I don't have a 250 Hz filter, but both of my 400 Hz ones do require a few dB. I am more
surprised that your main filter requires NO boost, than that your sub requires 6 dB. How
much do others who have 250 Hz filters use?
On 4/3/2013 6:32 PM, Jim Miller wrote:
I spent some time last night playing with various filter settings via the K3 utility.
What I found is that the 250 8p filter in the main required no boost to maintain signal
level as I dialed down the bandwidth and engaged it. The suspect one in the subrx
required 6db of boost.
Has anyone else seen this level of boost required?
With the subrx bandwidth increased to be just above its 250hz8p filter the receiver
comes alive nicely.
I'll open up the K3 this weekend and do a filter inspection to see if there is some crud
on the pins and try a filter swap to the main just to verify my suspicion of a bad filter.
I may have to order another...
jim ab3cv
On Wed, Mar 27, 2013 at 12:55 AM, Vic K2VCO <k2vco....@gmail.com
<mailto:k2vco....@gmail.com>> wrote:
Make sure the filter gain compensation is set properly for the 250 Hz
filter. The
easiest way to do it is from the filter configuration screen of the K3
utility.
On 3/26/2013 5:44 PM, Jim Miller wrote:
Just used the K3 utility to disable the 250 8p on the sub and the audio
now
is balanced regardless of sub bandwidth. Of course the noise level
changes
but no imbalance with strong or weak sigs between the two.
Now to figure out if it's the socket or the filter at fault.
jim
On Tue, Mar 26, 2013 at 8:22 PM, Jim Miller <j...@jtmiller.com
<mailto:j...@jtmiller.com>> wrote:
I think I've figured out why my subrx seems to be much less
sensitive than
the main. I was playing around with the bandwidth control today
while
having the VFOs linked.
I have the same filter setup in main and sub, a 2.8K and a 250hz,
both 8
pole. I have both main and sub set to cut to the 250 at 350hz. I do
most of
my Dx activity with the BW set to 350 so engaging the 250hz filter.
What I noticed is that although the sub is much less sensitive than
the
main with the 250 engaged it is just fine just above where the
filter kicks
in.
This tells me that something is wrong with the filter or the socket
it is
in. The balance control has to be set past 3 oclock to even out the
signals
with the 250 engaged in the sub. The balance is just fine however
when that
filter isn't engaged.
I'm going to try moving the filter to another socket in the sub to
see
what effect that has.
I can also try swapping the 250 between the sub and the main to see
if the
loss of sensitivity tracks the filter placement.
Any other ideas?
It could be a bad filter. I don't think the filters should be that
different in loss when in spec.
jim
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