Discussion:
Barebone K2 Amplifier?
(too old to reply)
Fred (FL)
2006-12-07 23:25:44 UTC
Permalink
Are there any 50 or 100 watt external amplifiers,
that a barebone QRP K2 can drive? Is anyone
using one, for SSB and CW?

Itch'n to build nother ...........

Thanks,
Fred N3CSY
K2 54xx, 6/06



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Doug Person
2006-12-07 23:39:12 UTC
Permalink
Long ago Ten-Tec made a model 405 amplifier. It could take 5 watts in
and produce 50 watts out. There are also some Tokyo Highpower amps
around that people have bought directly from Japan. You could also
arrange to buy one directly from the company. They technically aren't
legal because the FCC has restrictions on input power, bands and gain to
(unsuccessfully) prevent CB operators from running more than 4 watts
output. Otherwise, there are plans and boards to build a 140 watt amp
that would be quite suitable. I also believe it is possible to make the
KPA100 an external amplifier. I've used a number of these and in my
book if you want 100 watts - buy the KPA100. I built one of the first
and it was a gem.

73, Doug -- K?DXV
Post by Fred (FL)
Are there any 50 or 100 watt external amplifiers,
that a barebone QRP K2 can drive? Is anyone
using one, for SSB and CW?
Itch'n to build nother ...........
Thanks,
Fred N3CSY
K2 54xx, 6/06
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Gregg R. Lengling
2006-12-07 23:41:10 UTC
Permalink
Why not build the KPA100 and put it in an EC2 to make it outboard??? You'll
really be happy!

-----Original Message-----
From: elecraft-***@mailman.qth.net
[mailto:elecraft-***@mailman.qth.net] On Behalf Of Fred (FL)
Sent: Thursday, December 07, 2006 4:23 PM
To: ***@mailman.qth.net
Subject: [Elecraft] Barebone K2 Amplifier?

Are there any 50 or 100 watt external amplifiers,
that a barebone QRP K2 can drive? Is anyone
using one, for SSB and CW?

Itch'n to build nother ...........

Thanks,
Fred N3CSY
K2 54xx, 6/06



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Bob Nielsen
2006-12-08 00:02:07 UTC
Permalink
Post by Fred (FL)
Are there any 50 or 100 watt external amplifiers,
that a barebone QRP K2 can drive? Is anyone
using one, for SSB and CW?
Itch'n to build nother ...........
Under the current FCC rules, an external amplifier cannot be driven
to its rated output win an input of less than 50 watts. Additionally
it cannot have more than 15 dB gain. Under the changes that take
effect on December 15, the 50 watt restriction is removed, although
the 15 dB gain limit is retained (don't ask me why).

The KPA-100 isn't subject to the 50 watt rule, because it is designed
to be integrated with the K2 as a single unit. It can be operated
separately (usually ? la <http://www.kk7p.com/k2kpa100.html> but this
is considered a modification by the amateur, which is permitted).

I expect that after the new rule becomes effective, there may be
other amplifiers on the market suitable for use with a K2 or other
QRP rigs (some exist now, but their legality is doubtful). The rules
prohibit an amp which can easily be modified to transmit between 26
and 28 MHz, but don't say anything about modification to increase the
gain, which I think in some cases might be done by removing an
attenuator). Since the K2's rated output is 15 W, an amp with 15 dB
of gain would have an output of 474 watts, so this wouldn't apply in
the case of 100 watt rig designed to be driven by 3.16 watts or less.

If you want an amp which will operate on 12 and 10 meters, it becomes
a bit difficult even under the new rules, since high-power filters
with steep skirts are rather impractical (rejection from 26 to
28.000, no loss at 28.001 is physically impossible). The KPA100
uses a digital signal from the K2 to know what frequency is being
amplified, but another amp might require the use of a KIO2 to provide
similar information (not quite bare bones).

Bob, N7XY
Leigh L Klotz, Jr.
2006-12-08 00:14:50 UTC
Permalink
See http://hfprojects.com.
Leigh/WA5ZNU
Post by Fred (FL)
Are there any 50 or 100 watt external amplifiers,
that a barebone QRP K2 can drive? Is anyone
using one, for SSB and CW?
Bob Miller
2006-12-08 00:22:30 UTC
Permalink
You might want to check this one out.

http://www.hfprojects.com/hfprojects/

Bob

-----Original Message-----
From: elecraft-***@mailman.qth.net
[mailto:elecraft-***@mailman.qth.net]On Behalf Of Fred (FL)
Sent: Thursday, December 07, 2006 2:23 PM
To: ***@mailman.qth.net
Subject: [Elecraft] Barebone K2 Amplifier?


Are there any 50 or 100 watt external amplifiers,
that a barebone QRP K2 can drive? Is anyone
using one, for SSB and CW?

Itch'n to build nother ...........

Thanks,
Fred N3CSY
K2 54xx, 6/06



____________________________________________________________________________
________
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Mike Short
2006-12-08 00:36:01 UTC
Permalink
I am currently building one using a Communication-Concepts AN762 amplifier
kit, and using
The band pass filter board from hfprojects. I built a case out of PC Boards,
and am currently wiring
It up. I need to take some pictures, and can make them available as it goes.

Mike
AI4NS

-----Original Message-----
From: elecraft-***@mailman.qth.net
[mailto:elecraft-***@mailman.qth.net] On Behalf Of Fred (FL)
Sent: Thursday, December 07, 2006 4:23 PM
To: ***@mailman.qth.net
Subject: [Elecraft] Barebone K2 Amplifier?

Are there any 50 or 100 watt external amplifiers,
that a barebone QRP K2 can drive? Is anyone
using one, for SSB and CW?

Itch'n to build nother ...........

Thanks,
Fred N3CSY
K2 54xx, 6/06



____________________________________________________________________________
________
Cheap talk?
Check out Yahoo! Messenger's low PC-to-Phone call rates.
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David C Dawson
2006-12-08 01:21:20 UTC
Permalink
What is the current total cost (parts + shipping, US$) of the
combination of the AN762 and the band pass filter board, including the
case and fitting?

I wanted to make a cost comparison between that plus an auto-tuner vs
the KPA100 which I understand incorporates a tuner.
(I think the amp is a 140 watt jobbie?)
Thanks.

-Dave VE7HP
Post by Mike Short
I am currently building one using a Communication-Concepts AN762 amplifier
kit, and using
The band pass filter board from hfprojects. I built a case out of PC Boards,
and am currently wiring
It up. I need to take some pictures, and can make them available as it goes.
Mike
AI4NS
-----Original Message-----
Sent: Thursday, December 07, 2006 4:23 PM
Subject: [Elecraft] Barebone K2 Amplifier?
Are there any 50 or 100 watt external amplifiers,
that a barebone QRP K2 can drive? Is anyone
using one, for SSB and CW?
Itch'n to build nother ...........
Thanks,
Fred N3CSY
K2 54xx, 6/06
____________________________________________________________________________
________
Cheap talk?
Check out Yahoo! Messenger's low PC-to-Phone call rates.
http://voice.yahoo.com
_______________________________________________
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You must be a subscriber to post to the list.
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Help: http://mailman.qth.net/subscribers.htm
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--
David Dawson

The greatest dangers to liberty lurk in insidious encroachment by men
of zeal, well-meaning but without understanding.
-- Justice Louis D. Brandeis
Bob P
2006-12-10 09:49:41 UTC
Permalink
Hi All,

I received a new 2 band ( 80 and 40M) board for my K1 and a NB.

The Saga starts:


I needed my eyes examined, I'm 64, and I have a lot of change in my lenses prescriptions, plus have beginning of cataracts in left eye, which is my good eye. Great to get old, LOL

So ordered a new pair of glasses just for computer and kit building ( big high bifocals) and will get a good pair next year when health care buck are available.

I have received from eBay a solder station and a magnifying work station light and soon will be ready to open parts packages.

Bob
Don Wilhelm
2006-12-08 02:40:36 UTC
Permalink
Fred,

Elecraft has the KPA100 which offers automatic bandswitching and a lot of
other features. It can be driven by the barebones K2 quite nicely.

Add an EC2 enclosure and you can have the KPA100 external and still with all
the function of the inboard unit - your basic K2 will still be ready to
'grab and go' as a QRP transceiver.

Pricewise - yes, it may seem like a lot in one 'ball of wax', but if you
price the components to build any external amplifier and include the
enclosure and other hardware, I believe the KPA100 price will be on a par
with others.

OTOH, you may wish to wait until Dec 15 when the restrictions on external
amplifiers that can be driven with less than 50 watts is lifted and see what
appears on the market. But I would bet that none of them will have the
operating conveinence of the K2/KPA100 combination - not to mention the
addition of the automatic tuner the KAT100 if one does not have resonant
antennas for every band.

73,
Don W3FPR
Post by Gregg R. Lengling
-----Original Message-----
Are there any 50 or 100 watt external amplifiers,
that a barebone QRP K2 can drive? Is anyone
using one, for SSB and CW?
Itch'n to build nother ...........
Thanks,
Fred N3CSY
K2 54xx, 6/06
--
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.5.432 / Virus Database: 268.15.15/579 - Release Date: 12/7/2006
1:31 PM
Tom Althoff
2006-12-08 12:27:56 UTC
Permalink
As hinted to in Don's comments there is another reason for going with the
KPA-100.

I love the fact that the KPA-100 has an integrated solid state T/R switch so
you can run full QSK.

Most of the imported amps are relay driven via the PTT line or RF sensing
with a time delay and are not able to be keyed at normal keying speeds.

Of course you could always buy an old B&W or Johnson tube T/R switch but now
your running 3 boxes with cables etc.

The KPA-100 is the "neatest" solution.

- Tom K2TA
K2 #1117

----- Original Message -----
From: "Don Wilhelm" <***@earthlink.net>
To: "Fred (FL)" <***@yahoo.com>; <***@mailman.qth.net>
Sent: Thursday, December 07, 2006 8:37 PM
Subject: RE: [Elecraft] Barebone K2 Amplifier?
Post by Don Wilhelm
Fred,
Elecraft has the KPA100 which offers automatic bandswitching and a lot of
other features. It can be driven by the barebones K2 quite nicely.
Add an EC2 enclosure and you can have the KPA100 external and still with all
the function of the inboard unit - your basic K2 will still be ready to
'grab and go' as a QRP transceiver.
Pricewise - yes, it may seem like a lot in one 'ball of wax', but if you
price the components to build any external amplifier and include the
enclosure and other hardware, I believe the KPA100 price will be on a par
with others.
OTOH, you may wish to wait until Dec 15 when the restrictions on external
amplifiers that can be driven with less than 50 watts is lifted and see what
appears on the market. But I would bet that none of them will have the
operating conveinence of the K2/KPA100 combination - not to mention the
addition of the automatic tuner the KAT100 if one does not have resonant
antennas for every band.
73,
Don W3FPR
Post by Gregg R. Lengling
-----Original Message-----
Are there any 50 or 100 watt external amplifiers,
that a barebone QRP K2 can drive? Is anyone
using one, for SSB and CW?
Itch'n to build nother ...........
Thanks,
Fred N3CSY
K2 54xx, 6/06
--
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.5.432 / Virus Database: 268.15.15/579 - Release Date: 12/7/2006
1:31 PM
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Vic K2VCO
2006-12-08 17:36:22 UTC
Permalink
Post by Tom Althoff
As hinted to in Don's comments there is another reason for going with the
KPA-100.
I love the fact that the KPA-100 has an integrated solid state T/R switch so
you can run full QSK.
Most of the imported amps are relay driven via the PTT line or RF sensing
with a time delay and are not able to be keyed at normal keying speeds.
I might as well add my 2 cents. Although I have a KPA100 I also have
another amplifier which can be used with a barefoot K2. It's a modified
Henry Radio 100B, just a pair of 2SC2876's like the KPA100 uses.

I added a set of relay-switched lowpass filters from HFProjects
<http://www.hfprojects.com/hfprojects/> and replaced the clunky t/r
relay with a pair of Aromat (Matushtita) RSD12V reed relays. These
relays are almost totally silent and more than fast enough for full QSK
at any paddle-sent speed. The filter kit is complete, inexpensive and
easy to put together.

Although you may not have an old 100B around, it would be easy to build
a similar amplifier with CCI components
<http://www.communication-concepts.com/hf_amplifiers.htm>. They sell
the boards, etc.

I use my amplifier with an Argonaut 515 that I've been playing with
(yes, I still prefer my K2). To use it with a K2, you would need to add
an amplfier keying circuit such as that on the Elecraft website.
Bandswitching can be with an external switch, or it can be automatic if
you have a KRC2.

My amplifier easily produces 140w CW (100w recommended on SSB due to IM
issues). The main advantages of the KPA100 are that it can fit in the
same box as the K2 and that it provides automatic bandswitching without
a KRC2.
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
Joseph Reed
2006-12-08 02:41:58 UTC
Permalink
Doug, Fred, and all,

I had forgotten about the 405! But you are also correct Tokyo Highpower makes two models of amplifters, a 50 watt and a 100 watt. There was also an article in QST in the last year or two that described the type of amp Fred was looking for.

Fred(FL) don't forget to check E-Bay as they frequently show up. Also subscribe to the FT-817 list on groups.yahoo.com as they are often listed. And a search of the archives will give you information on how (and whom) to contact at the factory.

Yet I concur with the majority, the KPA-100 is a nicer solution, and coupled with the KAT-100 it makes for a very sweet radio. My configuration is a K-2 with all the trimmings in QRP mode, and a KPA-100/KAT-100 in an EC-2 enclosure. It affords the best of both worlds, unplug it and it is the best QRP radio of all time, and bring it back in and you have a very good 100 watt radio.

If only the firmware could determine when it was connected to the KPA-100/KAT-100 or not and return control to the KAT-2. (Sorry Wayne <g>.)

I dont think the KPA-100 is more expensive than a Tokyo amp either.

73,
Joe N9JR

----- Original Message ----
From: Doug Person <***@Northroutt.net>
To: Fred (FL) <***@yahoo.com>
Cc: ***@mailman.qth.net
Sent: Thursday, December 7, 2006 4:36:15 PM
Subject: Re: [Elecraft] Barebone K2 Amplifier?


Long ago Ten-Tec made a model 405 amplifier. It could take 5 watts in
and produce 50 watts out. There are also some Tokyo Highpower amps
around that people have bought directly from Japan. You could also
arrange to buy one directly from the company. They technically aren't
legal because the FCC has restrictions on input power, bands and gain to
(unsuccessfully) prevent CB operators from running more than 4 watts
output. Otherwise, there are plans and boards to build a 140 watt amp
that would be quite suitable. I also believe it is possible to make the
KPA100 an external amplifier. I've used a number of these and in my
book if you want 100 watts - buy the KPA100. I built one of the first
and it was a gem.

73, Doug -- K?DXV
Doug Person
2006-12-08 07:54:16 UTC
Permalink
A few years ago, after completing my first K2, I had investigated the
Tokyo Highpower amplifiers. I exchanged emails with a salesman at Tokyo
Highpower and he was very cooperative. The delivered price of the 100
watt amp was about $450 shipped from Japan. Considering everything it
was not a bad price. But then the KPA100 was announced and the choice
was obvious. BTW my very early KPA100 went together without a hitch and
worked perfectly on all bands. I operated mostly SB with it not being
quite the cw op I am now.

73, Doug -- K?DXV
Post by Joseph Reed
Doug, Fred, and all,
I had forgotten about the 405! But you are also correct Tokyo Highpower makes two models of amplifters, a 50 watt and a 100 watt. There was also an article in QST in the last year or two that described the type of amp Fred was looking for.
Fred(FL) don't forget to check E-Bay as they frequently show up. Also subscribe to the FT-817 list on groups.yahoo.com as they are often listed. And a search of the archives will give you information on how (and whom) to contact at the factory.
Yet I concur with the majority, the KPA-100 is a nicer solution, and coupled with the KAT-100 it makes for a very sweet radio. My configuration is a K-2 with all the trimmings in QRP mode, and a KPA-100/KAT-100 in an EC-2 enclosure. It affords the best of both worlds, unplug it and it is the best QRP radio of all time, and bring it back in and you have a very good 100 watt radio.
If only the firmware could determine when it was connected to the KPA-100/KAT-100 or not and return control to the KAT-2. (Sorry Wayne <g>.)
I dont think the KPA-100 is more expensive than a Tokyo amp either.
73,
Joe N9JR
----- Original Message ----
Sent: Thursday, December 7, 2006 4:36:15 PM
Subject: Re: [Elecraft] Barebone K2 Amplifier?
Long ago Ten-Tec made a model 405 amplifier. It could take 5 watts in
and produce 50 watts out. There are also some Tokyo Highpower amps
around that people have bought directly from Japan. You could also
arrange to buy one directly from the company. They technically aren't
legal because the FCC has restrictions on input power, bands and gain to
(unsuccessfully) prevent CB operators from running more than 4 watts
output. Otherwise, there are plans and boards to build a 140 watt amp
that would be quite suitable. I also believe it is possible to make the
KPA100 an external amplifier. I've used a number of these and in my
book if you want 100 watts - buy the KPA100. I built one of the first
and it was a gem.
73, Doug -- K?DXV
Siu Johnny
2006-12-08 08:12:10 UTC
Permalink
Hi Group,

KPA100 is very good when it operates with K2. However, if you have other
non-K2 QRP rigs, you may wish to consider other 3rd party amplifiers such
as those from Tokyo High Power or HFproject. You may need an amplifier not
only restricted to the operation of K2.

I would think, before making any decision, you should think about your
operation preference. Do you want an amplifier serving K2 solely? If you
don't need the amplifier in future, can it be sold readily in the second
hand market without substantial price cut?

One thing I would like to share, the barebone K2 can drive a ICPW-1 or
Quadra System to over 300 watts. If you have the budget for the kilowatt
amplifiers in the very nearest future, you may wish to hold the purchase of
a 100 watt amplifier now.

BTW, I am waiting the coming of KPA800 / 1600 from Elecraft.

73

Johnny Siu VR2XMC

_________________________________________________________________
ÏíÓÃÊÀœçÉÏ×îŽóµÄµç×ÓÓÊŒþϵͳ¡ª MSN Hotmail¡£ http://www.hotmail.com
Tom McCulloch
2006-12-11 01:56:38 UTC
Permalink
Hi Fred,
I've built the HF Packer amp (kit) which gives my barefoot K2 a little more
oomph on PSK31. It puts out a bout 35 watts and is pretty straight forward.
The manual can be downloaded here:

http://www.hfprojects.com/projects/hfpacker/HFPackerAmp.pdf

Let me know if I can be of any further help
Tom
WB2QDG
K2 1103
======================================
When a clock is hungry, does it goes back four seconds?



----- Original Message -----
From: "Fred (FL)" <***@yahoo.com>
To: <***@mailman.qth.net>
Sent: Thursday, December 07, 2006 5:23 PM
Subject: [Elecraft] Barebone K2 Amplifier?
Post by Fred (FL)
Are there any 50 or 100 watt external amplifiers,
that a barebone QRP K2 can drive? Is anyone
using one, for SSB and CW?
Itch'n to build nother ...........
Thanks,
Fred N3CSY
K2 54xx, 6/06
____________________________________________________________________________________
Cheap talk?
Check out Yahoo! Messenger's low PC-to-Phone call rates.
http://voice.yahoo.com
_______________________________________________
Elecraft mailing list
You must be a subscriber to post to the list.
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Help: http://mailman.qth.net/subscribers.htm
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