[TowerTalk] ICE 419A Combination Bandpass Filter 10M Section Blown

[Jeff Goldman]

I agree on the current problem view point on the filter failure.  I had 
an ICE 6 meter filter that was rated at 250 watts, and it went out 
several times with the stock caps.  I finally replaced the original 
caps (I think they were 50 pf each) with a parallel set of 5 10pf caps 
of the original type, and no more problems since.   This divides the 
current through each, and reduces the loss (heat) which destroys caps, 
just like too much voltage.

73,
Jeff, K3DUA


On Dec 10, 2004, at 5:29 PM, Tom Rauch wrote:

>> Each filter section apparently consists of a simple coil
> and two caps in T
>> configuration.  This is only an observation as I do not
> have a schematic.  I
>> would like to beef up the capacity and assume this might
> be done with higher
>> voltage caps.
>
> It can also be a current problem. You really should look at
> component ratings and the actual current in the "tank". Just
> by knowing the component values you can calculate the
> required voltage and current ratings of the capacitors.
>
> Remember when you reduce power, the voltage and/or current
> decreases to half at 1/4th the original power.
>
> Moving from 200W to 150W will still leave you with almost
> 87% of the original component stress.
>
> You really should have more headroom than that. For example
> the output filters in the ALS-600 will handle over 1500
> watts for extended operating time without actually failing.
> That headroom is required to make them reliable at 600
> watts.
>
> 73 Tom
>
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