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Today — 25 July 2024Main stream

Radio Waves: Who Will Pay, Ham Radio Culture, OTH Support, CarnationFM, Night of Nights, and 100 Years of Radio

By: Thomas
25 July 2024 at 10:09
Radio Waves:  Stories Making Waves in the World of Radio Welcome to the SWLing Post’s Radio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy! Many thanks to SWLing Post contributors Richard Cuff, Dennis Dura, David Korchin, Roger Fitzharris, David Iurescia, and NT for the following tips: In 1924, a […]

WIA News Netcast for Sun, 28 Jul 2024

WIA President Scott Williams VK3KJ bringing to the attention of Affiliated Clubs, some VERY important reminders. - Alan, VK4SN, the WIA's Trans Tasman and RD contest manager. - Shane VK4KHZ with an update of upcoming ARISS events in our region. - Editor-in-Chief of Amateur Radio magazine, Roger Harrison VK2ZRH.

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AMSAT-UK Space Colloquium 2024

By: Editor
25 July 2024 at 06:50

Kents Hill Park Conference Centre Milton Keynes MK7 6BZAMSAT-UK is pleased to announce that the 2024 Colloquium will take place alongside the RSGB Convention at Kents Hill Park Conference Centre, Milton Keynes, MK7 6BZ on the weekend of 12/13th October 2024.

As in previous years, the AMSAT-UK Colloquium will run as a separate stream within the RSGB Convention and will include presentations on a variety of satellite and space related topics.

The Annual General Meeting of AMSAT-UK will take place during the colloquium.

An AMSAT Gala Dinner will be held on the evening of Saturday 12th October at the Marriott Delta Hotel on Trimbold Drive, Kents Hill, Milton Keynes MK7 6HL. Attendance is restricted this year at the hotel and a limited number of tickets are on sale via the AMSAT-UK Online Shop https://shop.amsat-uk.org/

The cost of the Gala Dinner is £39 per person and includes a three course meal with tea / coffee at its conclusion.

Alongside the Gala Dinner, AMSAT-UK has negotiated a deal at the Marriott Delta for the evening of Saturday 12th October 2024. These rooms include breakfast on Sunday 13th and are priced at £89 per room for single occupancy. Tickets for the Gala Dinner can be purchased on the AMSAT-UK Online Shop.

Bookings for the Gala Dinner are now available on the AMSAT-UK Shop, but must close on 1st October 2024 unless sold out sooner, so please book early to avoid disappointment.

Entrance to the RSGB Convention is managed by the RSGB and you will be required to purchase Day Tickets for the Saturday and/or Sunday to attend the AMSAT-UK Colloquium.

RSGB Convention booking is at https://rsgb.org/main/rsgb-2024-convention/

The schedule of Colloquium talks will be released closer to the date.

DIY RF Field Strength Meter / Detector With Audible, Visual, And Digital Indicators (Based on 555 Timer And Simple Parts)

By: KM1NDY
25 July 2024 at 06:01

This was a little rabbit hole. On some amateur radio forum somewhere someone mentioned the MFJ-802B RF Field Strength Meter. This piqued my interest because I had not realized that a field strength meter was a consumer accessible device. Turns out there are all sorts of RF meters and detectors available to purchase. Who knew?

This collided me into the homebrew versions of RF detectors. One that caught my eye, and inspired this project was “The Squeakie” by VK3YE. It requires a handful of components, all of which I had. I built it mostly to spec on a breadboard, adding only an extra trimpot to control the volume. Then I soldered it onto perfboard and it, after a bit of troubleshooting, worked exactly as advertised. In short, it squeaks at a proportionally higher pitch when it encounters radio waves. This means it is useful as an audible RF field strength meter. You could use it to detect RF while fox-hunting, or to test the radiation pattern of an antenna, or to annoy your significant others… In short, it is a voltage-controlled oscillator that increases in frequency in the presence of an RF signal.

So I built The Squeakie, and sure enough one tap on my HT, and the little guy was shrieking. Below gives you a rough sketch of how I positioned and connected everything. This perfboard is of the type that all of the holes in each individual row are interconnected (and represented by the printed lines on the page).

So how exactly does The Squeakie work? My modification of VK3YE’s Field Strength meter is shown in part below (circuit constructed with Multisim).

Let’s start with D1, which is the switching diode 1N4148. In this application, the diode is acting as a rectifier, transforming an RF signal coming from the antenna into direct current.

Next let’s discuss the 555 Timer IC. This circuit is set up in “astable” mode, which means that the 555 timer is going to oscillate between an output of VCC and zero volts indefinitely with a regular and predictable voltage-dependent frequency. The tying of the threshold (pin 6) and trigger (pin 2) together puts the 555 in a permanently unstable state flipping between “on” (with a voltage equivalent to that seen on pin 8, i.e. VCC) and “off” (zero voltage) producing an endless square wave.

Resistors R1 and R2, along with capacitor C3 work together to produce the frequency of the 555 Timer output. In the situation where VCC is the only voltage source, the threshold/trigger flip-flop produces a stable oscillation. But in our circuit, the antenna acts as an additional voltage source in the presence of RF, adding to the VCC, and resulting in more swift oscillations (i.e., an increase in frequency of the output square wave signal).

The VCC crosses the R5 resistor, 20kΩ potentiometer, and the R4 resistor , which act as an adjustable voltage divider, creating a forward bias on the 1N4148 diode. The 20k POT can be adjusted to increase or decrease the voltage either toward the diode or toward ground, and in turn, change the frequency of the timer output. An additional voltage supplied by the antenna and rectified by the diode will increase that frequency.

The output voltage, rhythmically oscillating between VCC and zero volts, will cross through an electrolytic capacitor and to an 8Ω 0.5W loudspeaker whose volume is controlled by a 200Ω potentiometer. Running in parallel to the loudspeaker is also an LED that’s brightness will be increased or decreased with the frequency (and duty cycle) of the timer. And also an output lead to provide a readable input to a microcontroller is also available. In this case I used an Arduino Nano as well as a 1602 LCD screen.

The above EasyEDA schematic shows my entire finalized project. Or I supposed at least version 1.0. This includes placement of a DPDT switch (SW1) to switch from the Nano to the loudspeaker. A second switch (SW2) to switch the output to the Nano on or off. Three 2-port terminal blocks for the voltage source, antenna, and loudspeaker. The Arduino Nano and it’s connections to the 1602 LCD screen. And finally, the code I programmed for the Nano that would convert the output reading of the RF meter into a corresponding number. I’ll talk more about the code later on.

Below shows the entire breadboarded project, fully operational. In my version, not only does it squeak in higher frequencies (and have an adjustable volume) in the presence of RF above ambient background noise, it also brightens an LED proportional to RF signal strength, and displays a relative numerical meter reading. The antenna is just a length of wire tied into the positive port of the terminal block.

And just a close-up of the placement of the components. You will notice that the readout number is much less bright than the words “RF Strength”. I think this is due to the very quick oscillations of the device, of which I tried to account for somewhat in my rudimentary code. Hey, what can I say? It needs work.

I did go ahead and convert my EasyEDA schematic into a PCB through JLCPCB. Remember, I do not accept sponsorship from anyone. I actually cannot believe how easy it is to acquire a circuit board from this company.

The unpopulated rendering of the PCB is shown below. And the partially populated board is above.

And an exact Bill of Materials below.

And finally the code!

#include <LiquidCrystal.h>

int rs=7;
int en=8;
int d4=9;
int d5=10;
int d6=11;
int d7=12;
LiquidCrystal lcd(rs,en,d4,d5,d6,d7);

int maxVal = 0;
uint32_t lastSample = 0;

void setup() {
Serial.begin(9600);
lcd.begin(16,2);

}

void loop() {

if (millis() - lastSample > 1000) {
lastSample = millis();
Serial.println(maxVal);
maxVal = 0;

}
int reading = analogRead(1);
if (reading > maxVal) {
maxVal = reading;
}
lcd.setCursor(0,0);
lcd.print("RF Strength: ");
lcd.print(maxVal);
lcd.clear();


}


What can I say? The firmware sure isn't pretty, and it doesn't even give you great results. But it does kinda work. I will probably spend some time working out different ways to produce more meaningful results from the readable Nano lead of this device.

This was a great and instructive project to work through for me. It also lends itself to a really easy soldering project for hams, or students, or individuals, particularly if you only build the part with the loudspeaker, or even the original “The Squeakie”. I think it is putting me one step closer to building my own receiver, which is something I have made a few attempts at so far.

May we meet again!
KM1NDY

NanoVNA-H4 radio remote trial #5 – NanoVNA enhancement

By: Owen
25 July 2024 at 05:29

A series of four articles explored different wireless solutions for remote operation of a NanoVNA-H4.

The NanoVNA-H4 can use a USB connection, or a serial connection, the UART, selected from the configuration menu. The UART ‘channel’ is a conventional unprotected asynchronous protocol, 8N1, and supports a range of DTE speeds.

Three different wireless remote solutions were trialed, and an inexpensive Bluetooth adapter showed the most promise. The air-link is a ‘reliable’ link in terms of error free transmission, though of course it depends on adequate signal strength. Importantly, even at 115200bps DTE speed, it did not seem to suffer buffer overruns, an important detail given the lack of effective flow control in the NanoVNA-H4 UART interface (as brought to the edge pads).

In response to the need for a more efficient data transfer for screenshots (~399kB), Dislord has released a version of NanoVNA-D that supports a RLE compressed screenshot download.

The Python script published at https://github.com/owenduffy/tinydevicecapture allows standalone screenshot capture using the new “capture rle” command which permits screenshot download in 2-5s at DTE speed 115200, less than a quarter the uncompressed image.

Last update: 25th July, 2024, 4:54 PM

Radio Rocket Version 4

24 July 2024 at 08:00

What’s in a name?

Quite a lot if it’s long enough!

I figured there would eventually be a Radio Rocket Version 4, once we we learned something interesting enough, or had an idea for a new design for the electronics or the rocket that warranted building the next version. As it turns out, a number of those things came together at once:

  • I stumbled across a product that gave me an idea for a redesign on the main CPU board
  • The redesign above would warrant redesign of the various modules
  • I wanted to try to design some of my own modules, instead of relying on breakout boards
  • The 12 year old had an idea for a new design for the actual rocket

So while we are going to continue doing stuff with version 3 and plan to do more launches to test out more ideas with the current hardware, and will keep version 3 in our flight rotation for the forseeable future, we decided it was time to start planning and building version 4!

but as always, before I get into the details, Let’s get the plugs out of the way!
support some repeaters financially, or with donations of equipment, or by connecting an existing repeater to the Pride Network. Donations of cash, or commitments to connect existing repeaters to the Pride Network have the biggest and fastest impact!

if donations aren’t your bag, Buy some cool stuff to support the projects - the margins are smaller, but walking around town, going to club meetings, or heading out to a hamfest, while wearing the swag helps bring more attention to the effort, so can be very impactful in the long run!

Getting to the Name

Those who have been following along are likely aware, but we have been using Sushi and Fish related terms for the various versions of our rockets, and we’ve been going in alphabetical order, to try and keep it clear which one comes after which. That means that for version 4, we needed a Sushi/Fish related word that starts with a Q.

We struggled for a while coming up with something, until we stumbled across a species of Hagfish called “Quadratus.” I liked the ring of it, and the 12yo pointed out that the “Quad” prefix was also a perfect match for our fourth rocket.

While siting with that idea, we were chatting about rockets in general, and I mentioned that I thought it would be fun to do a rocket that had side pods. Again, the 12 year old was quick to point out that it should probably have 4 pods, in keeping with the “Quad” theme. I was down with that, so we moved on to talking about what the main part of the rocket should be like. Being a fan of the Big Bertha series of rockets, 12 said “Bertha of course!” to which my spouse chuckled and said, “Bertha the Hagfish.” which honestly felt like just as good of a name as Quadratus.

Being fans of unnecessarily long names, we kicked some additional ideas around, the 12 year old drew up a logo, and we landed on a final name for our rocket, so without further ado..

Introducing…

The words "Radio Rocket Version 4, Quadratus, aka Berth, Queen of the Hagfish, and a pencil drawing of a Hagfish wearing a crown and holding a scepter

3D rendering of a rocket with 3 side pods

3D rendering of a PCB board wtih a hagfish logo on it

Whats next?

There will be lots of information coming and getting shared as we build version 4. We’re still pretty early in the process, but we already have a pile of rocket parts to start assembling the body, and the first boards for the new electronics package are making their way from the fab house to us, so things should move along very nicely. Redesigning and fabbing the new modules will take some time, but I’m hoping that throughout the rest of the summer we’ll do a couple more launches version 3, and with a bit of luck we may be able to start making launch plans for version 4 sometime this fall or winter.

Till then!

Churches and Chapels on the Air 2024

Churches and Chapels on the Air (CHOTA) 2024 will take place on September 14th. CHOTA was first established in 2013 and encourages fellowship among both activators and chasers.

A list of participating stations is available on the CHOTA 2024 website. CHOTA is managed by The World Association of Christian Amateurs and Listeners (WACRAL).

Source: K4FMH

Yesterday — 24 July 2024Main stream

A bit of catching up…

By: VA3QV
24 July 2024 at 22:42

There has been lots happening and no time to keep you in the loop and so here (once again) is the “Coles Notes” version.

The POTA Support your Parks event went better than I expected.

There were some family issues that kept me from taking my FT891 out into the local parks for activation.

However I did manage (as a hunter) to get 35 activators in my log with resulted in 6 new parks in my log as I slowly (very slowly) get towards the 3000 unique Parks in my log.

A bit of a “shucks” happened when a deal I had made for some new equipment for the shack fell through.

The other party (to his credit) cancelled the deal when he found out there was problem with the radio I was about to acquire from him.

It will need major repairs and most likely will not be finding its way into my shack.

And the final “downer” for the week happened yesterday. I entered a contest at our local FM broadcast radio station with the prize being a trip for 2 on a River Cruise along the St Lawrence River and last week they informed me that I won the trip for 2. Liz and I started to make plans

Yesterday I got given notice that the cruise had been cancelled and on the Radio Stations website I found this:

The radio stations, and its TV affiliate has laid off most/all of their on air staff as their Parent Company Corus Entertainment tries to restructure so they can stay afloat (no pun intended).

This is part an an email sent to me (the day after I got notified by the ticket agent that they had cancelled) by Corus which reads as follows”

“I want to thank you for supporting 96.3 BIG FM, and for purchasing tickets to the boat cruise.  Due to recent staff changes, we don’t think it’s the appropriate time to be holding a party boat cruise and have decided to cancel the event.“

Liz was looking forward to the evening out and we will still go somewhere but our feet will stay dry. (a small pun intended here)

Thinking about an earlier “3 Hour Cruise” from the past…has me thinking that keeping dry might be a good thing .

This would be the Punny side of life I guess…

73bob

Logs 24 Jul 2024

By: uk dxer
24 July 2024 at 20:33

1233 2011 Radio Rock Revolution. SINPO 24432. Not on 5880
1611 2005 Radio Luka. SINPO 33433.
1620 2027 Radio Delfzijl. SINPO 34433.
1648 2042 Radio Perenboom. SINPO 44433.
1654 2020 Radio Romax. SINPO 33433.
5030 1809 Deltracks. SINPO 34433.
6272 1800 FRS Holland (via unid). SINPO 55444. 

Quietly Logging QSOs – Discarded Drafts and Lots going on

As mentioned a number of drafts didn’t make it past my efforts to finalize. Instead I dumped them. Hence the rather sudden breakdown in what had been a steady flow of posts. Will recreate some of the ideas in fresh writings, but it takes time. Have a lot going on at the moment, which makes […]

Giving a helping hand to Island Radio

  Washington Island has a new internet based “radio” stream that is doing the community based FM project thing coming up. https://www.washingtonislandradio.com/ I’ve been too busy to follow the rule changes that have allowed this to happen or the actual Island project, but when they put out a call for some help I decided to […]

Counterpoises for Radio Engineers

By: ve3ips
24 July 2024 at 14:59

A counterpoise is an essential component in vertical antenna systems, especially when the antenna lacks a natural ground connection. Its purpose is to provide a stable, low-resistance ground plane that helps balance the antenna’s impedance and optimize its radiation pattern.

Purpose of Counterpoises

  1. Completing the Circuit: In a vertical antenna system, the ground or counterpoise acts as the return path for the radio frequency (RF) currents. The antenna itself is one half of a dipole, radiating the signal, while the counterpoise serves as the other half, completing the electrical circuit. Without an adequate counterpoise, the antenna system can experience poor performance due to unbalanced currents and increased impedance.
  2. Impedance Matching: A well-designed counterpoise helps achieve impedance matching between the antenna and the transmission line. Proper impedance matching is crucial for efficient power transfer from the transmitter to the antenna, minimizing power loss and reflections that can cause signal degradation.
  3. Improving Radiation Efficiency: The counterpoise provides a conductive surface that helps control the flow of RF currents near the antenna’s feed point. This helps prevent energy from being absorbed by the ground, which can be lossy, especially in poor soil conditions. By providing an artificial ground plane, the counterpoise increases the antenna’s efficiency, allowing more of the transmitted power to be radiated into the air.
  4. Controlling Radiation Pattern: The counterpoise influences the antenna’s radiation pattern, particularly the take-off angle of the radiated signal. The arrangement and length of the counterpoise elements can be adjusted to optimize the antenna’s radiation pattern for specific communication needs, such as long-distance (DX) contacts or local (NVIS) communications.

Why Counterpoises are Needed

  • Poor Natural Ground Conditions: In many locations, the natural ground may not be conductive enough to serve as an effective return path for RF currents. This can be due to poor soil conductivity, such as sandy or rocky terrain. A counterpoise provides a controlled and predictable ground plane that compensates for these deficiencies.
  • Elevated Antenna Installations: When vertical antennas are installed above ground level, such as on rooftops or towers, they may be isolated from the earth ground. In these cases, a counterpoise is essential to create a virtual ground plane, ensuring the antenna system functions correctly.
  • Minimizing Ground Losses: In systems where the antenna is close to the ground, RF currents can induce losses in the earth, reducing the system’s overall efficiency. A counterpoise reduces these losses by providing a low-resistance path for the return currents, keeping more energy in the radiated signal.
  • Flexibility in Design and Deployment: Counterpoises offer flexibility in antenna design and deployment. By adjusting the length, number, and placement of the counterpoise wires, engineers can fine-tune the antenna system’s impedance, resonance, and radiation pattern.

In summary, counterpoises are a crucial component in vertical antenna systems, ensuring efficient operation by providing a stable ground plane, improving impedance matching, enhancing radiation efficiency, and optimizing the radiation pattern. They are especially important in situations where natural ground conditions are poor or when the antenna is elevated above the ground.

John IPS

time for a nap

laugh, cough, sneeze Poise has you covered

Counterpoise explained to a Child

By: ve3ips
24 July 2024 at 14:58

A counterpoise is like a special set of wires that help a vertical antenna work better. Imagine an antenna as a talking stick that sends and receives radio signals. But just like when you’re talking, you need a good place to stand to be heard clearly, an antenna needs a good “ground” to send and receive signals well.

In the case of a vertical antenna, the counterpoise acts like a stage for the antenna to stand on. It helps the antenna send out strong signals and hear signals from far away. Without a counterpoise, the signals might be weak or not go very far. It’s a bit like if you were trying to shout from the middle of a thick forest; the trees would muffle your voice. A counterpoise helps clear away those obstacles, making the antenna’s voice louder and clearer.

So, just as you need a good place to stand to speak clearly, a vertical antenna needs a counterpoise to work its best!

Ve3IpS

As a nerd it makes no sense to me

Is it Radials or Counterpoise or Ground wires – Its all the same wire

By: ve3ips
24 July 2024 at 14:39

Read “A Study of Elevated Radial Ground Systems” by K3LC

Al Christman, K3LC, conducted a study on elevated radials, which he published in the January/February 2005 issue of the National Contest Journal. His article, “A Study of Elevated Radial Ground Systems for Vertical Antennas — Part 1,” was also included in the book More Vertical Antenna Classics (2006) by the American Radio Relay League.

BUY the latest ARRL Handbook for a ton of info on antennas

Christman investigated the performance of vertical antennas to determine the optimal number of radials needed for efficient low-band operation at various heights above different soil types.

In his study, Christman used configurations with three to six uniformly spaced #12 AWG copper wire radials, each cut to a quarter wavelength, including the vertical element. He also emphasized the importance of soil permittivity, measuring system characteristics over poor, average, and good soil.

The study features nine tables detailing his findings. For example, at a frequency of 7.15 MHz over poor soil, Christman found that three evenly spaced radials at a height of five feet resulted in -0.98 dBi of gain with a take-off angle of 27 degrees. In contrast, six evenly spaced radials at 15 feet yielded -0.29 dBi of gain and a take-off angle of 23.5 degrees.

Christman recommended installing at least four radials evenly spaced around the vertical antenna. He noted that efficiency improves with increased height, providing slight additional gain and lowering the take-off angles.

So some proof about radilas and ground vs elevated and at the end of the day dont sweat it just pick one method and enjoy operating from a local park.

John VE3IPS

K3LC has many many articles on these concepts

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