> The problem is that Ameritron is sloppy with their design.
> The amplifier board in the ALS-600 is almost a part for part
> copy of the Helge Granberg/Motorola application note EB104.
> The amplifier has a high power gain - in excess of 20 dB for
> the transistors - with a gain variation of as much as 4 dB
> depending on construction across the 1.5 to 30 MHz operating
> range. Ameritron then choose to use ALC to control transmitter
> output and accommodate this overdrive.
>
> When ALC is used to reduce the output from most modern solid
> state transceivers they do become very "dirty." Instead of
> ALC, the Granberg design should be used with 6 or 7 dB of
> fixed attenuation up to 6 DB of variable attenuation (1, 2
> and 3 dB fixed attenuators) that can be switched into the
> circuit on a per band basis. This allows the amplifier to
> operate linearly with the full output of most modern solid-
> state transceivers - a situation that allows for minimum
> ALC and optimal operation.
>
> The same considerations apply to the ALS-1300 which is likely
> to be very similar to the ALS-600 with two Grasberg amplifier
> modules and a splitter/combiner.
Ameritron had an ALS-1300 with clear cover in their display at
the Orlando Hamcation last weekend. The physical construction
looks reasonable - perhaps a bit above normal for them. It
is most certainly built with two of the Granberg design RF
modules and splitter/combiner. The lowpass filter assembly
has been beefed up over the one in the ALS-600. However, the
amplifier relies far too much on ALC instead of switched
attenuators (by band) or a gain compensating network to control
drive and output power.
At roughly $2900 list, the ALS-1300 is interesting when compared
with other "higher power" solid state offerings like the PW-1,
Quadra and HL-2.5Kfx. However, it is not cost effective when
compared with the AL-572 at the same power level for $1700 or
full power amplifiers like the AL-82 (2 x 3-500Z) and AL-800HF
(2 x "imported" 3CX800) at $2700.
73,
... Joe, W4TV
> -----Original Message-----
> From: amps-bounces@contesting.com
> [mailto:amps-bounces@contesting.com] On Behalf Of Joe Subich, W4TV
> Sent: Monday, February 09, 2009 5:04 PM
> To: 'Rob Atkinson'; amps@contesting.com
> Subject: Re: [Amps] ALS-1300
>
>
>
> > I've been told the Ameritron s.s. amps are easily overdriven
> > into "garbageland" where they spew noise up and down the
> > band. I know this can be done with any amp but they have a
> > rep. for being especially prone to do this.
>
> The problem is that Ameritron is sloppy with their design.
> The amplifier board in the ALS-600 is almost a part for part
> copy of the Helge Granberg/Motorola application note EB104.
> The amplifier has a high power gain - in excess of 20 dB for
> the transistors - with a gain variation of as much as 4 dB
> depending on construction across the 1.5 to 30 MHz operating
> range. Ameritron then choose to use ALC to control transmitter
> output and accommodate this overdrive.
>
> When ALC is used to reduce the output from most modern solid
> state transceivers they do become very "dirty." Instead of
> ALC, the Granberg design should be used with 6 or 7 dB of
> fixed attenuation up to 6 DB of variable attenuation (1, 2
> and 3 dB fixed attenuators) that can be switched into the
> circuit on a per band basis. This allows the amplifier to
> operate linearly with the full output of most modern solid-
> state transceivers - a situation that allows for minimum
> ALC and optimal operation.
>
> The same considerations apply to the ALS-1300 which is likely
> to be very similar to the ALS-600 with two Grasberg amplifier
> modules and a splitter/combiner.
>
> 73,
>
> ... Joe, W4TV
>
>
> > -----Original Message-----
> > From: amps-bounces@contesting.com
> > [mailto:amps-bounces@contesting.com] On Behalf Of Rob Atkinson
> > Sent: Monday, February 09, 2009 1:18 PM
> > To: amps@contesting.com
> > Subject: Re: [Amps] ALS-1300
> >
> >
> > I've been told the Ameritron s.s. amps are easily overdriven
> > into "garbageland" where they spew noise up and down the
> > band. I know this can be done with any amp but they have a
> > rep. for being especially prone to do this.
> >
> > The price of the ALS-1300 means one more nail in the coffin
> > of the Ten Tec Centurion I fear, since Ten Tec boosted it
> > into the over $3000 league. Maybe that was part of the
> > Ameritron plan. More sales of AL-82s hi hi.
> >
> > 73,
> >
> > rob / k5uj
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