Some of my projects on this blog are inspired by the radiowork of Roger, G3XBM. I like his transverter designs in particular.
I found that Roger collected a lot of his work in his Project Scrapbook (currently issue 5). It contains a lot of nice experimental data and good projects.
You can find the scrapbook here:
https://sites.google.com/view/g3xbm4/book
Hope you like the scrapbook as much as I do.
During a recent trip to Greece (Attica, Agia Marina) I was able to use one of the radio repeaters near the capital of Athens. The repeater has callsign SV1B and is located on Mt. Pentelikon. RX frequency is 145.775 MHz and shift is -600 kHz. CTCSS is 88.5 Hz.
The Quan Sheng porto worked fine and with callsign SV1/PA2RF I could made some clear qso’s a.o. with SV1IUY.
The little KT0936M receiver IC has surprised me. To find out and explore the possibilties of this chip I made a simple platform.
From a popular supplier of electronic goodies, I purchased a tiny MW/FM radio (not a DIY kit). It does not have a loudspeaker but should be used with headphones. I was interested in the performance of the MW part of the radio.
And that really surprised me. It is a very sensitive receiver for the MW/AM band (530-1600 kHz) using a ferrite rod antenna. I thought nowadays the MW band should be almost 'dead'. But that is not the case. On this small radio I received a lot of broadcast stations past days.
To my surprise the IC covers a wide range from 500 kHz - 110 MHz! The chip has been designed to facilitate following bands:
- Maximum two FM bands with configurable FM frequency range within 32MHz-110MHz
- Maximum two MW bands with configurable frequency range within 500KHz -1750KHz
-Up to 14 SW bands with arbitrary frequency range within 1.75MHz – 32MHz
The KT0936M has a high sensitivity, high signal-to-noise ratio and low distortion.
KT Micro provides following values for sensitivity:
1.6uV EMF for FM
16uV EMF for MW
13uV EMF for SW
IC KT0936M provides direct and simple interface to support mechanical tuning. A pre-programmed low cost EEPROM can also be used to configure the radio band settings. No external MCU is required.
If you search on the internet for KT0936M designs, you can find out how the specific bands can be selected (use of resistor network). The IC should be useable for our radio amateur shortwave bands. At least a BFO has to be added to the design. .
A powerful M9.8-class solar flare erupted from the sun (AR3500) on Wednesday (Nov. 29) at 2:50 p.m. EST (1950 GMT), hurling a super-hot plasma eruption known as a coronal mass ejection (CME) toward Earth. The flare is expected to hit Earth today (Dec. 1, 2023).
Hopefully our internet and radio communication systems can withstand the amount of electromagnetic energy that is brought in by this -almost X-class- solar flare
Note: I have not heard of any damage to communication systems whatsoever.
Last Saturday, Oct. 28, I was part of the ‘NL-post’ team at the DvdR (Day of the Radio Amateur) in Zwolle, IJsselhallen.
I was there with Thieu, NL-199, PA0M and Gerard, PA2G. It was good to speak to fellow radio enthousiastics and see lots of old and new radio stuff. It was remarkable that my homebrewed BITX20 from 10 years ago - built in ‘Manhattan style’ - draw a lot of attention.
Great fun with SDR Receiver MSI2500 in combination with SDRuno software. I am exploring the possibilities of this nice toy.
The SDR receiver (frequency range 30 - 1000 MHz) has 5 antenna inputs each with its own bandfilter
SDRuno software in action ( Repeater PI2NOS, 430.125 MHz selected)
Experiment with E-field antenna for low frequency signals (< 10 MHz ).
I wrote an article for the Dutch radiomagazine Electron, NL-Post, Nov. 2023, about this SDR receiver:
Yesterday evening I witnessed the sunset from my backyard garden.
I realized that it is amazing that a star at a distance of 150 million kilometers from us affects the propagation of radio signals on earth. During daytime the solar wind presses the Kennelly-Heaviside layer closer to the earth, thereby limiting how far it can reflect radio waves. The effect is also influenced by the amount of sunspot activity.
For a change, last week I was active on 160 m. With my end-fed longwire antenna - in the evening hours - I managed to work a couple of stations. One of them was HB9EFK. This was my first with Switzerland on 160 m.
