Search results

The Ameritron AL-1200 Amplifier is in current production. In its factory configuration it uses a single 3CX1200A7 (triode) tube, grounded grid configuration. Re-tubing the AL-1200 with a GS-35b with success.

Icom IC-9100 on youtube

A project for a balcony antenna that works on 7 10 14 MHz made by 2 PVC tubes coiled with insulated copper wire, a solution for restricted lots.

A rotating HexBeam antenna video from F5NZY in Paris France

Circuits, pictures and data about toroids, tubes and home made power amplifiers

Based in San Diego CA, collectible radios, test equipment, tubes, antique radio parts, speakers and kits

Video, how to build a 130 Watt Dummy Load for HF amateur radio

Helical antennas invented by John Kraus give a circular polarized wave. They are one of the easiest to design. Find a tube with a circumference equal to one wavelength, and wrap wire in a helix spaced a quarter wavelengt

A great source for hard to find HI END & power tubes & sockets, various capacitors, vacuum relays, various keys and paddles.

Sales tubes for amplifiers like GS-23B,GS-31B,GS-35B,GU-34B,GU-43B,GU-74B,GU-84B. Include links to aplifier homebrew projects

This database contains data on thousands of tubes

A three tube regenerodyne receiver by Gary Johanson, WD4NKA

Specializes in antique radio schematics and capacitors. carries antique radio schematic diagrams and electronic circuit service information for american, canadian and european antique radios.

HD Communications Corp specializes in **RF and microwave amplifiers** engineered for demanding communication, defense, and industrial applications. Their product line includes precision-built, high-power solutions, along with RF connectors, filters, HF cables, and various accessories. The company also supplies tower hardware, valves, and tubes, catering to a broad spectrum of radio frequency infrastructure needs. Beyond amplifiers, HD Communications offers a range of **RF filters**, including low-pass filters, antenna filters, and solutions for RFI/TVI mitigation. Their inventory encompasses essential components like coaxial cable and various connector types, supporting both amateur radio and professional installations. The company operates as a manufacturer and vendor, providing direct sales of its specialized RF products.

A _Topfkreis_ antenna, also known as a "bicycle pump" antenna, is presented as a simple vertical design for the 70 cm band. This variant of the J-pole antenna is notable for not requiring a ground plane, simplifying deployment. The construction details specify using aluminum tubing for the radiating element, with precise measurements for the quarter-wavelength outer tube (32 mm diameter) and the three-quarter wavelength inner sliding tubes (10 mm and 8 mm). Feeding is via a 50-ohm coaxial cable connected 90 mm from the base of the central tube. This design can achieve a gain of **4 to 6 dB** when properly tuned using the adjustable radiating element. The article details the fabrication of a critical aluminum washer, suggesting a method using a hole saw and a drill press as a lathe for precise adjustment. The illustrated example is specifically for the 70-centimeter band, and the author, Pop, clarifies construction points in the comments, including material choices and assembly techniques, ensuring a robust build for VHF/UHF operation.

Operational testing of a 10.07-meter portable HF vertical antenna, constructed from telescoping aluminum tubing (36, 32, 22, 17 mm diameters), yielded SWR measurements below 1.5 across multiple bands. Initial trials on 14.150 MHz showed an SWR of 1.6, while 7.075 MHz was problematic. Subsequent adjustments, including a 13 cm extension to the radiating element, improved performance, enabling operation on 6, 15, and 40 meters without a balun, and adding 12 meters with a balun. The design prioritizes portability, allowing transport in a standard vehicle and single-person deployment. Four 10.07-meter radials are connected at the base to enhance ground plane effectiveness. The article details the mechanical assembly, including custom adapters for tube transitions and a PVC sanitary tube sleeve for base insulation, ensuring robust field deployment. Final SWR measurements, documented with an _MFJ-259_ antenna analyzer, confirm operational ranges: 6.800-7.500 MHz (SWR < 1.5), 20.800-22.500 MHz (SWR < 1.5), and 48.800-51.500 MHz (SWR < 1.5) without a balun. With a balun, the antenna achieved SWR < 1.5 on 13.750-15.000 MHz and 24.890-28.350 MHz, demonstrating its versatility for portable _DXpeditions_.

Presents a detailed construction guide for a **Quadrifilar Helix Antenna** (QHA) optimized for 137 MHz, specifically for receiving weather satellite transmissions. The resource outlines the author's experience building previous QHA designs, highlighting challenges with tuning and nulls, and then focuses on a refined design by John Boyer, documented by Steve Blackmore, which proved easier to build and yielded superior reception. The guide provides precise element dimensions, including 1.5m of 32mm PVC pipe for the mast and 8mm soft copper tubing for the helix elements. It specifies lengths for horizontal tubes (190mm, 90mm) and helix elements (903mm, 1002mm), along with instructions for drilling, assembly, and forming a **balun** by wrapping RG58 coax around the mast. The text emphasizes critical steps like ensuring elements are square and twisting in the correct direction to avoid phase issues. It includes references to original QST articles by Buck Ruperto (W3KH) and the WxSat program for decoding satellite transmissions, contextualizing the antenna's purpose. The article concludes with a sample NOAA 12 image from September 1998, demonstrating the antenna's reception capabilities.

This article describes a loop usable from 7 - 21 mHz, using half inch copper tube 3 feet in circumference

BIRD RF power measuring, new and used, HENRY RF power amplifiers (used HF amps), TOHTSU coaxial relays, SAMLEX power supplies, RFI chokes reduce interference, Parts parts, tubes, Used amplifiers, radios, antennas and accessories, Los Angeles, CA.

VHF UHF Amateur radio antenna and antenna parts, accessories for homebrewers, antenna kits, tubes, antenna masts, antenna tripores, insulators, power amplifier mosfet, power splitters by I0JXX

A 2 meter antenna made of copper tubes, offering circular polarization

We sell antique radio tubes and antique tube radios We have over a thousand different radio tubes in stock. We also have a large stock of globe tubes.

Videos by W7NWH including D-STAR system demos

Electron tubes and vacuum tubes for industry

jpole 2mtr 70cms homebrew antenna

Scans of original G2DAF articles on his HF linear amplifier using QY3-125 tube

Building a PEP Power circuit for all analogue watt-meter

DK7ZB- Moxons with Aluminium Tubes, plans for moxon antenna for 6 10 12 15 meters

The Old Tube Radio Network is dedicated to those real, American-Made, Old Tube CB Radios

International Components Corporation has an extensive range of electronic components consisting of audible signal devices, speakers, microphones, capacitors, electron tubes, connectors, and accessories designed in recognition of the diversity of applications and special characteristics encountered by designers in today's complex world.

Antique Radio Schematics and Service Manuals for Tube Radios

Ameritron Al-811H Tuning for Power/Dissipation/Linearity, and More Generally 811A Tube Amps in Grounded Grid

An RF power Amplifier for HF bands with 3 GI-7B tubes by CT1FMS

Testing the tv reception mod for the us version. tv reception was disabled on the us version because of the possibility of it being used while driving.

Videos of AO-51 operations. Randy K7AGE has produced a number of practical and useful videos including good info on a minimal antenna setup for AO-51 reception.

The Collins TRC-75 autotune linear amplifier, owned by JF2SVU, is presented with a focus on its internal modifications. This QRO amplifier utilizes three 4CX250 tubes in parallel for its final stage, delivering 1 KW output power. Notably, the amplifier achieves full power with only 100 mW of RF input, a characteristic often associated with Collins designs. The original 400 Hz power supply has been converted for easier shack integration, and the entire RF and power supply sections have been rehoused into a compact, clean enclosure. The control unit, positioned above the amplifier, features three meters for individual vacuum tube IP monitoring and a multi-meter on the right. A dedicated 7 MHz receiver, recently completed, is also part of this integrated system. The autotune functionality means the main amplifier unit only requires connections for power, control, and coaxial cables, simplifying its operation. Key components like the 4CX250 tubes and NF capacitors are visible, along with the gearing mechanism for the final tank circuit. A timer and relay system manages high-voltage delay and cooling fan off-delay, although the cooling fan's airflow is noted as somewhat insufficient. A central volume control, which experienced a contact issue, is also highlighted.

This homemade tube oscilloscope is based on the WaterMan Pocket-Scope 0510A, a 3 tube oscilloscope made in 1946.

YY5PER video of a Icom IC-7000 modified for TV reception

How the tube converts DC to RF Power

Hellschreiber is an interesting ham radio mode developed back in the 20s. It is a bit strange and different, but fun. I'll explain what it is, then I make a couple contacts during the Hellschreiber contest.

Part 2 - Ten-Tec Jupiter CW copying and keyboard transmit

Yaesu VX-2R mini review in spanish. Watch a VX-2 in action video by YouTube

This article examines the performance of the Ameritron AL-811H amplifier with the supplied 811A tubes and with 572B tubes, and details a procedure for replacement of existing tubes.

How Vacuum Tubes Really Work. Vacuum tubes rely on hot cathodes emitting electrons and a plate attracting them to create current. A grid in between controls the current flow, enabling amplification. This article explores the nitty-gritty of how it works, including how cathode type, temperature, and electrode spacing affect the process. It explains the physics behind electron emission, space charge, and amplification factor, offering a deeper understanding than the basic principles.

Specializing in antique, vintage and tube radio repair, all makes. Transistor radio repair- from the 50's to the present. Free estimates.

In this youtube video G8GKC M0KKW and 2E0IAJ from Icom UK give a global overview of the ICOM IC-7300 HF 50 70MHz Software Defined Radio transceiver

40 meters band 5 watts transmitter, uses a 6L6 with a 6X5 rectifier and a 0D3 voltage regulator tube on the screen.

Distributor of extruded aluminum alloy tubes & tubing

Ameritron AL80B AL811H AL572 Amplifier Trouble Shooting. Tubes replacement, resistor changes.

Hobby kits and electronics, semiconductors, components, batteries, ham radio gear and more. The store sells a variety of electronic components including resistors, capacitors, and fuses. They also sell tools such as screw connectors and box cutters. Some of the featured items on the website are Nixie tube clock kits and battery holders.