Re: Transmission lines, Input match and Connectors #bestpractice #experiment


jdow
 

My recent splurge was an 8664A synthesizer. A well calibrated 0dB to 40 dB would get me down easily as far as I need to go. (It would nominally make -180 dBm.) But, they'd have to be good attenuators. In the mean time I probably should get something from EBay that is "good" and nominally calibrated. It would be good to have around here. I do have some BNC coaxial attenuators I can use. I have to dig them out. It's an archeological expedition time.

{^_^}

On 20191018 16:31:16, David Eckhardt wrote:
Most of the newer professional signal generators bottom out at -130 dBm.  The 608s were microphonic as the dickens and drifted like crazy.  They were the best we had at the time.  I use good (HP) attenuators if I require levels less than -130 dBm.  Professional grade Attenuators are necessary and required equipment for any RF lab.  I really do not understand the bias against using them other than adding another error bar to a measurement where they are used.
Dave - WØLEV
Dave - WØLEV
On Fri, Oct 18, 2019 at 11:22 PM jdow <jdow@... <mailto:jdow@...>> wrote:
Si. Of course, if I did not mind a lot of up front attenuation a waveguide
beyond cutoff attenuator as in the venerable HP-608 series would be REALLY
interesting. They work surprisingly well. (I still own a 608F. It's fun when
you
develop a transceiver that you can feed a -109 dBm signal and not be able to
jam
it with the 608F fed through a 20 dB coupler. That's more than 1mW of jammer at
the radio input. I reversed the coupler and made the transceiver collapse when
the input got high enough to cause gain compression. Hedy Lamar had a really
good idea. It works.)
{^_-}
On 20191018 15:46:55, Dana Myers wrote:
> On 10/18/2019 3:38 PM, jdow wrote:
>> I haven't quantized it. 20 or 30 dB would probably be close. (Airgaps
can work
>> as attenuators if you are REALLY delicate creating the tiny gap. Just don't
>> ask for precision. {^_-})
>
> "Really small" air-gaps are *always* capacitors, right?
>
> 73,
> Dana  K6JQ
>
>
>
>
--
*Dave - WØLEV
*
*/Just Let Darwin Work/*
*/Just Think/*

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