Swapping Standard 2.7 kHz 5-pole Filter


bill_w4zv <w0zv@...>
 

According to Monica at Elecraft, it's possible to swap
the standard 2.7 kHz 5-pole filter for either the 2.8 kHz 8-pole or
the 400 Hz 8-pole for an incremental $90 ($30 credit plus the
standard $120 charge for 8-pole filters), but only the 2.8 kHz
and 400 Hz may be substituted for the standard filter.

Now if we only knew if there were any difference in
IMD/BDR performance we could make a rational decision...

73, Bill W4ZV


neal
 

Or just order all of the filters, five in each of the two receivers
and run your own evaluations. A true metrologist....Since I have no
antennas I could afford that option.

--- In Elecraft_K3@yahoogroups.com, "bill_w4zv" <w0zv@...> wrote:

According to Monica at Elecraft, it's possible to swap
the standard 2.7 kHz 5-pole filter for either the 2.8 kHz 8-pole or
the 400 Hz 8-pole for an incremental $90 ($30 credit plus the
standard $120 charge for 8-pole filters), but only the 2.8 kHz
and 400 Hz may be substituted for the standard filter.

Now if we only knew if there were any difference in
IMD/BDR performance we could make a rational decision...

73, Bill W4ZV


bill_w4zv <w0zv@...>
 

I received the following correction from Eric WA6HHQ. I did get my
previous info directly from Elecraft but apparently miscopied her name.

Hi Bill,

This is incorrect. The 2.7 kHz 5-pole can only be swapped for a 2.8
kHz or possibly the 2.1 kHz 8 pole filters. We require at least one
SSB b/w filter in each K3 as it ships since we must also transmit
through the filter for SSB and data modes. Transmitting through the
2.1 kHz filter will limit your tx bandwidth to that value. ( I'm not
aware of many choosing the 2.1 as their only SSB filter - I may drop
that as a swap option to make sure no overly narrow TX K3s get out
there and confuse the market.)

I'll post some more detailed DR numbers on the 5 pole vs 8 pole
filters in the next couple of days. The short answer is that the 5
pole filters have slightly less IMD3 dynamic range and a wider shape
factor than the 8 pole filters, but both are very good. The 250 Hz
8-pole and the 200 Hz 5 pole are both at least 95+ dB DR3 at 5 kHz,
with the 8 pole beating out the 5 pole by several dB. We've been
testing a number of each filter on a range of K3s to make sure we can
conservatively spec them across filter variations and rig variations. :-)

One other note - The sales person you talked to is Annika. There is no
Monica at Elecraft, unless they are hiding her somewhere! ;-) She was
clear on which filters could be swapped for the 2.7, but I'll check
with her for sure tomorrow.

73, Eric WA6HHQ
(Now back to work!)


bill_w4zv <w0zv@...>
 

--- In Elecraft_K3@yahoogroups.com, "neal" <nealwh@...> wrote:

Or just order all of the filters, five in each of the two receivers
and run your own evaluations. A true metrologist....Since I have no
antennas I could afford that option.
You'll need ~$1100 for the filters plus two HP 8640B Signal
Generators, a couple of precision attenuators, a hybrid combiner and a
True-RMS responding meter (and some other bits and pieces).

Where I live you could buy several acres for that amount and put up
some decent antennas! :-)

73, Bill


neal
 

Had all that equipment and much more available when I retired in 1996.
Guess I am also interested in some of that Antenna land.

Guess I will wait for more of those 'sun spots':-)
neal/n6nw

;l --- In Elecraft_K3@yahoogroups.com, "bill_w4zv" <w0zv@...> wrote:


--- In Elecraft_K3@yahoogroups.com, "neal" <nealwh@> wrote:

Or just order all of the filters, five in each of the two receivers
and run your own evaluations. A true metrologist....Since I have no
antennas I could afford that option.
You'll need ~$1100 for the filters plus two HP 8640B Signal
Generators, a couple of precision attenuators, a hybrid combiner and a
True-RMS responding meter (and some other bits and pieces).

Where I live you could buy several acres for that amount and put up
some decent antennas! :-)

73, Bill