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Testing the Icom IC-7700 on the mediumwave broadcast reception by VA7OJ

Station information, Morse CW information, antenna photos

Duoband Yagi 2m/70cm with 4 Elements on 2 m and 5 Elements on 70 cm and one Feed point. The 4-El.-Ultralight-Yagi for 2m can be used on 70cm with an SWR of 1,5 without any changes.

A ham radio home made preamplifier for 50 MHz and 70 MHz bands

An home madek Audio CW Filter made simply using SMD Components

Book on CW paddles, history of keyers, keyboards, oscillators, and all things related to automatic Morse code.

Echelford amateur radio society is based in ashford, middlesex, uk. has about 80 members.

This will show you how to add a RF power amplifier to your Proxim Symphony for under $50. The cost is reduced by using the existing components on the Symphony, such as the PIN diode switch, and just inserting a higher power final amplifier. Increase the RF output power of your wireless network card to 1 Watt.

S.C.A.R.T is a club based in the Southampton area of the UK open to everybody who is interested in amateur television and video related subjects.

University of Bristol Amateur Radio Society

A simple and effective sleeve type balun is easily built. This Balun can be adapted to any band. While the dimensions are not critical ( +/- 10%), it is still basically a mono band device

A 50 MHz stable and small power amplifier, suitable for portable and domestic use. This RF Power amplifier delivers 900W with used pair of tubes primary installed into amplifier.

This is an open repeater for everyone to use. Auburn Hills, MI

Doing the MARS Mod on the TS890S. This will take care of any of your HF or Mars needs, and any new bands added in the future. You will now have the new 60m Band also. It is unclear if it will open up the 4m Band that some EU Countries are now allowed.

Association of NC State University alumni who are amateur radio operators.

This is a simple 2.4 GHz SWR meter which is based around surplus microwave hardware which can be easily found. The main component is a MECA -20/-20 dB Directional Coupler which has a frequency range of approximately 700 MHz to 2.5 GHz.

Antenna most often used by Hams around the world. Inexpensive, effective and easy to build, what more could anyone ask for in a home made antenna.

Review of the excellent ICOM IC-R8600 Wide Band SDR communications receiver. Featuring Direct Sampling SDR below 30 MHz Hybrid Superhet / SDR above 30 MHz.

Torbay Amateur Television and Microwave Group GB3TB 23cms Repeater at IO8ØFL

This multiband transverter project features power output at 13,8V 50MHz 15W, 70MHz 10W, second harmonic < 65dBc. Single N connector of antenna, suitable for a dual band Yagi. Article include Block Diagram for Dual Transverter and low pass filters

This stacking offers a well known simple phasing technique. All elements can be fed in parallel by open wires provided that they are fed in phase. This can be achieved by twisting the open wire phasing-lines at 180 degrees.

The Icom IC-7700 spectrum scope feature a minimum resolution bandwidth of just 100 Hz and provide also an accurate vertical amplitude tracking permitting to use the 7700 as a bench spectrum analyser.

Risca and District Amateur Radio Society Tredegar Terrace Risca Nr Newport

Mounting on roof at the right ground level can greately impact on antenna performances because will affect the radiated angle of energy.

The author has build the Hermes-Lite SDR v1 and v2 versions describing with a very accurated text and picture the process. Additionally has documented measurements for each component

This is some general information about the lowell amateur radio club!

The DK7ZB-Dualband-Moxon-Beam provides a compact, high-performance antenna solution for 28 MHz and 50 MHz operations, utilizing a single 50-ohm feedpoint. This design functions as a mini-beam on 10 meters, achieving a gain of **4.0 dBd** with a front-to-back ratio of _30 dB_, while operating as a 2-element Yagi on 6 meters, yielding a gain of **4.3 dBd** and an 11 dB F/B ratio. The antenna's dimensions are approximately two-thirds that of a full-size 10-meter beam, making it suitable for smaller spaces. Construction details include a parts list specifying aluminum tubes of various diameters and lengths for the reflector and radiator elements. Builders like Aleks (S54S) and Marcio (PY2OK) have successfully replicated the design, with Aleks noting the utility of bending corners during assembly. Fine-tuning is accomplished by adjusting the length of specific elements that slide into larger tubes. The feeding system incorporates a balun, with options for either 300 watts using RG188 on an FT140-43 core or 1 kilowatt using _Aircell-5_ on an FT240-43 core, ensuring versatility for different power levels.

This web page is part of a self-help program for licensed amateur radio operators and radio pirates.

Dominica Island 2011 by DL7JAN

G0TRG - Trafford England

Operating within the low-frequency spectrum, transformers serve critical roles in antenna systems, particularly for 160m applications. The resource details the construction and performance of 1:1 transformers built on BN-73-202 cores, emphasizing their use as hybrid combiners or phase inverters for RX antenna arrays. Measurements reveal that these transformers exhibit minimal losses, around 0.12 dB at 1.8 MHz, with variations based on wire type and number of turns. The analysis includes comparative data on transformer performance, highlighting the impact of different winding techniques on frequency response. Notably, the use of coaxial cable for winding improves bandwidth while maintaining low-frequency efficiency. The resource also discusses braid breaker transformers, which minimize inter-winding capacitance, achieving low losses around 0.21 dB at 1.8 MHz. These insights are crucial for optimizing low-band antenna systems, allowing operators to make informed decisions regarding transformer design and implementation.

A list of links on Crystal Radio projects and related reources

Modification to an old cellular phone base station modules, with a fairly reduced output power (10 watts or so), the stock power amplifier modules will cover the 2.3 GHz and 2.4 GHz amateur radio bands.

The club is based in the Newhey area of Rochdale in North West England at the Ellenroad Steam Museum.

The Bishop Auckland Radio Amateur Club

Home made 40 meter transceiver project. The receiver is a Progressive Receiver with a few modifications. The Transmitter is a modified MFJ Cub circuit. Includes schematic and circuit diagrams for Receive Input Filter, 3-Pole 500 Hz Cohn Filter and 7 MHz Double Tuned Bandpass Filter

Common-mode chokes are useful solutions for RFI reduction. Winding a few turns of coaxial cable on the FT 240-31 toroid can reduced the noise below the received noise floor. In this article author measure different chokes

A SSTV interfsace (soundcard) to minimize RF feed back and a soundcard limiter to prevent over driving the soundcard

Icom IC-R9500 Professional Receiver with 5 roofing filters, 48 kHz DSP

Sint Maarten by K1GI (PJ7I) 7L4DXT (PJ7XK) - 18 to 24 Nov 2012

A home mande spectrum analyzer project with several pictures and disposition of components boards based on a project by S57C

Elkhorn Valley Amateur Radio Club Norfolk

This page describes a printed circuit board that you may use to build a QRP keyer.

Presents two distinct hardware modifications for the Icom IC-7300 transceiver, detailing the necessary steps for each. The first modification, a _MARS_ transmit expansion, involves the physical removal of specific surface-mount diodes (D422) from the main board, enabling transmit capabilities across a broader frequency range, including out-of-band frequencies. It specifies the diode location on US versions of the IC-7300 and suggests using small diagonal cutters if a soldering iron is not preferred or available. The second modification focuses on the internal antenna tuner, aiming to provide wider impedance matching capabilities. This involves adding a **100k ohm** resistor to a designated point within the tuner circuit. The resource also briefly mentions a microphone modification for the _HM219_ and a general power increase, though without specific instructions for the latter two. It emphasizes safety precautions, such as disconnecting power and inspecting the work area.

This page includes an interesting and comprehensive review of the ICOM IC-7300 SDR HF / 50 MHz transceiver. The author focuses on many aspects of this transceiver with impressions based on his experience

The "Beginner’s Guide to Small-station EME" by Paul Bock, K4MSG, offers an insightful look into Earth-Moon-Earth communication, a fascinating aspect of VHF and above amateur radio. This presentation demystifies moonbounce, explaining how two-way radio contacts are made by reflecting signals off the Moon. K4MSG highlights the historical context of EME, noting the substantial investment and technical challenges that once characterized these operations, often requiring setups like the W5UN "Mighty Big Array" (MBA). Historically, path loss exceeding 250 dB, spatial polarization offset, Faraday rotation, and galactic noise made EME a formidable pursuit, with CW being the mode of choice for signals that had to be audibly detectable. Equipment limitations in noise figure and coax performance further compounded the difficulty for early moonbouncers. However, the landscape of amateur EME dramatically shifted around 2003 with the introduction of the JT65 software. This innovation, specifically designed for EME, allowed for signal decoding well below the noise floor, making small-station EME a practical reality for more hams using common transceivers and less complex antenna systems.

DL7AFS, Babs and DJ7ZG 5-19 November 2012

Review of the ICOM IC-R9500 Wide Band DSP Receiver

Departamento de Radio Escutismo do Nucleo Moinhos de Vento Portugal