http://elecraft.85.s1.nabble.com/new-mini-modules-applications-tp394184p394189.html
etc., all at reasonable prices. If you're building up a test bench, you
loads. They have excellent quality and service.
> If you can't find suitable fixed attenuators at the local swap meet, I
> can highly recommend MiniCircuit's inexpensive HAT-series (with BNC
> connectors, also available with N and SMA).
>
http://www.minicircuits.com/dg03-152.pdf for more details. These run
> $9.95 each and are real bargains. If you are serious about RF work, a
> set of these in the steps 1, 2, 3, 6 (x2), 10 (x2) and 20 dB (x2) is
> an 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 in series for 78 dB is a bit awkward, but you get the idea.)
>
> I know Minicircuits has a UK distributor, not sure about VK-land.
>
>
> Jack
>
>
>
> Geoffrey Mackenzie-Kennedy wrote:
>> 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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