017, at 8:56 AM, Wes Stewart <[hidden email]> wrote:
>
> A couple of points.
>
> If you believe that an SWR of >3 necessarily degrades the efficiency of an antenna, you are simply wrong.
>
> If the "tuner" components have to be derated to this extent then perhaps it should be called a line flattener rather than a tuner because a lot of guys are still going to need a tuner.
>
>
>
>> On 4/21/2017 4:34 AM, [hidden email] wrote:
>> The KPA1500 tuner range is fine. If your antennas have >3:1 SWR you need
>> to do some work outside. It will help your signal much more than the amp.
>> Even when I operated the RTTY Roundup in January after an ice storm my
>> antennas were within this amplifiers SWR range.
>>
>> John KK9A
>>
>> from: Wes Stewartn7ws
>> Fri Apr 21 01:18:59 EDT 2017
>> ]
>> Not enough full power tuner range.
>>

Clay Autery

Re: [Elecraft_K3] New from Elecraft: KPA1500 amplifier with built-in ATU, separate power supply

In reply to this post by Wes Stewart-2

Ease up for a minute.... Look at it my way. I KNOW I am gonna need an
external tuner with massive capability to do the same thing I am doing
now.... only one tuner on the commercial market will tune my 80m loop
at 1500W the way the K3s can.

I didn't WANT an onboard tuner... I consider the price point fair for
an amp only. It would cost me roughly that much to build one from a
true kit, boards, or schematic... (Looking forward to it).

Tuning full range, full-power, from 160-6m, from more than 3:1 gets
expensive, big, and heavy in a hurry....

MOST folks don't need/want a tuner like that, especially if it takes
more money out their pocket.

Consider the on-board tuner a bonus extra... and if so inclined send up
a prayer the FCC approval is rapidly forthcoming. :-)

73,

______________________
Clay Autery, KY5G

On 4/21/2017 7:56 AM, Wes Stewart wrote:

> A couple of points.
>
> If you believe that an SWR of >3 necessarily degrades the efficiency
> of an antenna, you are simply wrong.
>
> If the "tuner" components have to be derated to this extent then
> perhaps it should be called a line flattener rather than a tuner
> because a lot of guys are still going to need a tuner.
>
>
>
> On 4/21/2017 4:34 AM, [hidden email] wrote:
>> The KPA1500 tuner range is fine. If your antennas have >3:1 SWR you need
>> to do some work outside. It will help your signal much more than the
>> amp.
>> Even when I operated the RTTY Roundup in January after an ice storm my
>> antennas were within this amplifiers SWR range.
>>
>> John KK9A
>>
>> from: Wes Stewartn7ws
>> Fri Apr 21 01:18:59 EDT 2017
>> ]
>> Not enough full power tuner range.

Bill Breeden

Re: [Elecraft_K3] New from Elecraft: KPA1500 amplifier with built-in ATU, separate power supply

In reply to this post by Alan Bloom

An excellent point missed by many of the desktop tuner and high feedline
SWR advocates who insist on using coax fed antennas. Typically, they
blame their failures on cheap coax.

73,

Bill - NA5DX

On 4/21/2017 11:32 AM, Alan Bloom wrote:

> With 1500W of power, if the SWR is greater than 3:1 you may be
> exceeding the ratings of the feedline. For example, Belden 9914 is
> rated at a maximum of 300 VRMS, which is 1800W with a 50-ohm feedline
> or only 600W with a 3:1 SWR. At 30 MHz, RG-8/213 style coax is
> typically rated at 1500W with a 1:1 SWR.
>
> It's true that you can do more than that with low-duty-factor modes
> like CW and SSB, but if you are running much more than 3:1 SWR you may
> be in danger of damaging the feedline.
>
> Alan N1AL
>
>
> On 04/21/2017 06:28 AM, Jim Miller wrote:
>> Wes
>>
>> Can you describe your affected antennas?
>>
>> 73
>>
>> Jim ab3cv
>>
>> On Apr 21, 2017, at 8:56 AM, Wes Stewart <[hidden email]>
>> wrote:
>>
>> A couple of points.
>>
>> If you believe that an SWR of >3 necessarily degrades the efficiency
>> of an antenna, you are simply wrong.
>>
>> If the "tuner" components have to be derated to this extent then
>> perhaps it should be called a line flattener rather than a tuner
>> because a lot of guys are still going to need a tuner.
>>
>>
>>
>>> On 4/21/2017 4:34 AM, [hidden email] wrote: The KPA1500 tuner range
>>> is fine. If your antennas have >3:1 SWR you need to do some work
>>> outside. It will help your signal much more than the amp. Even when
>>> I operated the RTTY Roundup in January after an ice storm my
>>> antennas were within this amplifiers SWR range.
>>>
>>> John KK9A
>>>
> ______________________________________________________________
> 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
> Message delivered to [hidden email]
>

Clay Autery

Re: [Elecraft_K3] New from Elecraft: KPA1500 amplifier with built-in ATU, separate power supply

In reply to this post by Alan Bloom

Excellent point.... I look forward to deploying more/better copper! :-)

______________________
Clay Autery, KY5G

On 4/21/2017 11:32 AM, Alan Bloom wrote: