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kpa800 question

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David Toepfer

kpa800 question

Is it too early to start asking questions about this?

I am wondering, will the KPA800 have to be closely tied to the K2 like the
KPA100 is, or will I be able to use it with other gear as well and with less
than 50-100W in?

I ask because I was considering the idea foregoing the purchase of a KPA100
this year and just waiting for a KPA800 to use to kick the K2 5-10W in up to
100W, but also to use with other gear to kick them up to 800W. I would buy one
if I can use it this way, but don't have as much use for one if it can not be.

Also, will there be a KAT800? :-)

dt
.

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Steve-292

RE: kpa800 question

The amp I saw Friday at the FDIM hotel was an independent unit. While the
specific question did not arrise during Q&A with Wayne & Eric, it would be
difficult to imagine a design of this class *requiring* a K2 to drive it. I
did not note any special control cable from the K2/100 to the amp.
73,
Steve
aa8af

> -----Original Message-----
>
> Is it too early to start asking questions about this?
>
> I am wondering, will the KPA800 have to be closely tied to
> the K2 like the KPA100 is, or will I be able to use it with
> other gear as well and with less than 50-100W in?
>
> I ask because I was considering the idea foregoing the
> purchase of a KPA100 this year and just waiting for a KPA800
> to use to kick the K2 5-10W in up to 100W, but also to use
> with other gear to kick them up to 800W. I would buy one if
> I can use it this way, but don't have as much use for one if
> it can not be.
>
> Also, will there be a KAT800? :-)
>
> dt

Jeff Stai WK6I

Re: kpa800 question

In reply to this post by David Toepfer

At 05:42 PM 5/24/2005, David Toepfer wrote:
>Is it too early to start asking questions about this?

possibly, so the following is opinion based on what I have seen...

>I am wondering, will the KPA800 have to be closely tied to the K2 like the
>KPA100 is, or will I be able to use it with other gear as well and with less
>than 50-100W in?

the KPA800 will work with any rig. Two rigs actually. The only necessary connection is RF and a Key Enable. You can also give it band data, though it will auto sense the frequency.

I can't say how it will behave with low drive.

>I ask because I was considering the idea foregoing the purchase of a KPA100
>this year and just waiting for a KPA800 to use to kick the K2 5-10W in up to
>100W, but also to use with other gear to kick them up to 800W. I would buy one
>if I can use it this way, but don't have as much use for one if it can not be.

chances are, someone will try it when they get one and report here...

>Also, will there be a KAT800? :-)

If I understood correctly (and I'm pretty sure I did) the tuner is built into the amp, and can handle at least 3:1 mismatch.

hope this helps - jeff wk6i

--
Jeff Stai [hidden email]
Twisted Oak Winery http://www.twistedoak.com/
Rocketry Org. of CA http://www.rocstock.org/
Amateur Radio WK6I ~ Calaveras County, CA
40th Annual California QSO Party! ~ Oct 1-2, 2005 ~ http://www.cqp.org/

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k0wa@swbell.net

Re: kpa800 question

In reply to this post by David Toepfer

What I found is that the amp needs to have around 50
watts to be driven to full output. There is a rule
with the FCC that requires higher drive for full
output so other types (CB types) can't put in 5-watts
and get out 800 watts. So, the by rule the amp is
limited in drive...I think it is 13 db, but I am not
sure.

The amp is a stand alone and can be used with any rig.

It is 80% the size of an Alpha

It has a built in antenna tunner. PIN Diode switching
and a switching power supply.

Fully metered too.

Lee - K0WA

Common sense is in short supply - get some and use it.
If you can't find any common sense, ask for help from
somebody that has some common sense. - Lee Buller
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N2TK

RE: kpa800 question

It has band pass filters in the output - similar concept to the K2/100. I
believe Eric said it is Pi-L. There is no antenna tuner in the amp.
N2TK, Tony

-----Original Message-----
From: elecraft-bounces+tony.kaz=[hidden email]
[mailto:elecraft-bounces+tony.kaz=[hidden email]]On Behalf Of
Lee Buller
Sent: Tuesday, May 24, 2005 11:19 PM
To: David Toepfer; Elecraft Reflector
Subject: Re: [Elecraft] kpa800 question

What I found is that the amp needs to have around 50
watts to be driven to full output. There is a rule
with the FCC that requires higher drive for full
output so other types (CB types) can't put in 5-watts
and get out 800 watts. So, the by rule the amp is
limited in drive...I think it is 13 db, but I am not
sure.

The amp is a stand alone and can be used with any rig.

It is 80% the size of an Alpha

It has a built in antenna tunner. PIN Diode switching
and a switching power supply.

Fully metered too.

Lee - K0WA

Common sense is in short supply - get some and use it.
If you can't find any common sense, ask for help from
somebody that has some common sense. - Lee Buller
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Bob Henderson

Re: kpa800 question

"N2TK, Tony" said

> There is no antenna tuner in the amp.

Tony

I believe you are mistaken. I spent some time talking to Eric at Dayton and
also to Dick K4XU, the semiconductor applications engineer involved in the
design. They left me with a firm impression the amp has an auto-tune atu
built in, together with a switch mode psu. The 800W version is to be
available in part constructed kit form and also fully built. Timescales
appear to Fall 05. A full 1500W is also planned and availability will lag
the 800W version by a few months. The 1.5kW amp will have an external psu
on which the amp can stand. Overall size of the amp is approx 80% the size
of an Alpha 87A, with which it shares similar styling.

The 800W version is also planned to be field upgradable to the 1.5 kW spec.

Bob, 5B4AGN, P3F

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Bill Coleman-2

Re: kpa800 question

In reply to this post by k0wa@swbell.net

On May 24, 2005, at 11:19 PM, Lee Buller wrote:

> It is 80% the size of an Alpha

So, is that 80% of the external dimensions, or 80% of the volume?

Is this the size of an EC2, or considerably larger?

Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901

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David Toepfer

Re: kpa800 question

In reply to this post by David Toepfer

Oh, no, I was not hoping for full power out with 5W in. I was just wondering
if I could expect up to 100W out with 5M in (assuming a max 13dB gain), or is
it somehow limited or inefficient with such low drive power. I would just like
to have only one amp I could use to bring something like a K1 or K2 up to
50-100W and also use to bring a a 40W AM/CW rig up to 800W.

I guess I may just have to wait until the web site announces official specs and
ask when I see them.

dt
.

--- Lee Buller <[hidden email]> wrote:

>
> What I found is that the amp needs to have around 50
> watts to be driven to full output. There is a rule
> with the FCC that requires higher drive for full
> output so other types (CB types) can't put in 5-watts
> and get out 800 watts. So, the by rule the amp is
> limited in drive...I think it is 13 db, but I am not
> sure.
>
> The amp is a stand alone and can be used with any rig.
>
> It is 80% the size of an Alpha
>
> It has a built in antenna tunner. PIN Diode switching
> and a switching power supply.
>
> Fully metered too.
>
> Lee - K0WA
>
>
> Common sense is in short supply - get some and use it.
> If you can't find any common sense, ask for help from
> somebody that has some common sense. - Lee Buller
>

Nigel A. Gunn G8IFF/KC8NHF

Re: kpa800 question

Buy a KPA800 AND a KPA1500 and get full legal output for 5W drive.
Sounds ideal.

David Toepfer wrote:

>Oh, no, I was not hoping for full power out with 5W in. I was just wondering
>if I could expect up to 100W out with 5M in (assuming a max 13dB gain), or is
>it somehow limited or inefficient with such low drive power. I would just like
>to have only one amp I could use to bring something like a K1 or K2 up to
>50-100W and also use to bring a a 40W AM/CW rig up to 800W.
>
>I guess I may just have to wait until the web site announces official specs and
>ask when I see them.
>
>dt
>
>

Mike Harris-9

Re: kpa800 question

In reply to this post by David Toepfer

G'day all,

All this talk about 800W amps is interesting, however, due to oil prices
the power company here has had to shove up the price per kWh to about 27c
US. I'll stick with more and better high level aluminium which sucks as
well as blows. Less potential TVI too.

Regards,

Mike VP8NO

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srife

RE: kpa800 question

In reply to this post by Steve-292

That was going to be my question...if it is controllable from the K2
like the KPA100 is. Sort of like the transverters, designed for the K2, but
can be used with other rigs.

Stan Rife
W5EWA
Houston, TX
K2 S/N 4216

-----Original Message-----
From: elecraft-bounces+srife=[hidden email]
[mailto:elecraft-bounces+srife=[hidden email]] On Behalf Of
Steve
Sent: Tuesday, May 24, 2005 9:44 PM
To: 'David Toepfer'
Cc: [hidden email]
Subject: RE: [Elecraft] kpa800 question

The amp I saw Friday at the FDIM hotel was an independent unit. While the
specific question did not arrise during Q&A with Wayne & Eric, it would be
difficult to imagine a design of this class *requiring* a K2 to drive it. I
did not note any special control cable from the K2/100 to the amp.
73,
Steve
aa8af

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David Toepfer

Re: kpa800 question

In reply to this post by David Toepfer

I agree, but, some of us have no room/permission for an antenna that is worth
anything, and have to make up for it somehow.

dt
.

--- Mike Harris <[hidden email]> wrote:

> G'day all,
>
> All this talk about 800W amps is interesting, however, due to oil prices
> the power company here has had to shove up the price per kWh to about 27c
> US. I'll stick with more and better high level aluminium which sucks as
> well as blows. Less potential TVI too.
>
> Regards,
>
> Mike VP8NO
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
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>
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>

EricJ-2

RE: kpa800 question

In reply to this post by Mike Harris-9

My electric bill came today and it worked out to 11.7 cents/kwh. I suppose I
could then afford to run a kw, but as you say, a bunch of aluminum up high
(TH7DX @ 65') works both ways. With a linear, you pay so that the guy at the
other end has an easier time of it!

It's not going to be on my Christmas List to Santa this year, but I think it
will be good for the Elecraft brand name, and that eventually helps us all.

Eric
KE6US

-----Original Message-----
From: elecraft-bounces+eric_csuf=[hidden email]
[mailto:elecraft-bounces+eric_csuf=[hidden email]] On Behalf Of
Mike Harris
Sent: Wednesday, May 25, 2005 3:35 PM
To: [hidden email]
Subject: Re: [Elecraft] kpa800 question

G'day all,

All this talk about 800W amps is interesting, however, due to oil prices the
power company here has had to shove up the price per kWh to about 27c US.
I'll stick with more and better high level aluminium which sucks as well as
blows. Less potential TVI too.

Regards,

Mike VP8NO

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johnny-52

Re: kpa800 question

Let us look at the matter in a different way. The skill required in the
construction a real QRO solid state power amplifer is different. KPA800
will be an entire different training for myself as a non-radio profession.

Cheers,

Johnny Siu VR2XMC
----- Original Message -----
From: "EricJ" <[hidden email]>
To: "'Mike Harris'" <[hidden email]>; <[hidden email]>
Sent: Thursday, May 26, 2005 9:03 AM
Subject: RE: [Elecraft] kpa800 question

> My electric bill came today and it worked out to 11.7 cents/kwh. I suppose
> I
> could then afford to run a kw, but as you say, a bunch of aluminum up high
> (TH7DX @ 65') works both ways. With a linear, you pay so that the guy at
> the
> other end has an easier time of it!
>
> It's not going to be on my Christmas List to Santa this year, but I think
> it
> will be good for the Elecraft brand name, and that eventually helps us
> all.
>
> Eric
> KE6US

Brian Mury-3

antenna suggestions? (was Re: kpa800 question)

In reply to this post by David Toepfer

On Wed, 2005-25-05 at 17:04 -0700, David Toepfer wrote:
> I agree, but, some of us have no room/permission for an antenna that is worth
> anything, and have to make up for it somehow.

You've got it good! Right now I've got no antenna at all.

I'm away from home for about 15 months, living in an 11x15 foot room.
It's basically the equivalent of a small hotel room. It's on the 3rd
floor and has a window, but no balcony. It's probably not a great idea
to string wire out the window (it's military barracks). I should be able
to get away with attaching stuff to the walls.

So - any antenna suggestions? Preferably something inexpensive and easy
to build as I have almost no tools here. Some ideas I've been thinking
about are a random wire (using the tuner), a homebrew buddipole, perhaps
a magnetic loop to stick by the window, or a shortened vertical.

The rig is a K2/100, and I do have a MFJ tuner if I need it.

All suggestions gratefully accepted!

--
73, Brian
VE7NGR
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EricJ-2

RE: kpa800 question

In reply to this post by johnny-52

Training for what? You're only going to do it once!

Eric
KE6US

-----Original Message-----
From: elecraft-bounces+eric_csuf=[hidden email]
[mailto:elecraft-bounces+eric_csuf=[hidden email]] On Behalf Of
JS
Sent: Wednesday, May 25, 2005 6:39 PM
To: [hidden email]
Subject: Re: [Elecraft] kpa800 question

Let us look at the matter in a different way. The skill required in the
construction a real QRO solid state power amplifer is different. KPA800
will be an entire different training for myself as a non-radio profession.

Cheers,

Johnny Siu VR2XMC
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johnny-52

Re: kpa800 question

The construction technique and tuning procedures would be different from K2.
It should be an interesting construction experience.

73

Johnny Siu VR2XMC
s/n 1146, 4165, 3837, 4255, 4597

----- Original Message -----
From: "EricJ" <[hidden email]>
To: "'JS'" <[hidden email]>; <[hidden email]>
Sent: Thursday, May 26, 2005 10:07 AM
Subject: RE: [Elecraft] kpa800 question

> Training for what? You're only going to do it once!
>
> Eric
> KE6US
>
> -----Original Message-----
> From: elecraft-bounces+eric_csuf=[hidden email]
> [mailto:elecraft-bounces+eric_csuf=[hidden email]] On Behalf
> Of
> JS
> Sent: Wednesday, May 25, 2005 6:39 PM
> To: [hidden email]
> Subject: Re: [Elecraft] kpa800 question
>
> Let us look at the matter in a different way. The skill required in the
> construction a real QRO solid state power amplifer is different. KPA800
> will be an entire different training for myself as a non-radio profession.
>
> Cheers,
>
> Johnny Siu VR2XMC
>

EricJ-2

RE: kpa800 question

Definitely. It should be fun. And when you let the smoke out, you REALLY let
the smoke out. Hi.

73, Johnny

Eric
KE6US

-----Original Message-----
From: JS [mailto:[hidden email]]
Sent: Wednesday, May 25, 2005 7:16 PM
To: EricJ; [hidden email]
Subject: Re: [Elecraft] kpa800 question

The construction technique and tuning procedures would be different from K2.

It should be an interesting construction experience.

73

Johnny Siu VR2XMC
s/n 1146, 4165, 3837, 4255, 4597

----- Original Message -----
From: "EricJ" <[hidden email]>
To: "'JS'" <[hidden email]>; <[hidden email]>
Sent: Thursday, May 26, 2005 10:07 AM
Subject: RE: [Elecraft] kpa800 question

Ron D'Eau Claire-2

RE: antenna suggestions? (was Re: kpa800 question)

In reply to this post by Brian Mury-3

Brian, VE7NGR, asked:

...Right now I've got no antenna at all.

I'm away from home for about 15 months, living in an 11x15 foot room. It's
basically the equivalent of a small hotel room. It's on the 3rd floor and
has a window, but no balcony. It's probably not a great idea to string wire
out the window (it's military barracks). I should be able to get away with
attaching stuff to the walls.

So - any antenna suggestions? Preferably something inexpensive and easy to
build as I have almost no tools here. Some ideas I've been thinking about
are a random wire (using the tuner), a homebrew buddipole, perhaps a
magnetic loop to stick by the window, or a shortened vertical.

The rig is a K2/100, and I do have a MFJ tuner if I need it.

All suggestions gratefully accepted!

---------------------------------------------

Are you by chance in a wooden barracks building such as I recall lo' these
many years ago? Or in one of those modern monoliths of military might made
from concrete and steel?

If wood, I'd suggest ignoring the building itself. It won't do the RF much
harm. I'd go for a balanced (or sorta balanced) situation. Run two wires up
the wall from the ATU to the ceiling. Make them about 2 or 3 inches apart.
That's your "balanced line". When you get to the ceiling (or rafters,
depending upon whether you have a "finished ceiling", the wires go opposite
directions around the room until the almost meet opposite the "feed line".
Keep them several inches apart at least and insulate those ends! (They'll be
very hot with RF and you don't want to promote excessive losses). Small bits
of plastic will do, or just use some plastic monofilament fishing line for
the last few inches to a push-pin holder. Staples, pushpins, whatever you
have handy are good for holding my wire. My favorite are push-pins with a
loop of antenna wire around each pin.

You can use the balun in your MFJ for "balanced feed" but it'll probably
work as well (or better!) if you simply hook one side of the feeder to the
tuner case and the other side to the single wire feed terminal (or the coax
center pin, which will take a banana plug FB).

Ignoring the balun might be better than trying for "balanced feed" because
under many conditions those baluns can be very, very lossy!

IF it's a concrete/steel building, that same system might work well too, but
the concrete/steel might show high losses too. I'd try to get outdoors with
the radiating half at least. Perhaps something out the window. Hang a wire
down toward the ground that you can pull up and stow when you're not
operating. Put a weight on the end so it'll hang straight and try not to
bonk the C.O. on the head with the thing. Run a wire along the floor for
your "ground". A 1/4 wave wire for each band is best. You can put 'em on the
wall or around the baseboard, etc.

Ron AC7AC

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Stuart Rohre

Re: antenna suggestions? (was Re: kpa800 question)

Brian,
With a window you could deploy a homemade version of the B&W window loaded
antenna. It was a whip as long as you dare, and a base loading coil, which
you can wind and tap for various bands. Put a counterpoise wire for say 33
feet on ground side of feedpoint at base of coil. Tap up on coil with coax
to find 5 0 ohm match. A jumper shorts out parts of coil for various bands.
If the whip is 6 feet you will find collapsible ones at some radio outlets.
72,
Stuart
K5KVH

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