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4S-High Pass Filter
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4S High Pass Filter
Designed by
David Cripe NMØS

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and Information Group
4SQRP
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Kitted and Offered For Sale By The Four State QRP Group        

NEW!

 
Featuring the famous NMØS Spiral coils, it is a None Simpler design, as seen in the Bayou Jumper and Cricket transceivers. This innovative and highly effective High Pass Filter (HPF) is a must have for experimenters. The kit includes all the components to finish the build, including a beautiful jet black PCB enclosure - another NM0S trademark. At 2"x2"x3" it will fit easily on your operating desk or workbench. See the specifications below for performance data.
Simple direct conversion transceivers frequently suffer from overload by nearby AM broadcast transmitters, causing their signals to leak through into the received audio. So if you live close to an AM station and have been frustrated by interference, this is the perfect filter project for you. NOTE: this isn't a QRP only design. Because of the high quality components, you can install behind your 100W QRO rig.

Specifications and Design Features
    Beautiful jet black silk screened and easy building PCB enclosure.
    70 dB attenuation of frequencies below 1.6 MHz
    Cut off frequency <3.4 MHz.
    Maximum Power Throughput: Tested at 100W.
    Impedance: 50 ohms
    Extremely low insertion loss: 1 dB or less over pass band
    Enclosure Size: 2"x2"x3".
    NO TOROIDS to wind. Spiral coil inducors are etched on pcb's.
Documentation
    Assembly Manual
    Response Curves
    Schematic
    Parts List
    Photopage
    Electronics 2000's Excellent Capacitor Identification Page  Posted with permission.
    Electronics 2000's Excellent Resistor Code Graphic Calculator  Posted with permission.
Ordering Information:
The cost of this kit is $25, shipping is additional. The Paypal buttons below include the shipping costs. Shipping will be via USPS Priority Mail with a tracking number.
Pay With PAYPAL
Choose US or DX Order
        Official PayPal Seal
If paying by check or money order (US dollars only) please make it out to "Four State QRP Group" and send to:
Four State QRP Group
Tom Brown WØMFQ
PO Box 627
St. Charles, MO 63302

NOTE TO CANADIAN PURCHASERS:
Due to high bank processing fees, we can no longer accept Canadian Money Orders.


The 4S-HPF is carefully kitted and shipped by Walter Dufrain K5EST
Please direct shipment related questions to Walter

All proceeds are applied toward funding OzarkCon.   Thank you for supporting The Four State QRP Group.

 
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