Friday 9 February 2024

Little Medium Wave radio

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. 


I removed the battery case from the radio to find out what was the engine in this receiver. It turned out to be the IC  KT0936M. After some research I found that the KT0936M is KT Micro's 3rd generation of integrated mono full band FM/MW/SW receiver chip supporting mechanical tuning with embedded MCU. The chip works with a supply voltage of 2.1V till 3.6V, so 2 AAA batteries can do the job. 

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.  . 


Thursday 18 January 2024

Danish eQSL's




Radiofriend Gerard, PA2G, made 2 FT-8 Special Event QSO's with Denmark. The event concerned the inauguration of King Frederik X. I think the eQSL's are quite special.

Thursday 30 November 2023

Solar flare hitting Earth

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.


Monday 30 October 2023

DvdR 2023

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.

NL-Post stand with PA0M and PA2G

Scouting girls making worldwide radio contacts during CQWW SSB contest

Nice antenna designs

My BITX20 caught some attention




Monday 26 June 2023

SDR receiver exploration

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:




Saturday 10 June 2023

Sun

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.

Sunset yesterday from Zuidzijde



Tuesday 6 June 2023

HB9 on 160 m

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.




Note: Description of the balun I use in combination with 25 mtrs of longwire 



Monday 8 May 2023

Start of the Es season

Yesterday I powered up my 4 m equipment. To my surprise I saw EA and 9H stations. No dx  QSO's yet. I did make some local 70 MHz QSO's though. Looks like the Es season is ready to start.



 

70MHz stations that heard my 15 Watt signal 9 July 2023. With some of them I had a FT8 QSO;


First with OK;





Monday 17 April 2023

The Stele of Hatiay

Lately I visited the National Museum of Antiquities (‘Rijksmuseum van Oudheden’) in Leiden. One of the many fascinating objects that amazed me was ‘The Stele of Hatiay’. It shows general Hatiay announcing – in name of his king - that he has established many new sacred memorials (1330-1320 BC). That’s what the text near the stele tells us.



I was intrigued by the triangular shaped device that Hatiay holds in his hand. If you have a close look at the smaller persons, some of them also hold similar devices. In my view the triangular shaped units look like microphones. With a little bit of phantasy we see here something that looks like an early version of an internet teams meeting… Maybe the microphones operate wireless since there is a small piece of (antenna) wire coming from the triangles…



More interesting information on ancient technology:

https://en.wikipedia.org/wiki/Zecharia_Sitchin

https://en.wikipedia.org/wiki/Erich_von_D%C3%A4niken

Friday 7 April 2023

BC860XLT VHF/UHF scanner

Last weekend I re-discovered the Uniden Bearcat BC860XLT VHF/UHF scanner. I did not use it for over 10 years. It is a remarkable receiver covering the frequency range 29 – 956 MHz. It contains 100 channels to store favorite frequencies.




I was glad to find out that the device still works fine. Receiving aircraft AM voice transmissions from Rotterdam Airport and vessel voice communications from the Northsea confirm that the unit is in good shape. Nice toy !

 

Specs:

https://www.rigpix.com/bearcat/ubc860xlt.htm