[AMPS] RE:two questions

[Rich Measures]

>> From:          Peter Chadwick <Peter.Chadwick@gpsemi.com>
>> Date:          Mon, 8 Sep 97 14:18:09 +0000
>
>Measures wrote:
>> >-  The advantage of resistance-wire suppressors is that, at 100MHz,
>> >they exhibit about 40% less Rp than do otherwise similar, conventional 
>> >suppressors made from copper-wire. 
>
>You replied: 
>> Is this  40% less Rp than the 'conventional'  parasitic suppressor i.e.
>> coil and shunt resistor, or just 40% less Rp than the coil alone?...
...snip...
>If you look at N7WS's data, and his conclusions, the stock AL-80B 
>suppressor is essentially equal to the nichrome model near 
>the frequency where stability is a problem, although the stock 
>suppressor does lower SYSTEM Q at VHF slightly more than the 
>nichrome replacement.   

Good advice, Mr. Rauch.  I looked.  How could Wes have been measuring 
'SYSTEM Q'?  The suppressors he measured were not installed in an 
amplifier?  At the frequency nearest to the AL-80's 155MHz anode 
resonance, 150MHz, Wes measured the copper-wire suppressor's Rp at 166 
ohms, and the resistance-wire suppressor's Rp at 103 ohms.  

>The "advantage"  of the nichrome really kicks in at HF, as evidenced 
>by the heat produced and efficiency lost on upper HF when the 
>nichrome suppressor is added.

Evidence is norally measured.  Does it seem plausible that the resistance 
of Ni-Cr alloys 'kick in' and starts increasing below 30MHz?  Does it 
seem likely that the resistance starts decreasing above 30MHz?
(Twilight Zone Theme)

>2.)  A direct short has an Rp of  zero ohms.
>
It seems that Mr. Rauch admittedly missed the boat on admittance (Y).  A 
direct short sends Rp up through the roof. 

Rich--- .

R. L. Measures, 805-386-3734, AG6K   


--
FAQ on WWW:               http://www.contesting.com/ampfaq.html
Submissions:              amps@contesting.com
Administrative requests:  amps-REQUEST@contesting.com
Problems:                 owner-amps@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm