On Thu, 20 Nov 2003 08:35:58 -0700, "Ken Bessler"
wrote:

HF Pack's K5OOR amp build IV is nearing it's release
date. The amp accepts 1-2 watts drive to produce 35-40
watts output. The amp runs class AB and is bandswitched.
Operates 160, 80, 75, 60, 40, 30, 20, 17, 15, 12 & 10
meters. New to build IV is tha addition of 60 meters.

What if the exciter (a ten tec 1320) puts out 4 or 5 watts cw, and
there's no convenient way to lower the output? Would that overdrive
the amp?

Bob
k5qwg



Cost of the amp is only $122 for the complete kit. You
can see details for this project at:

http://www.hfprojects.com/

Pictures of the amp are at:

http://www.hfprojects.com/v2/modules...showpage&pid=1

Note: This project complys with FCC Regulations
97.3(a)(19), 97.515, and 97.317. Recently, K5OOR
built and tested such an amplifiers under 97.315(b)(3)(i).
It is understood that this activity was consistent with the
Regulations.

Currently, the group is waiting for a few more ops to sign
on to the project - we need a total of at least 100 members
to order the parts. Currently we have about 50 signed up.

Also, I read somewhere that this may be the last run for
this series so you may want to jump on the band wagon
before the chance slips away!

After this project is gone the only bandswitched legal QRP
drive amps will be the ones like the Tokyo High Power
HL50B ($300+ for 50w).

So join our group and have the pride of announcing to
the other end of a QSO that you are running a homebrew
amp!

http://www.hfprojects.com/signup/signup.html

73's de Ken KG0WX

"Bob Miller" wrote in message
news
What if the exciter (a ten tec 1320) puts out 4 or 5 watts cw, and
there's no convenient way to lower the output? Would that overdrive
the amp?

Bob
k5qwg

Morning, Bob - I emailed K5OOR Virgil with your question but
in the mean time I looked at the schematics. The incoming signal
is fed through an attenuator. This attenuator (r2, r3 & r4) can be
set up for specific rigs. Here is the matrix:

DB R3 R2 R4 IN OUT RIG
3 300 18 300 2.0 1.0 K2
4 220 24 220 2.5 1.0 FT-817
5 130 43 130 3.0 1.0 Other

As you can see, the amp really needs only 1 watt of drive. It
would be very simple to make a pad to attenuate your 5w
down to 1w. A 6db pad would take 4w down to 1w but
5w would be 1.25 watts, a little much so I'd go with a 7db
pad - according to my math that would be just right.

Hope that helps,
Ken KG0WX

Morning, Bob - I emailed K5OOR Virgil with your question but
in the mean time I looked at the schematics. The incoming signal
is fed through an attenuator. This attenuator (r2, r3 & r4) can be
set up for specific rigs. Here is the matrix:

DB R3 R2 R4 IN OUT RIG
3 300 18 300 2.0 1.0 K2
4 220 24 220 2.5 1.0 FT-817
5 130 43 130 3.0 1.0 Other

As you can see, the amp really needs only 1 watt of drive. It
would be very simple to make a pad to attenuate your 5w
down to 1w. A 6db pad would take 4w down to 1w but
5w would be 1.25 watts, a little much so I'd go with a 7db
pad - according to my math that would be just right.

Update - Virgil just sent me the specs on a 7db pad:

DB R3 R2 R4
7 130.7 44.8 130.7

hope that helps,

73's de Ken KG0WX

Morning, Bob - I emailed K5OOR Virgil with your question but
in the mean time I looked at the schematics. The incoming signal
is fed through an attenuator. This attenuator (r2, r3 & r4) can be
set up for specific rigs. Here is the matrix:

DB R3 R2 R4 IN OUT RIG
3 300 18 300 2.0 1.0 K2
4 220 24 220 2.5 1.0 FT-817
5 130 43 130 3.0 1.0 Other

As you can see, the amp really needs only 1 watt of drive. It
would be very simple to make a pad to attenuate your 5w
down to 1w. A 6db pad would take 4w down to 1w but
5w would be 1.25 watts, a little much so I'd go with a 7db
pad - according to my math that would be just right.

Update - Virgil just sent me the specs on a 7db pad:

DB R3 R2 R4
7 130.7 44.8 130.7

hope that helps,

73's de Ken KG0WX

"Bob Miller" wrote in message
news
What if the exciter (a ten tec 1320) puts out 4 or 5 watts cw, and
there's no convenient way to lower the output? Would that overdrive
the amp?

Bob
k5qwg

Morning, Bob - I emailed K5OOR Virgil with your question but
in the mean time I looked at the schematics. The incoming signal
is fed through an attenuator. This attenuator (r2, r3 & r4) can be
set up for specific rigs. Here is the matrix:

DB R3 R2 R4 IN OUT RIG
3 300 18 300 2.0 1.0 K2
4 220 24 220 2.5 1.0 FT-817
5 130 43 130 3.0 1.0 Other

As you can see, the amp really needs only 1 watt of drive. It
would be very simple to make a pad to attenuate your 5w
down to 1w. A 6db pad would take 4w down to 1w but
5w would be 1.25 watts, a little much so I'd go with a 7db
pad - according to my math that would be just right.

Hope that helps,
Ken KG0WX