Search results
Query: 70 MHz
Links: 143 | Categories: 4
-
-
5-element antenna, with which G0JJL has worked lots of EU crossband, and won the RSGB Christmas Cumulatives 70MHz section twice in a row. -
A 5 elements homemade DK7ZB yagi antenna for 4 meters band based on a 50MHz TONNA -
-
This PDF document details the construction of a **70 MHz** Big Wheel antenna, a horizontally polarized omnidirectional array. The design utilizes three full-wave loops, each approximately **2160 mm** in diameter, arranged in a triangular configuration. The resource provides mechanical dimensions for the antenna elements and a comprehensive bill of materials, specifying component quantities and types, such as M8 stainless steel bolts, 15x15x1.5 mm square aluminum tubing for spacers, and 8 mm aluminum rod for the arcs. The central hub is constructed from two 160x160x8 mm aluminum plates, with four 40 mm long polyamide insulators supporting the radiating elements. The feed system incorporates a 50 mm diameter aluminum pipe for mounting and a matching stub constructed from a 120x20x2 mm aluminum sheet, connected via M8x10 mm bolts. The resource includes a diagram illustrating the mechanical dimensions and assembly points, including the N-connector fixing point and the center conductor attachment. The project was published on May 25, 2011, by Peter OE5MPL and Rudi OE5VRL. DXZone Focus: PDF | 70 MHz Big Wheel | Mechanical Dimensions | **2160 mm** loop diameter -
-
The antenna described here is a direct-connect dual-rectangle beam for use on 70 cm between 440 and 450 MHz -
Over 100 amateur radio beacon audio files are presented, offering a direct auditory experience of propagation conditions across a wide spectrum of frequencies, from 1.8 MHz to 47 GHz. These recordings, primarily captured by IW3FZQ and IK3NWX, document signals from beacons such as DK0WCY, IY4M, GB3RAL, and S55ZRS, providing a valuable resource for **propagation study** and **beacon monitoring**. Each entry in the list specifies the beacon's callsign, its operating frequency in kHz, and the recording operator. This compilation includes signals from beacons located in various grid squares like JN55VF, JO44VQ, and IO91IN, illustrating diverse geographical origins. The frequencies covered span the 160m, 80m, 40m, 30m, 20m, 17m, 15m, 12m, 10m, 6m, 4m, 2m, 70cm, 23cm, 6cm, 3cm, 1.2cm, and 6mm amateur bands. Users can listen to these recordings to identify characteristic beacon tones and observe signal strength variations. The resource also invites other radio amateurs to contribute their own beacon audio files, fostering a collaborative archive of propagation data. The last update to this collection was on March 24, 2009, indicating a historical snapshot of beacon activity. Accessing the files requires the Real Player software. -
This web article by VK3BLG details the construction of an experimental 70cm (432 MHz) circularly polarized patch antenna, intended for satellite communication. The resource provides dimensions, feed point specifications, and impedance matching considerations for a single patch element, with discussion extending to array configurations for circular polarization. Construction involves a copper patch element on a dielectric substrate, fed via a coaxial cable. The design is based on information derived from AO-40 satellite antenna specifications, focusing on achieving circular polarization for satellite reception. The article includes specific dimensions for the patch and feed points, along with impedance values. Validation is implied through on-air satellite reception reports, with initial signal reports of **1 S-point above noise** for AO-40 beacons using a grid reflector, improving to **3-4 S-points above noise** with a 2-turn helical feed. The author references a _NanoVNA_ for impedance measurements and discusses the relationship between slot and dipole antennas in the context of patch design. DXZone Focus: Web Article | 70cm Patch Antenna | On-Air Satellite Reception | Circular Polarization -
70 MHz transverter, 4m band, by G3XBM -
This circuit enables fair copy of strong 444 MHz signals, off a local repeater, using a 2m rig and a 1/4λ 70 cm indoor ground plane antenna. -
-
A view on TS570 sensitivity, a plot from 1.8 MHz to 60 MHz -
5 Element Yagi with Conventional Driver, this little Yagi has a high F/B, which makes it quite useful as a contest stack. -
An home made low pass filter for 70 MHz by IK0VAQ -
Pictures and design plan of a 28 MHz - 70 MHz transverter 3Watts in - 8Watts out by 9A2SB -
A 70 cm yagi designed for EME + SSB narrow bandwidth version, strictly G/T breeding. This little Yagi has a high F/B, which makes it quite useful as a contest stack -
The Four Metres website offer a global overview graph of the four meter band plans world wide -
A 160W linear amplifier for 4 meters band based on GI0GDP -
The Cass County Amateur Radio Club is a Non-Profit Organization serving Logansport, Indiana 46947. The CCARC participates in ARES Nets, Skywarn Nets and Field Day and has 2m repeaters at 147.18 MHz, 145.23 MHz, and 145.35 MHz and a 70cm repeater at 443.65 MHz. -
This unit uses four capacitors, only two of which are variables, and a single tapped coil. It is built in a die-cast box, and has been tested up to 80W input power on 70MHz by G4CJZ -
G8ACC article project for a 144 & 430 MHz wavemeter -
-
-
Modification and verification of the FT847 to optimize 70 MHz performance by G4FUF -
This design has the following advantages low-cost components, Easy to set-up - nothing to adjust, no metalwork required, and only four soldered joints! -
This web article details the construction of a 4-meter band coaxial dipole antenna, designed for operation between **70.000 MHz and 70.500 MHz**. The resource provides a bill of materials and step-by-step assembly instructions for a half-wave dipole constructed from _RG-58_ coaxial cable. The design specifies a direct 50 ohm feedpoint impedance, eliminating the need for an external matching network. Construction photographs illustrate the stripping and soldering processes for the coaxial cable elements, ensuring proper electrical connection and physical integrity. The article includes specific dimensions for the radiating elements, derived from calculations for the 70 MHz band. The project outlines the physical dimensions required for resonance at 70 MHz, with the outer braid forming one half and the inner conductor forming the other. The feedline connection is directly to the coaxial dipole's center, maintaining a 50 ohm characteristic impedance. While the article does not present SWR plots or VNA sweeps, it focuses on the mechanical construction and dimensional accuracy for achieving a functional 4-meter dipole. The design is intended for fixed station use, with no specific mention of polarization or height above ground, but implies a standard horizontal orientation for dipole operation. DXZone Focus: Web Article | 4m Coaxial Dipole | Construction Guide | 50 ohm Feed -
Improving the reception on 70 MHz for the yaesu FT-847 -
Receiver performance review of the Kenwood TS-890S HF,50MHz,70MHz amateur radio transceiver by Sherwood Engineering -
Operates the VHF 2 Meter KR9RK repeater on 147.270 MHz -
Pictures, design plan and description of a 5 element yagi antenna for the 4 meters band by 9A7PJT -
-
A Yagi-Mag antenna for the 4 meters band with NEC and MMANA files plans and pictures -
-
A compact Yagi with bent Driven Element. Worlds smallest yagi that did EME QSO -
-
Amateur radio repeaters extend communication range for mobile and remote stations by retransmitting signals on a different frequency, often for emergency communications. The resource details various repeater bands, noting that 2 meters and 70 cm are primary for activity, with 10-meter repeaters offering potential national and overseas coverage. It specifies **18 channels** on 6 meters and **31 channels** on 2 meters, along with a new 70 cm offset of _7 MHz_ adopted in 2015. The content explains how repeaters can be linked via dedicated transmitters/receivers, landlines, or Internet VoIP systems like _IRLP_ and Echolink, enabling global connections. It also describes simplex gateways for multi-band operation and the use of CTCSS subaudible tones for access control and interference mitigation. The document highlights specialized repeaters for modes beyond voice, such as SSTV and ATV, particularly on 70cm and higher bands. Operational guidelines for efficient and courteous repeater use are referenced, along with links to Australian repeater listings and band plans. -
The _DL4EBY_ resource page provides operational data for Earth-Moon-Earth (EME) communications on VHF, UHF, and microwave bands. It includes a 432 MHz and above EME Directory in ASCII and HTML formats. _K1RQG_ provides 432 MHz and up EME Net Notes. EME Operating Procedures were confirmed at the EME Conference 2002 in Prague. A lunar calendar from _DL7APV_ is linked via _G4CCH_'s pages. Resources for CW contest operation include the _PED411i.zip_ file. A "Cheat Sheet 432 & up" is available for EME operations. The _Dubus_ 70cm CW EME Activity Event is referenced for moonbounce activity. DXZone Focus: Operating Activity | Global | EME, CW | VHF, UHF, Microwave -
A high G/T Yagi with bent DE for compact contest arrays -
The mod requires an INRAD 45,705 MHz Crystal Roofing filter and the IC-765 add-in Board -
Get involved with 70cm Earth Moon Earth communications it is easier than you think, EME promotional Flier -
-
Sixty-meter repeaters typically use a 1 MHz frequency separation between input and output, while 2-meter repeaters commonly employ a **600 kHz** split and 70-centimeter repeaters use a **5 MHz** offset. This article details the fundamental technical principles of amateur voice repeaters, explaining how they extend VHF/UHF communication range by receiving on one frequency and simultaneously retransmitting on another. It covers essential components such as receivers, transmitters, filters, and antennas, often situated on elevated locations for optimal coverage. The resource delves into the critical challenge of _desensing_—where the repeater's strong transmit signal overpowers its own receiver—and the engineering solutions employed, including antenna separation and the use of high-Q cavity filters. It also explores various control and timing systems, from basic squelch activation to more sophisticated microcontroller-based boards that manage functions like voice identification, time-out timers, and fault protection. Different access methods are discussed, including open access, toneburst, CTCSS subtone, and DTMF, each offering distinct advantages for managing repeater usage and mitigating interference. Furthermore, the article examines repeater linking, both conventional RF methods and modern internet-based solutions, highlighting how linking expands coverage and promotes activity across multiple repeaters or bands. It introduces less common repeater types such as 'parrot' repeaters, which use a single frequency and digital voice recording, and linear translators, capable of relaying multiple signals and modes simultaneously across different bands, often found in amateur satellites. -
Icom IC-703 HF + 50 MHz transceiver, english official instruction manual available in PDF File to download. -
Description of the beacon hardware and DDS frequency source used for G4JNT personal beacon -
The prototype for this amplifier was originally designed for 70cm and was used on the 2004 3B9C Dx-pedition to Rodriguez Island for satellite and EME. It had a noise figure of 0.49dB with an associated gain of 20dB. -
A 70 MHz Transverter project with a block diagram and schematics -
-
This transverter was built in 1994 and include in this page a pdf with circuit board, and a version of this project for 70MHz. -
A comparison of commercial 4m verticals by by Ian Hogan G6TGO