http://elecraft.85.s1.nabble.com/new-mini-modules-applications-tp394184p394188.html
connectors, also available with N and SMA).
for more details. These run
$9.95 each and are real bargains. If you are serious about RF work, a
excellent investment. This will let you make up any attenuation value
from 1 dB to 78 dB in 1 dB steps. (granted, stringing all 9 attenuators
> Evening Kevin,
>
> A step attenuator capable of adding up to140db or so of loss is
> certainly very useful when working with receivers, but would be quite
> expensive I believe. If two step attenuators were used in cascade they
> would have to be built and connected in such a way that ensures that
> the attenuation in any sneak path around the attenuators at all
> working frequencies is >> 140db, and that the switched pads that make
> up the attenuators do not talk to one another via spurious paths.
>
> But even with a perfect step attenuator, the crosstalk between the
> coax cables connected to the attenuator must be considered. The
> leakage from coax such as RG-174 or RG-58 would be enough I think to
> provide a significant sneak path around a 140db attenuator, adding
> measurement error particularly so if the cables are physically close
> to one another. Double screened coax helps to reduce this problem.
> Leakage from the signal generator must also be considered.
>
> To get around these problems but still have a useful step attenuator
> for single frequency tests, I use a compromise arrangement consisting
> of a 90db step attenuator and two HP 11708A 30db fixed attenuators or
> pads with N connectors, in a way slightly similar to what you are
> suggesting. Having a fixed 30db pad right at the circuit / receiver
> under test provides a reasonable 50 ohm source, likewise a load for
> the step attenuator. The second 30db pad when used is placed at the
> generator's output. The step attenuator includes five 1db steps which
> I find to be very useful at times. Double screened coax all the way.
>
> 73,
> Geoff
> GM4ESD
>
>
> ----- Original Message ----- From: "kbgluxford" <
[hidden email]>
> To: "Elecraft Reflector" <
[hidden email]>
> Sent: Thursday, September 28, 2006 8:12 AM
> Subject: [Elecraft] new mini-modules: applications
>
>
>> Wayne and list members,
>> The AT1 step attenuator looks very interesting. However, would we
>> not need an attenuator capable of 140 db or so for receiver testing?
>> Yes we could cascade four of them, but this would scarcely be very
>> cost effective. How about supplying the same circuit board and parts
>> but with a different set of resistors to enable increases in
>> attenuation in say, steps of 40 db, which would mean that we would
>> only have to buy two kits.
>>
>> Best regards from Downunder
>> Kevin
>> VK3DAP / ZL2DAP
>
>
>
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