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Query: 70 MHz
Links: 143 | Categories: 4
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This halo antenna for 50 MHz is made with a true Gamma Section this time and is fashioned from aluminum -
A short but efficient dipole for 40 meters band -
Homebrew VHF Yagi 50MHz 144MHz 432MHz 1296MHz 2320MHz 6M 2M 70CM 23CM 13CM Yagis -
Here is a 70cm (440 Mhz) J-Pole antenna that is inexpensive, and easy to build. Author use 1/2 inch copper pipe, and the associated fittings necessary. The dimensions aren't typical however, this is what it took to get its SWR low. -
Build your own antenna for the 23cm band ( 1250Mhz - 1280Mc ) using some aluminium and this simple design. -
This project details three variants of a vertical half-wave antenna design for the 4-meter (70MHz) amateur radio band. The antennas use end-feeding with a parallel-tuned circuit for impedance matching to 50-ohm coaxial cable. The first variant uses suspended flexible wire for portable use, the second employs a fiberglass rod with internal wire for permanent outdoor installation, and the third utilizes aluminum tent poles for quick mobile deployment. Despite the narrow bandwidth of the matching circuit, this suits the narrow 4m FM allocation well. The design offers an effective omnidirectional radiation pattern and can be constructed with readily available materials. -
The latest and best yagi beams for 432MHz tested and optimized with NEC -
This article describes the construction of a Moxon rectangle antenna for the 70MHz (4-meter) amateur radio band. This compact two-element beam design features folded element ends, reducing its width to approximately 75% of a half-wavelength. The antenna was built using enamelled copper wire stretched over a lightweight fiberglass kite spar frame, with a direct coaxial cable feed connection. Initial testing showed a VSWR of around 1.3 with distinct nulls at 90 degrees when horizontally mounted. The author later tested vertical polarization and suggested that the antenna's compact size might allow for indoor loft installation. -
Halo antenna for 4 meters band with dimensions, pictures and assembling instructions -
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The QM7 antenna is a simple 7 elements Yagi with 3.70 m boom length for the lower 144 MHz SSB/MGM band, used it mainly for Sporadic-E and MS contacts. It exhibits a forward gain of 11.35 dBd; i.e. 13.5 dB forward gain over the isotropic radiator, while the F/R is about 12.5 dB -
An AO-10 antenna by K5OE, this design is optimized for 436.8 mHz with a 50 Ohm feed -
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The K4VX linear-loaded dipole for 7 MHz, simple and practical way to make a short but efficient 40-meter dipole. -
These web receiver based in Kiew Ukraine show PSK31 activity on 20m band 14.070-14.074 MHz remotely by using a web browser. Requires java by the MixW team -
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Enables out-of-band transmit for 1.6 MHz to 54 MHz, Improved VHF recieve mod, other band expansions -
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Here is a very simple and practical way to make a short but efficient 40-meter dipole. The K4VX Linear-Loaded Dipole for 7 MHz -
Build this simple and cheap 70 MHz Exciter and start to transmit Digital Television by Jean-Francois Fourcadier -
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PA5DD version of the dual band yagi antenna for 50 and 70 Mhz -
Dutch Antenna and Tower Manufacturers from Slimline Square Triangular Round Towers. Antennas production include Yagi Monoband/Dipole/HF Quad /50MHz and 70MHz Yagi-Quad, VHF-UHF yagi-Quad and Comby antennas VHF/UHF/SHF -
A copper pipe Hentenna for 144 MHz. The Hentenna, a compact, high-gain loop antenna developed in Japan in the 1970s, offers approximately 5.1 dBd gain, comparable to a three-element Yagi. Adapted for 2 meters, it is crafted from copper pipe for simplicity, affordability, and broadband performance. Requiring no feed-point tuning, its construction involves soldering standard copper fittings. Installation demands non-conductive materials to minimize signal disruption. Versatile for vertical or horizontal polarization, it is ideal for FM, repeater, SSB, or CW applications. This design emphasizes practicality and performance for amateur radio enthusiasts -
This purpose of this page is to give a brief description of a 70 MHz transverter that has been published in the Danish amateur radio magazine "OZ" -
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Transverter for 70MHz, a project by G3XBM -
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This article describes the 144MHz horizontally polarised antenna at VK1OD in November 2008. The antenna uses two identical four element arrays that were constructed around 1970 -
Enabling IC 706 for 4 meter band modification in italian. -
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This article presents a technical investigation into spurious emissions from the Yaesu FT-847 transceiver when operating on the 70MHz (4-meter) band. The author discovered significant problems with both factory "UK spec" and modified units. Spectrum analysis revealed that when transmitting at 70.2MHz, the radio produces numerous spurious signals, with the most prominent emission at 45.6MHz measuring only 3dB below the fundamental frequency. The study also documents poor power efficiency on 4m (10.3% at 30W output) compared to 6m operation (23.5% at 30W). Tests verified that jumper configurations had no effect on filter selection. The author warns that using these radios on 4m may violate license conditions due to excessive spurious emissions. -
ACOM 1000 modification uses electric band switching, such that both 6m and 4m operation can be maintained. -
This document details the design and construction of a Vinecom 6N4 dual-band Yagi antenna for the 50MHz (6-meter) and 70MHz (4-meter) amateur radio bands. The antenna features 9 total elements (4 elements for 50MHz, 5 elements for 70MHz) on a 4.236-meter aluminum boom. Computer simulations using MMANA software predict 7.21 dBd gain on both bands with front-to-back ratios of 16.01dB (6m) and 15.37dB (4m). The design uses 12.7mm diameter elements mounted on a 32mm square boom, weighing 5.7kg total. Practical measurements with an MFJ-269 analyzer confirmed good SWR performance across both bands after element length adjustments. -
Building an omnidirectionnal antenna for the 23 cm band, 1240 - 1270 Mhz -
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A PDF presentation of a home made moxon antenna for 50 MHz 70 MHz and 144 Mhz. The project is mainly out of surplus plastic Plumbing pipes and clips etc, and also details of how the dimensions were calculated. -
The Official Web Site of the Long Island Mobile Amatuer Radio Club. The 4th largest ham radio club in the USA! We have 3 hamfests a year and repeaters on 2M, 70 CM, 220 Mhz and 1.2 Gig. -
The Quadlong antenna for the six meter band. This antenna feature a total gain of 6,4 dBd, F/B 21 dB and is also available in 70MHz version. Includes detailed pictures and plot diagrams. -
Comparison of 50 and 70 Mhz antennas, commercial and home made projects -
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 -
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EME DX Eperiences and dx news by K2UYH (W6/PA0ZN) -
This antenna is designed to be mounted off the side of a tower. Works on 136-153 Mhz range but also on 70 cm band -
There are 2 possible TX extensions on the E version, either full TX (1.705 - 30 MHz) or just open up 5 MHz (cut the R968 jumper and make it into a K version). This mod has been tested on TS 590S and not on TS 590SG -
The antenna is a VHF side is a 2m moxon, tuned on 145.825 MHz. The driven element of the moxon couples to a driven element for a 5 element 70cms Yagi, tuned on 436.5 MHz. -
The original project of a dual band yagi antenna for 50 and 70 mhz, published on dubus 2/2007 by YU7EF -
This document details the design and construction of the PA70H, a 50-watt RF amplifier for the 70MHz (4-meter) amateur radio band. Built around the Mitsubishi RD70HVF1 MOSFET transistor, the amplifier delivers 45-55W output with 3-5W input power while operating on 13.8V DC at approximately 7-8A. The PCB design incorporates multiple protection circuits including overcurrent, SWR, and temperature control. The amplifier features various control modes including GND PTT, +13.8V PTT, and RF VOX. Two versions are available: PA70HLI (requiring 100mW input with additional driver) and PA70H (for 3-5W input). The comprehensive documentation includes circuit diagrams, assembly instructions, and performance data showing successful operation from both 100mW and 3.5W input sources. -
