[Elecraft] [K3] 700 Hz 8-Pole CW Filters (by INRAD) -- Exclusively from unpcbs.com

[Gary W. Hvizdak]

    We have shipped more than 100 of these custom INRAD filters since 2011
with an overall customer satisfaction record of 96.5%.  What's more, since
April 2012, 100% of our customers have reported being pleased with 700 Hz.

    In the interest of full disclosure, FYI these statistics don't include
customers who purchased a 700 Hz filter but never used it.  We've had four
such customers to date ...

1. Chris P. : who was reluctant to open his factory-built K3, with sub-RX.
2. Mike  R. : who reluctantly sold his K3, soon after ordering his filter.
3. Joel  C. : an SSB-only op, who ordered one on a whim for digital modes.
4. John  Z. : who ultimately purchased a Ten-Tec Omni VI, instead of a K3.


SPECIFICATIONS

  Overview
    o   Center Frequency  : 8125 kHz
    o   Nominal Bandwidth : 700 Hz
    o   6/60 Shape Factor : 1.7
    o   Insertion Loss    : 6 dB  (note 1)

  Typical Passband Response  (note 1)
    o   0.680 kHz @  -3 dB
    o   0.785 kHz @  -6 dB  (note 2)
    o   1.030 kHz @ -30 dB
    o   1.340 kHz @ -60 dB

  Center Frequency Deviation
    o   +/- 100 Hz worst-case, across all manufacturing lots  (note 3)
    o   +/- 5 Hz typical, within any given manufacturing lot  (note 4)

  Notes:
    (1) Data extrapolated from the plot of a randomly selected filter.
    (2) According to INRAD, the -6 dB bandwidth can vary by +/- 15 Hz.
    (3) To date, the standard deviation of all batch-offsets is 45 Hz.
    (4) In contrast, Elecraft considers "within 40 Hz" a matched pair.


    Visit http://www.unpcbs.com to order and for:  pricing; availability;
delivery status; terms of sale; shipping charges; passband response plot;
user comments; FAQs; app notes; a slideshow presentation illustrating and
comparing INRAD's CW bandwidth choices; and a marketing brochure that has
information not found elsewhere on our website.

73,
Gary  (Kilo India Four Golf Golf X-ray)

P.S.  In the unlikely event that you aren't delighted with 700 Hz; FYI on
average, these special-order filters retain 95% of their original selling
price on the second-hand market.