Firstly Radio VNG was Australia's official time and signal service. It provided highly accurate and stable reference signals on 2.5, 5, 8.638, 12.984 and 16Mhz. This particular radio receiver was fixed tuned to 5 Mhz to pick up the always accurate time-of-day encoded information which was part of the 1 Khz modulation tone. This had been used for an always accurate digital clock display. This topic of a Radio VNG 5 Mhz Receiver will demonstrate many of the principles in the tutorials presented on this site including active antennas, impedance, resonance, toroids, impedance matching, band pass filters, low pass filters, oscillators, receivers and digital basics. Links to the appropriate electronic tutorial will be provided.

WWW.ELECTRONICS-TUTORIALS.COM

LAST MODIFIED:

RADIO VNG 5 MHZ RECEIVER


Why a Radio VNG 5 Mhz Receiver?

Firstly Radio VNG was Australia's official time and signal service. Sadly, it no longer exists having been overtaken by GPS time technology. It was maintained by Australia's National Standards Commission and provided highly accurate and stable reference signals on 2.5, 5, 8.638, 12.984 and 16 Mhz.

The rest of this article [sniff!] has been retained solely for historical purposes

This topic of a Radio VNG 5 Mhz Receiver will demonstrate many of the principles in the tutorials presented on this site including active antennas, impedance, resonance, toroids, impedance matching, band pass filters, low pass filters, oscillators, receivers and digital basics. Links to the appropriate electronic tutorial will be provided.

If you have access to a quality short wave receiver check out those stable reference signals on 2.5, 5, 8.638, 12.984 and 16 Mhz and PLEASE do send me a signal report from your area. BTW do not confuse the 5 Mhz with the strong WWV signal in the USA. This project can be modified for the reception of the other VNG frequencies.

I was an old time financial contributor to the VNG Users Consortium back in the days when it looked like the service would be abandoned in the name of the "holy grail" of economic rationalism. Thankfully, solely due to the co-operative efforts of so many great and wonderful people, it was able to be retained and then ultimately taken over by Australia's National Standards Commission.

This particular radio receiver will be fixed tuned to 5 Mhz to pick up the always accurate time-of-day (within one milli-second) encoded information which is part of the VNG 1 Khz modulation tone. This will then be used to build an always accurate digital clock display.

VNG time-of-day encoded information for a digital clock display

Radio VNG transmits time-of-day and day-of-year information as a modulated tone in the form of BCD (binary coded decimal) format throughout the 21st to 35th second inclusive after the synchronizing 200 mS pulse at the beginning of the 20th second past the minute. A 200 mS (milli-second) burst of 1 Khz (1,000 Hz) equals a binary one while a 100 mS burst of 1 Khz equals a binary zero. The full VNG time code format can be viewed here in figure 1 below.

This image is copyright © by Ian C. Purdie VK2TIP - VNG time code format

Figure 1. - VNG time code format

If you don't understand the in's and out's of the BCD format and the concept of binary one's and zero's then go to digital basics for a better grasp of that topic.

Building a Radio VNG 5 Mhz Receiver for a digital clock display

In figure 2 below is a block diagram of our Radio VNG 5 Mhz Receiver. We will then discuss each section individually. Incidentally I will actually be constructing this project in the real world but, I'm electing to build the Radio VNG 5 Mhz Receiver "UGLY" style. That means "point-to-point" wiring on a piece of printed circuit board (PCB) rather than a dedicated PCB. WHY?, cost! I no longer have neither the facilities nor the inclination to etch a one off PCB myself. I can put one through a drawing program and have it made. The cost of that alone would exceed the cost of everything else in the project put together.

This image is copyright © by Ian C. Purdie VK2TIP - radio vng 5 mhz receiver block diagram

Figure 2. - Radio VNG 5 Mhz Receiver block diagram

Active antenna stage

I thought I rather elegantly covered the topic of active antennas on my old site some time ago. Naturally that is an incredibly biased opinion. On the same site I provided a suggested a somewhat near example for the radio telescope project. We will be duplicating that one here, heh!, heh!. I'm a big believer in re-cycling anything from rubbish to projects to gif files. Some modifications will be needed of course.

This image is copyright © by Ian C. Purdie VK2TIP - original amplifier to be used as an active antenna for radio vng 5 mhz receiver

Figure 3. - Original amplifier to be used as an active antenna for Radio VNG 5 Mhz Receiver

Because I'm going to connect to a short telescoping antenna I need to amend the input circuit. The output circuit just needs to be modified for connection to the Radio VNG 5 Mhz Receiver which in actual fact is a 16 pin Philips TDA1072A AM receiver integrated circuit or AM radio on a "chip". I suggest you review some of my comments about this amplifier and associated filters in the radio telescope project page.

This image is copyright © by Ian C. Purdie VK2TIP - revised active antenna for radio vng 5 mhz receiver

Figure 4. - Revised active antenna for Radio VNG 5 Mhz Receiver

More next week or whenever.......

RELATED TOPICS on VNG radio receiver

resonant frequency

am radio receivers

radio receiver basics

tuned radio frequency TRF receivers

regenerative radio receivers

fm radio receivers

Link to this page

NEW! - How to link directly to this page

Want to create a page link to me from your site? It couldn't be easier. No HTML knowledge required; even the technophobes can do it. All you need to do is copy and paste, the following code. All links are greatly appreciated; I sincerely thank you for your support.

Copy and paste the following code for a text link:

<a href="https://www.electronics-tutorials.com/receivers/vng-receiver.htm" target="_top">visit VK2TIP's VNG Receiver Page</a>

and it should appear like this:
visit VK2TIP's VNG Receiver Page

the author Ian C. Purdie, VK2TIP of www.electronics-tutorials.com asserts the moral right to be identified as the author of this web site and all contents herein. Copyright © 2000, all rights reserved. See copying and links. These electronic tutorials are provided for individual private use and the author assumes no liability whatsoever for the application, use, misuse, of any of these projects or electronics tutorials that may result in the direct or indirect damage or loss that comes from these projects or tutorials. All materials are provided for free private and public use.

Commercial use prohibited without prior written permission from www.electronics-tutorials.com.


Copyright © 2000 - 2001, all rights reserved. URL - https://www.electronics-tutorials.com/receivers/vng-receiver.htm

Updated 16th March, 2001