audio filter

Pi-filter ATU for Beams and Verticals - A ATU for beam and vertical antennas by PA0FRI

K7ICU Repeater Network in Tucson AZ - Live streaming audio of the K7ICU repeater

Murfreesboro Police and Fire Dispatch Live Scanner Audio Feed - Murfreesboro Police and Fire Dispatch Live Scanner Audio Feed on RadioReference.com

CWS Coil Winding Specialist - Manufacturer of transformers, inductors coils and chokes. Custom winding, EMI / RFI Filters, Antenna Windings on ferrite rod, Antenna Winding on phenolic. Any antenna coil designs.

HI-Z Antennas - HF receiving systems and components, band pass filters, array controllers, HI-Z pre amplifiers

Kathrein Inc - Manufacturer of professional antenna and filter systems for communications and broadcasting, serving commercial and governmental markets worldwide.

Communication Coil - Communication Coil, Inc. designs and produces custom, high reliability Filter Networks, RF Coils, Chokes, Inductors, Baluns, Toroids and Power Magnetics for communications

Taiyo Yuden - Ceramic capacitors, inductor ferrite products, high frequency dielectric components like chip antenna and filters.

Icom ACC1 interface - Need to interface both a TNC and the computer soundcard? This is a ICOM 756PRO ACC1 audio/keying/FSK interface by WA0SXV

Yaesu FT-1000D improvements - Filtering, modifications and improvements of the Yaesu FT-1000D

Yaesu FT-1000 Sub RX Filter - Filtering of the Sub RX of the Yaesu FT-1000(D)

Kits and Parts dot Com - Supplying Toroids, Electronic Parts and Kits to Engineers, Schools and Hobbyists. Capacitos, filters, inductors, qrp products

The Audio Guru - The Audio Guru sells hi quality parts and installation accessories for amateur radio on the web at www.theaudioguru.net, and at HamFests in the East Tennessee region, as well as Knoxville/Maryville Tennessee.

The AM Forum - A site dedicated for the AM Radio Amateur and vintage radio. Home of the AM Press/Exchange, The AM Forum (the largest BBS of it's kind),and The AM Classifieds, Photos, Audio, and technical information. Audio and Video chat rooms.

Fatpigdog's Real Time FFT Audio Spectrum Analyzer - Fatpigdog's Real Time FFT Audio Spectrum Analyzer. User interface has the look and Feel of an HP Spectrum Analyzer. But, in addition to the regular Spectrum Plot, it also produces detailed Waterfall plots. The user can optimize the color map, chosing from a wide assortment of color themes. This analyzer supports multiple traces, trace arithmetic and normalization.

Enhanced SSB Audio - K4QKY Presentation about SSB Audio, what's it all about and why the controversy

ESSB enhanced SSB - About SSB Audio by N4KC

Using Band-Pass Filters - Clean Up Your Signals with Band-Pass Filters

Receiver Band-Pass Filters - Third-order Cauer filters can boost performance of multi-transmitter, multi-operator contest stations to the next level. The filters are practical and you don’t need expensive test equipment to align them.

Passive CW headphone filter  ^updated - This filter is a plug in adapter that has no batteries but gives very good performance by G8MNY

The Rock-Mite CW Kit - The Rock-Mite is a 40m CW kit offered by Small Wonder Labs . It features built-in keyer, direct conversion receiver with a crystal RF bandpass filter, 500 milliwatts of power, and switchable frequency offsets to work around QRM

A Ham's Guide to RFI, Ferrites, Baluns, and Audio Interfacing - Understanding and solving RF interference problems using ferrite

Inrad Roofing Filter in the Yaesu FT-920 - Insalling Inrad roofing filter in the FT-920 with pictures and comments

Kenwood-to-PC Serial Interface - A circuit that connects an IBM® compatible personal computer, running TR Log or CT (etc.) contest logging software, and Kenwood transceivers equipped with serial control ports. CW keying is also provided in this RFI filtered interface unit.

Kenwood TH-215 TH-415 mods - Unfilter LF output from the TH215/415 kenwood portable radio