noise

193 links - and 2 categories

160m Short Vertical Loft Antenna - This is a very small vertical 160m antenna that fits in the loft of even my small house. It was built as a way of getting a signal out on 160m for local AM contacts, but the local noise level was far too high to allow it to be used at night for this purpose. However, on WSPR it did a pretty good job with WSPR spots from a very long way across Europe being received when running 2.5W out.
[ Hits: 208 | Votes: 1 | Rating: 7 ]

LFA Yagi Antenna for 6 meter band - This antenna is reported as being lower noise than conventional yagis and had a very low SWR for 500 KHz.
[ Hits: 200 | Votes: 3 | Rating: 7.33 ]

IAT Interactive Antenna Table - IAT is an excel sheet table evaluate parameters of VHF UHF antennas edited by Vladimir UR5EAZ. The difference between this tool and the existing VE7BQH Antenna Table is the use of G / T and C / N instead of the G / Ta parameter. In this table, Vladimir applies the ITU recommendations to assess the noise properties of a radio receiving system and shows the advantage of the G / T concept over the G / Ta concept when choosing an antenna.
[ Hits: 106 | Votes: 4 | Rating: 9.5 ]

Kuhne Electronic - High quality microwaves components for professional and radioamateurs. Power Amplifiers, Low Noise Amplifiers, Es hail 2 Converter Transverter, Signal Sources, Passive Components and Accessoires
[ Hits: 106 | Votes: 0 | Rating: 0 ]

Recognition of CW signs at different listening levels and frequencies - The recognition of telegraphy masked by noise at 40 and 80 signs/min telegraphy speed was studied in 10 normal-hearing subjects at different sound pressure levels (25-85 dB SPL in steps of 5 dB) as well as at different test frequencies (2000, 1000, 800, 630, 500 and 250 Hz). The ability to recognize the signs varied with varying SPL. Recognition for most of the subjects was best at an SPL close to 70 dB. All subjects improved their recognition as the frequency was lowered to 500 Hz, some even at 250 Hz. These facts should be taken into consideration when training telegraphy operators as well as in the construction of radio receivers to permit listening at low frequencies. Furthermore, the critical ratio was calculated at the different test frequencies.
[ Hits: 81 | Votes: 1 | Rating: 7 ]

Decoding Russian Meteor-M2 satellite images in real time - The Meteor-M N2 is a polar orbiting Russian weather satellite that was launched on July 8, 2014. Its main missions are weather forecasting, climate change monitoring, sea water monitoring/forecasting and space weather analysis/prediction. Meteor-M N2 transmits images using the digital LRPT protocol at around 137.1 MHz with can be received with an RTL-SDR.
[ Hits: 200 | Votes: 0 | Rating: 0 ]

ICOM IC756 Fan Modification - ICOM IC756 PRO II III, PS125 Fan Modifications, install an external cooling fan on the ICOM IC756 PROIII to minimize the heat on the chassis, then will perform a fan modification on the ICOM PS125 power supply to minimize the fan noise.
[ Hits: 115 | Votes: 1 | Rating: 10 ]

Hamtech - HAM-made engineering products supplies and produces coaxial relays, antenna switches, sequencers, roller inductors, variable capacitors, low noise preamplifiers, RF power rotary switches and coil bodies.
[ Hits: 192 | Votes: 0 | Rating: 0 ]

AI-Powered Radio Signal Cleanup: Battling QRM in Real Time - Amateur radio enthusiast Jean-Paul Suijs discusses combating manmade noise (QRM) in radio signals using AI. Detailing experiments with phase-shifting techniques and the self-learning nature of AI, he explores AI-based audio processing apps for real-time noise cancellation during radio contests, demonstrating results on both medium wave and shortwave bands.
[ Hits: 71 | Votes: 0 | Rating: 0 ]

5 Things to Know About Portable Power Stations - These pricey battery-powered devices are the only type of generator that can be used indoors safely. The article reviews pro and cons of power stations evaluating runtime, power delivery, power quality, ease of use, and noise.
[ Hits: 171 | Votes: 0 | Rating: 0 ]

23cm Low Noise Amplifier - A low noise amplifier for the 23cm band with schematic diagram picutes and instructions article.
[ Hits: 66 | Votes: 0 | Rating: 0 ]
VHF UHF Low noise Amplifiers - 2m 70cm 23cm Low noise Amplifiers, 3 Low noise amplifiers Outdoor unit with DB6NT parts completed.
[ Hits: 128 | Votes: 2 | Rating: 5 ]
A JFET preamplifer for 50 MHz - The circuit is simple, designed with a low component count and an inherent simplicity in order to keep the cost of building the preamplifier low, and to assure low noise operation.
[ Hits: 98 | Votes: 0 | Rating: 0 ]

QRM Eleminator by DC2WK - A home made project to reduce noises from lower bands, an X-Phase QRM Eliminator project that can help you a lot
[ Hits: 180 | Votes: 0 | Rating: 0 ]

Signal to Noise Ratio SNR - Signal to Noise Ratio, definition and application to Radio Communications. Signal to Noise Ratio (SNR) is a figure of merit that compares the level of a desired signal to the level of background noise.
[ Hits: 133 | Votes: 5 | Rating: 8.4 ]

Common-mode chokes Measurements - 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
[ Hits: 156 | Votes: 1 | Rating: 8 ]
Mains RF Filter - If RF noise threatens to take your hobby away, this could be probably a good solution to reduce or even eliminate RF Noise.
[ Hits: 125 | Votes: 0 | Rating: 0 ]

An introduction to YIG Tuned Oscillators - The YIG Tuned Oscillator (YTO) is the only direct signal source to provide multi octave tuning bandwidths in excess of 10 GHz. Common tuning ranges are from 2-10 GHz, 8-18 GHz and 10-20 GHz. YTO is are also known for their superior phase noise and exceptional tuning linearity.
[ Hits: 35 | Votes: 0 | Rating: 0 ]

2m to 70cm Transverter Circuit - A 70cm / 432 MHz Transverter Project transverter circuit is an electronic device that converts a radio signal from the 2 meter to the 70 centimeter band and vice versa, allowing a single transmitter/receiver to be used for both bands. It consists of an IF stage, local oscillator, frequency multiplier, and amplifier. The circuit must be designed for minimal signal loss, noise and intermodulation distortion.
[ Hits: 81 | Votes: 0 | Rating: 0 ]

Repairing HP 8753C VNA - A true detective story about a interesting repair project, putting back to life a malfunctioning HP 8753C VNA that was rebooting after startup with noise and clicking sounds produced by the attenuator and switch relays.
[ Hits: 98 | Votes: 0 | Rating: 0 ]