[TowerTalk] Polyphaser vs. ICE

[Kipton Moravec]

While the power rating (W) says you can use a 1/4 W resistor, the
voltage does not. 

Carbon Film Resistors have maximum working voltages for their size.
(From Xicon Datasheet)

1/8 W  200V
1/4 W  250V
1/2 W  350V
1 W    500V

So I would use a 1 W resistor.

Kip


On Tue, 2011-05-17 at 12:52 -0400, Gary Schafer wrote:
> 1500 watts is 386 volts peak from the RF.
> A 1 meg ohm resistor across that will have a peak current of 386 micro amps.
> That is .15 watts that the resistor will have to dissipate.
> 
> Old ohms law sure is useful. :>)
> 
> Keep in mind that not surge devices are necessarily the same. A unit made
> for one frequency range may have different firing points at different
> frequencies.
> 
> 73
> Gary  K4FMX
> 
> > -----Original Message-----
> > From: towertalk-bounces at contesting.com [mailto:towertalk-
> > bounces at contesting.com] On Behalf Of k2wd at comcast.net
> > Sent: Tuesday, May 17, 2011 12:32 AM
> > To: towertalk at contesting.com
> > Subject: [TowerTalk] Polyphaser vs. ICE
> > 
> > I am using a number of Polyphaser units in line just before my cables
> > enter my home. I have opened them in the past to discover that there is
> > nothing more than a surge device from the center pin of the antenna side
> > connector to ground, then a capacitor from the antenna side center pin
> > to the radio side center pin. Matter of fact, I converted some UHF range
> > units to HF range by simply replacing the capacitor with the same value
> > used in a factory built HF range unit (I forget the exact value  at the
> > moment but it was either a 0.1 or 0.01uF disc).
> > 
> > This does not provide any kind of static dissipation. Can I simply open
> > them up and add a 1Mohm resistor in parallel to the surge device
> > (antenna center pin to ground) to allow for static dissipation?
> > 
> > Or will this affect the original performance of the unit?
> > 
> > If this is ok, will a 1/4w or 1/2w resistor handle 2kw key down? I don't
> > think anything larger will fit inside. So far the stock Polyphaser units
> > have passed the key down test.
> > 
> > Thanks
> > Eric
> > K2CB
> > Sent on the SprintR Now Network from my BlackBerryR
> > 


-- 
Kipton Moravec AE5IB .- . ..... .. -...

"Always do right; this will gratify some people and astonish the rest."
--Mark Twain