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Techni-Tool is a distributor of electronic production tools, oscilloscopes, multimeters, power supplies, cases, tool kits, cutters, wrenches, crimpers, solder desolder stations, BGA, microscopes, lamps, static control, workstations, chairs, torque screwdrivers, tweezers, dusters, chemicals.

Solar panel manufacturer based in Belgium

TenTec Receiver RX 320 D Review by DF9CY

Collection of several Crystal Radio receiver circuits with schematics diagrams and pictures

Report on tests done on VHF Radios to understand which are best suited for 144 MHz operation in large signal environments like VHF contests

Q15X25 is a packet modem with a KISS/AX.25 interface designed for HF transmission of AX.25 packets and TCP/IP using Automatic Repeat reQuest (ARQ) and forward error correction (FEC).

A resource for Collectors and Restorers of Vintage Electronic Equipment.

How to construct a Sniffer for 2m band

Building a Double Extended Zepp Antenna

PACTOR can be viewed as a combination of two earlier digital modes, packet radio and AMateur Teleprinting Over Radio (AMTOR). PACTOR provides improved throughput because its transmission speed adapts to the quality of the link and it uses Huffman compressed characters.

Sommerkamp FT 250 Shortwave Transceiver (YAESU FT 200)

A nice tutorial and the basics of the software defined radio, SDR, and links of software defined radios to JTRS, and general SDR receiver technology.

A look behind the scenes, learn how the ARRL laboratory evaluates new products, and what all those numbers mean to you by WA1SVF

PACTOR-II is a fully backward-compatible improvement to the original PACTOR system. It is an adaptive mode that applies different modulation and encoding methods depending on the channel quality.

A Six element antenna for the 50 MHz Amateur Radio Band v4 by DF9CY

Explains the fundamental principles of Software Defined Radio (SDR) and Digital Signal Processing (DSP) within the amateur radio context, serving as an initial entry point for hams interested in these technologies. It covers the architectural shift from traditional analog hardware to software-centric radio systems, detailing how digital signal processing algorithms are applied to modulate, demodulate, and filter radio signals. The resource compiles a list of external links to _white papers_ and project pages, offering further technical depth. This page provides a foundational understanding of SDR/DSP, enabling operators to grasp concepts like direct sampling and quadrature mixing. It references various projects and discussions, allowing users to explore practical implementations and theoretical underpinnings. The curated links direct users to resources that might cover specific SDR hardware platforms or software applications, facilitating deeper research into the subject.

This site is dedicated to design and analysis of micro- and millimeter wave filters from 0.5 to above 100 GHz.

Solar Flux, Geomagnetic Activity indexes and interpreting their relation

Vapex Tech offers over **150 different battery products** tailored for diverse applications, including specific models for Icom, Kenwood, and Yaesu handheld transceivers. The product catalog details specifications for NiMH, LiPo, and LiFePO4 chemistries, providing crucial data on voltage, capacity, and discharge rates. Customers can browse by application, such as _Airsoft Batteries_ or _Model Control Batteries_, or directly by consumer battery types like AA and AAA cells. The resource presents a structured e-commerce platform where users can filter products by category, view detailed item descriptions, and proceed with online purchases. Each product listing includes high-resolution images and key technical parameters, enabling informed selection for specific radio equipment. Operational hours are clearly stated as 9am-5pm Mon-Fri and 9am-12pm Sat, with contact information including a sales email and phone number for direct inquiries. The site also features a "Latest News" section, indicating ongoing updates regarding product availability or company information.

JT44: New Digital Mode for Weak Signals

The MT-63 modem, constructed around a high speed DSP processor, either in a dedicated external DSP unit like the Motorola EVM, or in PC software using the PC sound card, transmits 64 tones spaced 15.625 Hz apart, in the 1 kHz bandwidth.

Fine tuning your Multiband Hustler Vertical

The BTech DMR-6X2 dual-band DMR handheld radio is thoroughly reviewed, detailing its features and performance for amateur radio operators. This resource covers the radio's capabilities for both VHF and UHF frequencies, supporting Tier II DMR digital and FM analog modes. It highlights key specifications such as its **136-174 MHz** and **400-480 MHz** frequency ranges, CTCSS/DCS, DTMF, 2-TONE, and 5-TONE signaling, and its _digital simplex repeater_ function. The review provides a comprehensive unboxing experience, listing included accessories like two Li-Ion batteries (2100 and 3100 mAh), a programming cable, and a 37-page English user guide. It also specifies the radio's physical dimensions of 5.1 x 2.4 x 1.5 inches and weights of 9.9 oz with the 2100 mAh battery and 10.8 oz with the 3100 mAh battery, offering practical insights for hams considering this transceiver.

Resources for custom battery chargers and power supplies from powerstream

DF9CY using Softrock RTX on 50 MHz

The CES Wireless Technologies website details a range of **GPS fleet tracking** solutions designed for mobile information systems. It highlights offerings such as dispatch and mapping software, Automatic Vehicle Location (AVL) systems, and mobile data display terminals. The platform also mentions support for Automatic Number Identification (ANI) and Continuous Tone-Coded Squelch System (CTCSS) functionalities, indicating integration with two-way radio communication protocols. Specific products include GPS tracking devices and associated software for fleet management, emphasizing features like real-time location monitoring and operational efficiency. The site positions itself as a manufacturer in this specialized domain, catering to commercial and public safety sectors requiring robust mobile data solutions. While the page title mentions "Ham Radio Directory" categories, the content primarily focuses on commercial GPS and fleet management technologies, not amateur radio applications. The listed products are geared towards professional mobile radio (PMR) environments rather than typical ham radio operations.

VHF Broadcast Passband Filter (88 108 MHz) by DF9CY

HF Radio Preselectors,BCB filters,Low Pass filters,Band Pass filter

A 10.4-meter diameter, submillimeter spectrum telescope. Situated at the top of Mauna Kea, Big island, Hawaii.

A review of all possible receiving antennas for top band 160 meters

Passive Band-Pass Filter, low-pass filter calculator

Christoph Petermann DF9CY DRM demonstration receiver project including Circuit Diagram and component list

Solar activity can aid or hamper HF propagation beyond line-of-sight range, WA1SVF and N6BV answers to questions about Sun influence on radio signals propagation

Building the UHF Cheap Yagi for Satellite Communication

Coil Q Measurements - With a special focus on wet coils.

Known Affectionately as the "GreenbrookRepeater"!

The Vacuum Tube FAQ by Henry Pasternack

G-TOR is a trademark of Kantronics, Inc. G-TOR (Golay-Teleprinting Over Radio) can be viewed, in part, as a variant of the Automatic Link Establishment (ALE) protocol, outlined in MIL-STD-188-141A.

Mobile RFI, often manifesting as persistent noise in the receiver even with the antenna disconnected, frequently originates from the vehicle's power supply system. This guide details systematic troubleshooting steps, beginning with isolating the radio from the car's 12-volt supply to confirm the power system as the noise source. It emphasizes the critical importance of drawing power directly from the battery using **heavy gauge wire**, bypassing the fuse block to leverage the battery's natural capacitance for RFI suppression and ensuring a solid RF ground. Proper routing of power lines through the firewall is also covered, advocating for dedicated grommeted holes to prevent inductive coupling from other wiring harnesses. The article stresses the necessity of fusing both positive and negative leads from the battery, a crucial safety measure to prevent damage to the rig and mitigate high-current risks should the battery's engine block ground become compromised during service. Addressing **alternator whine**, a common high-pitched noise that varies with engine speed, the resource suggests checking battery connections and the alternator-to-battery harness for looseness or corrosion. It also mentions the utility of adding an external RF noise suppression capacitor in parallel with the alternator's internal capacitor for enhanced filtering, and the effectiveness of commercially available in-line power supply filters.

Gage applied technologies designs and manufactures high-speed data acquisition systems, high-speed digitizers in pci / cpci / pxi or pc oscilloscopes, providing utmost measurement fidelity for high frequency signals.

A Short Guide to Harmonic Filters for QRP Transmitter Output. - George Dobbs G3RJV

Maxdao: offer you 7/16, N coaxial connectors, jumper cables, feeder clamps and grouding kits, surge arresters & brackets, wall entries and microwave components used in base tower, power dividers, couplers

A collection of ad Hoc empirical comments on VHF radio waves propagation by Pete Heins N6ZE

160 to 40 meters inverted L antennas projects

DF9CY Softrock RXTX Software Defined Radio Transceiver (SDR)

Plans for building your own 3-element beam for use on 6m.

Improving your own signal quality by GM3SEK

Makers of the The Polar Explorer transmitter, which operates on 9 HF bands from 160 through 10 meters and is capable of 500 watt peak output power on SSB, CW, AM, FM and RTTY. It is intended to be used in conjunction with a transceiver.

Softrock Version 6.1 Software Defined Radio experience and modifications by DF9CY

Fundamentals of operating on single sideband