Just wonder, what is the reason for such a requirement?
The requirement goes back to the 1970's and is designed to prevent
amateur amplifiers from being used for unlicensed ("freeband")
operation with 5 Watt CB exciters. The intent was to match the
gain needed to reach the US legal output power with the drive
available from the typical exciter power level.
For the Expert amplifiers to show 22 dB gain, they must be shipping
without the attenuator or the distributor is removing the attenuators
- both of which violate the type acceptance. On a deeper level, to
design an amplifier with that much gain is bad design - part of the
excess gains should be used for negative feedback to reduce IMD and
improve stability.
73,
... Joe, W4TV
On 2015-04-03 1:30 AM, Igor Sokolov wrote:
Joe,
As I was told, they ship it with the pad at the input to meet FCC
requirement of max 15db gain. But the pad can be easily bypassed. Just
wonder, what is the reason for such a requirement?
73, Igor UA9CDC
----- Original Message ----- From: "Joe Subich, W4TV" <[email protected]>
To: <[email protected]>
Sent: Friday, April 03, 2015 7:48 AM
Subject: Re: [Elecraft] Question K3 ALC w/SPE Expert 1.3K-FA amp
This is because the software in the amp automatically reduces the
power in the rig to the best output level for the amp (on the amp
LOW=500W out= 3W drive, MID= 1000W out= 6W drive, HIGH = 1500W out =
9W drive). It works flawlessly. Actually, I could leave the power on
the Pro III untouched, and the amp reduces the power accordingly.
Is SPE shipping amplifiers that violate type acceptance or did you
modify that amplifier? Any commercial amplifier sold in the US can
have a maximum gain of 15 dB. Your Expert 1.3K-FA shows 22 dB -
nearly 6 dB above the limit.
73,
... Joe, W4TV
On 2015-04-02 10:34 PM, AB2E Darrell wrote:
Hello all,
I am the proud new owner of a new K3. I am also the proud new
owner of an SPE Expert 1.3K-FA solid state amp, and I have a question
for the group regarding interfacing the K3 to the amp.
My current setup is using my Icom 756 Pro III with the SPE Expert
1.3K-FA. The recommended setup for Icom was to connect both the Relay
and ALC cables between the rig and amp. This is because the software
in the amp automatically reduces the power in the rig to the best
output level for the amp (on the amp LOW=500W out= 3W drive, MID=
1000W out= 6W drive, HIGH = 1500W out = 9W drive). It works
flawlessly. Actually, I could leave the power on the Pro III
untouched, and the amp reduces the power accordingly.
My question for the group is, is there a way to allow the K3's output
to be controlled by the amp? I see the note on p27 about not using an
amp to control the K3's output, but wonder if there is a safe way to
do it. For instance, could the K3 be set to say 15W out on all bands
via the menu, then allow the amp to control the output via ALC for
optimum drive?
Any info and comments appreciated.
73 Darrell AB2E
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