[Elecraft] Inrad 1.5 KHz filter for K3

[Ed Muns]

K6LL posted:
> I was visiting the Inrad Web site this morning and noticed 
> the following:
> 
> Narrow SSB Filter for Elecraft K-3
> By special request we have made a small run of super-narrow 
> 1500 Hz SSB filters for the Elecraft K3. We are shipping from 
> stock. (Dec 10, 2008)
> 
> 1500 Hz 8215 kHz SSB 8-pole crystal filter Bandwidth 1500 Hz 
> Center Frequency 8215.0 kHz Mode SSB Typical Insertion Loss < 6 dB
> Price: $125.00
> 
> http://www.inrad.net/inrad.php?mode=announce

I have been using these crystal filters in my K3s and KRX3s for 8 months
now.  The actual bandwidth is about 1650 Hz and I configure my receivers to
engage them at DSP bandwidths of 1500 Hz and lower.  Nearly all my SSB
operating is contesting and my preferred SSB operating bandwidth is 1500 Hz
(300-1800 Hz).  These crystal filters give a bit tighter DSP protection than
the 1.8 kHz crystal filters (which are actually about 1.9 kHz at the -6 dB
points).  I can't seriously argue that 250 Hz narrower first IF filters are
a substantial improvement, but they offer another alternative for picky
contesters and DXers!  Even if you operate at a DSP bandwidth of 1500 Hz,
the 1.8 kHz crystal filters are outstanding.

Secondarily, these filters offer DSP protection for CW bandwidths wider than
the narrow CW filters, where the 1.0 kHz crystal filter is often deployed.

Ed - W0YK