Topband: RF attenuators

[ZR]

Ive tested dozens of CATV splitters over 25 or so years and they range from 
falling apart as high as 7-8MHZ and many good to 80 but useless at 160.
By good I mean at least a 10dB RL (2:1 VSWR) and 20dB isolation.

For the cost of 3 small ferrite cores, some wire and a resistor its 
certainly simple to build much better ones.

Carl
KM1H


----- Original Message ----- 
From: "Bill Wichers" <billw at waveform.net>
To: <jim at audiosystemsgroup.com>; <topband at contesting.com>; "Hardy Landskov" 
<n7rt at cox.net>
Sent: Wednesday, August 24, 2011 10:46 AM
Subject: Re: Topband: RF attenuators


> It would be easy to check if an attenuator is resistive or capacitive by
> checking if it will pass any DC. If the attenuator is all resistive you
> should be able to measure a low (relatively, i.e. not megohms)
> resistance between the ports and between the center pin and ground.
>
> Regarding the splitters not being useable down low in frequency, I think
> I have one of their 10-1000MHz 2-way splitters at home that I can test
> down around 1 and 2 MHz easily enough and post the results.
>
>  -Bill
>
> [snip]
>> In general, many VHF/UHF attenuators are built with capacitive
> dividers
>> rather than resistive dividers, and are unlikely to be useable at HF
> and
>> below.  Conversely, simple resistive attenuators are quite suitable in
>> the 2 MHz range, provided that they are made with resistors that are
> not
>> inductive, whereas their stray L and C would render them useless at
>> higher frequencies.
>>
>> 73, Jim Brown K9YC
>> _______________________________________________
>> UR RST IS ... ... ..9 QSB QSB - hw? BK
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 10.0.1392 / Virus Database: 1520/3854 - Release Date: 08/24/11
>