[TowerTalk] Control of ICE 419A Bandpass Filter

[Jim Thomson]

Date: Thu, 20 Jun 2013 12:34:08 -0700
From: Jim Brown <jim at audiosystemsgroup.com>
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Control of ICE 419A Bandpass Filter

On 6/20/2013 12:15 PM, Allen Brier N5XZ wrote:
> I will be getting an ICE 419A Bandpass filter soon at a good price. Wondering what is the best way to control it with a K3. Suggestions?

Sorry to be the bearer of bad tidings, but the "good price" for ICE 
419-series filters is free.  Several common problems.

#1, the relays get very flaky, and are hard to replace.  Spraying them 
with the "right" contact cleaner is about the best you can do.

#2, the filters don't handle anything close to rated power, and even 
relatively small SWR (1.5:1) makes it worse.  It's common for them to 
fail (blown capacitors) with 100W.  They'll probably be OK at the 40-50W 
level needed to drive an amp.

#3, even when they're working they're not great filters.

#4, every ICE filter I've ever bought, new or used, was out of alignment 
(high SWR, tuning not right).  A filter that is out of alignment is more 
likely to fry.

73, Jim K9YC

##  I have the ICE 300 watt  HP  filter that has a cut off of 1.7 mhz.  Right out of the box...
and into a dummy load, the swr was a bit flaky on 80m.    On 160M,  with 200w cxr applied,  it was
only 150 w  on the output of the ICE  HP filter.  The caps  were fried !    Caps were replaced with several
lower value caps in parallel.   It was not a peak V problem either.  It was a current handling issue with the caps.

##  at the time we had 10 kw AM stations  on 900 khz and also 1070 khz.....and also a 50 kw station on 1200 khz. 
All  3 of em were on small islands just off shore 2 miles from me.   The ICE filter had about 15-18 db attenuation at 1200 khz...
and 50 db at 550 khz. 

##  all the caps had to be replaced as described.... just so it would handle 200 w pep on ssb/ cw...into a flat swr. 
I looked at their bandpass filters and passed on em, just not robust enough for me. 

Later... Jim   VE7RF