[TowerTalk] Using Stubs to Reject Harmonics

[Michael Tope]

On 2/4/2010 12:50 AM, Jim Brown wrote:
> On Wed, 3 Feb 2010 20:24:47 EST, TexasRF at aol.com wrote:
>
>    
>> For example, a 100ft length of RG213 has about 10 dB loss at 432 MHz
>>      
> That would be some pretty awful coax -- Belden's RG8X (9258) is only
> 6.6dB/100 ft at 400 MHz, and a decent RG8-sized coax is on the order of
> 3dB/100 ft.
>
> Yes, an infinitely long line looks like a resistor equal to its own Zo,
> even with an open circuit as a load but it takes more like 1,000 ft to
> approach that at 432 MHz.
>
> 73,
>
> Jim K9YC
>
>    

Looks like solid dielectric RG-213 is about 5dB/100' at 432 MHz, Jim. 
Gerald, you must have lost a factor of 2 somewhere (200' ft of RG-213 
would have 10dB one-way loss). Coax with a foamed polyethylene 
dielectric in RG-8 size (0.405" OD) is around 3dB/100' @ 432.

73, Mike W4EF......................