[Amps] ALPHA 89

[Robert]

The Alpha 89 uses same board one on input, one on output.  
Some resistors are different for different power levels.
http://www.alpharfsystems.com/wp-content/uploads/2016/05/89_full_schematics.
pdf
Power out and reflected power on output have dedicated set of LEDs.
Note, output power is shown, not output SWR (not sure why input is SWR).

When I first bought the amp, the input drive and SWR functions tied to the
lower set of LEDs wouldn't function.
I'm not sure why it's reflected Watts on output and SWR on input....
Replaced the set of diodes on input board and these functions worked again,
hence my thinking is that lower set of LEDs are input related.

On another Alpha 89 note, Thanks to K0HM for suggesting using six foot piece
of coax on input.  Didn't have an exact six footer, longer coax on input and
SWR on K3 is now a happy 1.4    I'm not sure how that worked but smiling and
moving on!


73 W5AJ

Robert
Midland, Texas

-----Original Message-----
From: Amps [mailto:amps-bounces at contesting.com] On Behalf Of Jim
Sent: Sunday, March 15, 2020 12:51 PM
To: amps at contesting.com
Subject: Re: [Amps] ALPHA 89

The LEDs on the amplifier would show the OUTPUT SWR not the input SWR that
the radio sees...

Are you confusing the issue?


Thanks
73
Jim W7RY

On 3/14/2020 5:52 PM, BRADLEY FOCKEN wrote:
> Hello Robert,
> The 89 was set up using a 6 foot length of RG58.
> Try that and see what you get then it should be below 1.5. I would not
recommend messing with the tuned input as it will cause the next person a
similar problem.
> 73
> Brad K0HM
>
> Get Outlook for Android<https://aka.ms/ghei36>
>
> ________________________________
> From: Amps <amps-bounces at contesting.com> on behalf of Robert 
> <woodr90 at gmail.com>
> Sent: Saturday, March 14, 2020 4:32:47 PM
> To: Amps at contesting.com <Amps at contesting.com>
> Subject: [Amps] ALPHA 89
>
>
>
> I have Alpha 89 on test bench, it's an amp I've used for several years 
> and decided to sell.
>
>
>
> On 40 meters the Alpha input SWR, using the Alpha LEDs about 1.2 to 1
>
> The K3 reads 2.9 to 1
>
> An outboard MFJ meter shows 2.5
>
>
>
> I've tried different coax jumpers, lengths, etc.
>
> SWR improves (2.9 best) as increase Alpha to 1500 Watts output but at 
> ten watt "Test" output of K3, the SWR indicates on K3 near 15 to 1
>
>
>
> Bands outside 40/80 are fine.   80 is more 2 to 1 input, other bands, 1.1
to
> 1.
>
>
>
> Thoughts??
>
>
>
> 73 W5AJ
>
>
>
> Robert
>
> Midland, Texas
>
>
>
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