[CTSARA] Need 3db VHF Attenuator

[Curt Seaton]

Jon and members, why are you trying to purchase another amplifier 
already???   Have you determined the actual failure of the existing 
amp?   Remember that, although I agree the amplifier is the number one 
suspect of the problem, it "could be" the switched A+ 9.5 volts that 
drives the intermediate amplifier in the Micor amplifier.  This is the 
amplifier that takes the 1/4 watt and amplifies it to the level of the 
final amplifiers.   It IS switched with the PTT command and (with the 
'found' loose screws) could have done something to the switched power 
control circuitry for that amplifier stage.   The loaner from GNARC does 
not use this voltage so it "could" be misleading.    Strongly suggest 
you try to run the Micor amp and monitor it well to see if it 
fails....    IF it does fail, then need to diagnose to find defective 
solder connection or whatever, NOWEVER, if it does NOT fail, then the 
intermediate A+ switched voltage could be the "cause" with the resultant 
effect being the amplifier is not working, eh????     I really wish you 
would spend a reasonable amount of time trying to locate the failure 
rather than trying to re-engineer a 20 + year old design that has been a 
reliable work horse for so many years by just purchasing another 
"unknown" amplifier and trying to  (er, hoping to ) integrate it with no 
interface problems....

Your 100 feet of coax is a perfectly good attenuator by the way...

Regards

Curt

On 1/9/2012 8:17 AM, Jon Perelstein wrote:
> For testing the SF 2 meter amp, I need a 3db attenuator suitable for VHF
> use to reduce the output of my HT down to about 0.25 watts (from 0.5
> watts).
>
> Anybody have one?  I can take BNC or PL-259/SO-239 connectors.  I can even
> take SMA if that's what you have.
>
> Right now, I'm using 100 ft of RG-58 to get attenuation, but it's a pain to
> work with.
>
> The good news is that the backup amp that we put into the SF repeater
> (borrowed from GNARC) worked fine during the net and snoozeline last night,
> further indicating that our problems are in the amp.
>
> Unfortunately, the amp is an integral part of the Micor repeater -- it's
> not a separate unit that's amplifying the output of a transmitter (5-25
> watts).  Instead it's taking its input from an exciter that outputs only
> 0.25 watts.  There aren't a lot of Micor amps available on the market.
>   I've been check eBay, eHam, QRZ, and Repeater-Builder, and haven't found
> any VHF amps available.  If anyone has any suggestion for additional
> sources to check ...
>
> There are a number of after-market 75-100 watt repeater amps on the market
> (e.g., Mirage), but they're almost all designed for 5-10 watts input and
> cost about $600.  With 0.25 watts input, they output only about 25 watts.
>   For $400 we can get a full 35 watt repeater (the MCC's,which are
> re-purposed GE MSTR II repeaters), so it doesn't really make sense to get
> something that outputs only 25 watts for $600.
>
> 73s
> Jon
> WB2RYV
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