[CQ-Contest] ICE 419 Band Pass Filter Capacitors

K4RO Kirk Pickering k4ro at k4ro.net
Fri Jul 27 12:31:00 PDT 2012

I recently overhauled a pair of original ICE 419 BPFs. One had a blown 
10M section, and the other one had a blown 20M section. While I was 
inside them, I wrote down the values of the capacitors that were used 
for each build. As the document from ICE states, "as-bulit values may 
differ from design values." So just for documentation's sake, I wrote 
down the as-built values in a spreadsheet. I also included a scan of 
each filter's SWR curves into a 50 ohm dummy load, after tweaking 
component mounting positions to tune each filter. Note that these were 
early 419 models, not the A or B revisions. I added bypass caps on the 
sink-to-ground lines and the LEDs to upgrade them. Anyone interested may 
compare the various filter capacitor values here:


For now, I'm just replacing the burnt capacitors with spares that I got 
from ICE many years ago. While I'm waiting for these to burn up :-) I'll 
order some of the CDV16 caps for the future.

73, Kirk K4RO

On 7/9/2012 8:39 AM, Dave Hachadorian wrote:
> Yesterday (email below) I recommended some capacitor replacements
> for the ICE 419 bandpass filter box.  I see that Mouser now
> carries a decent stock of the CDV16 series of capacitors, which
> should be even better for this application.
> I would replace the 10 meter caps with THREE of these:
> http://www.mouser.com/ProductDetail/Cornell-Dubilier/CDV16FF181JO3/?qs=tNDx7qEChkdVeXCTyip0gJ%2fmhJL9ji8%2f8EI0jS5RcxY%3d
> Replace the 15 meter caps with THREE of these:
> http://www.mouser.com/ProductDetail/Cornell-Dubilier/CDV16FF221JO3F/?qs=tNDx7qEChkcTDRralVBIS8sa%2ftpHGOIpu6bFpqfKA4o%3d
> Thanks to K1TTT for pointing out the advantages of the CDV16
> series.
> Dave Hachadorian, K6LL
> Big Bear Lake, California
> -----Original Message-----
> From: Dave Hachadorian
> Sent: Sunday, July 08, 2012 1:07 PM
> To: Keith Dutson ; cq-contest reflector
> Subject: Re: [CQ-Contest] Bandpass filter
>> I use the ICE 419 banpass filters... Ten meters is by
>> far the most vulnerable section.  I have a large supply of 270pf
>> 500v silver
>> mica caps on hand to make repairs.  Two of these caps are wired
>> in parallel
>> to get 540pf for the tank circuit.  If I could find caps rated
>> at
>> 1000v, I
>> would use them.
> It's the current, not the voltage that causes capacitors in the
> ICE filters to heat up and change value.  The ones that fail are
> the caps that go to ground on the radio side (not the antenna
> side) of the pi-net.  I helped a friend service his unit, and we
> replaced the 10 meter caps with THREE of these:
> http://www.mouser.com/ProductDetail/Cornell-Dubilier/CDV19FF181JO3F/?qs=tNDx7qEChkfCDH5GStQHlaNECvkBqF%2f36Qk9E0aHa4Q%3d
> We also replaced the 15 meter caps with THREE of these:
> http://www.mouser.com/ProductDetail/Cornell-Dubilier/CDV19FF221J03F/?qs=xO%2fDY4w9KHXzyyfzgPGBl2oCX1GQe4%2frV%2f%252bpZRIlAxM%3d
> Dave Hachadorian, K6LL
> Big Bear Lake, California

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