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In the classic educational film titled “Electronics at Work,” produced by Westinghouse in 1943, viewers are introduced to the fascinating world of vacuum tubes. This film highlights the crucial role these devices played in both military and commercial sectors, including radio telecommunications, radar, and various industrial applications. The narrative suggests that vacuum tubes provided the United States with a significant advantage during World War II, particularly in enhancing communication and technology.

The Continuing Relevance of Vacuum Tubes

Despite advances in technology, vacuum tubes remain in use today for several applications, including:

– Transmitting radios
– Medical devices
– Audio amplification systems
– High-frequency applications

Understanding Vacuum Tubes

The film outlines the six basic functions of electronic tubes and illustrates how each type is employed in different industrial and military contexts.

Structure of a Vacuum Tube

A vacuum tube typically consists of two or more electrodes housed within a vacuum inside an airtight enclosure. Key features include:

– Electrode Types: Most vacuum tubes have glass envelopes, although some utilize ceramic or metal casings with insulating bases.

– Leads and Sockets: The electrodes connect to leads that pass through the envelope via an airtight seal. These leads often take the form of pins, allowing for easy replacement in a tube socket, as tubes were a common point of failure in electronic devices.

– Capacitive Design: Some tubes feature a top cap on the electrode to minimize interelectrode capacitance, enhancing high-frequency performance and maintaining safety by separating high voltages.

The Evolution of Vacuum Tubes

The earliest vacuum tubes emerged from incandescent light bulbs, which contained a heated filament sealed in an evacuated glass envelope. When heated, the filament releases electrons into the vacuum through a process known as thermionic emission.

– Electrode Functionality: A second electrode, known as the anode or plate, attracts these electrons if it holds a more positive voltage. This mechanism results in a flow of electrons from the filament (cathode) to the plate, creating an electric field due to the potential difference between them.

– Diode Function: A vacuum tube with two electrodes is termed a diode, which functions as a rectifier. Diodes allow current to flow in only one direction, converting alternating current (AC) into pulsating direct current (DC). This technology is widely used in DC power supplies and in demodulating amplitude-modulated (AM) radio signals.

Film Availability and Production Details

This film is available in the public domain under Creative Commons, and it can be accessed through the Library of Congress Prelinger Archives. The film has been edited and converted to HD quality for better viewing. Introductory and closing music is provided by Nero 10, with commercial use rights granted.

This film not only serves as an educational tool but also highlights the enduring legacy of vacuum tube technology in the realm of electronics, illustrating its significant contributions to both past and present technological advancements.

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If you have not yet explored ham radio repeaters, this might be interesting to you.

What is an amateur radio repeater and how do they work?

In this video, with a non-amateur-radio viewer in mind, I chat about the very basic concepts of a repeater.

It is filmed in a relaxed, “ride along with me,” format.

Want to learn more about ham radio (amateur radio)?
Visit: http://nw7us.us/arrl

It might not take as much antenna as you may think would be necessary to make two-way contacts on shortwave radio (as an amateur radio operator putting an HF transceiver on the air). However, often, makeshift antennae are effective enough to be viable–just look at all the contacts many amateur radio operators make with their low-power (QRP) rigs (transceivers) using short, helically-wound, mobile antenna sticks. If they can work magic with such inefficient antenna setups, surely your effort at an antenna would pay off to some degree. Right?

Of course, I want to make a proper dipole out of this example antenna. But, while I wait for the rest of the parts I need to complete this antenna project (pulleys and a ladder, and maybe a potato launcher), I’ve put this makeshift antenna on the air, with it just high enough so that I can enjoy some time on the shortwave bands.

With this antenna, I’ve made successful two-way voice and Morse code contacts (QSOs) with stations in Europe and across North America. I am able to tune it on the 60-, 40-, 30-, 20-, 15-, 17-, 12-, and 10-Meter bands. Reverse beacon detection picks up my Morse-code CW signals, especially on 40 meters (the band on which it is tuned physically).

The bottom line: just get something up in the air and start communicating. Improve things over time. You’ll have much fun that way.

73 de NW7US dit dit

Sure! You don’t need to have a software-defined radio (SDR) before you start learning how to use the technology; there are a few different paths you can take, exploring and learning about SDR.

One way to gain some experience with SDR without spending a dime is to install a free software package for the very popular, non-Linux, operating system (that starts with ‘W’), and give SDR a test drive. If you like it, you might consider getting your own hardware (like the SDRplay RSPdx, for instance), and connecting it up to your computer and running this software, too.

Why I Dived Into SDR

I have always loved radio, ever since the early 1970s, when I discovered shortwave radio. In the last couple of years, I’ve had an increasing interest in the world of SDR. When I am working, but away from home (remember those days, before Covid?), I want to sample news and programming from around the world, but through shortwave. The way to do that, I found, is by using the various SDR options which allow a person to tune a remote receiver, and listen.

I also find working with the waterfall of a typical SDR-software user interface rewarding because, instead of blindly searching for signals in a subband, I can see all of the received signals on the scrolling time representation of a slice of frequency. Simply select that signal on the waterfall, and the radio tunes right to it.

I often connect to different SDR radios around the world, to catch all manner of shortwave signals, from maritime, military air, trans-oceanic air, or coast guard radio traffic, or other interesting HF communications including amateur radio CW and SSB signals. Occasionally, I also check out VHF and UHF signals from around the world. All of that, while instead an office building that is not suited for shortwave radio reception.

I’ve now decided to give back to the community; I’ve added my SDR receiver to the collection of receivers located around the world on the SDRSpace network of SDR radios.

My new SDRplay RSPdx software-defined radio receiver is live, via http://www.sdrspace.com/Version-3, using the SDR Console software (Version 3).

The receivers are online whenever I am not transmitting and when there are no local thunderstorms.

Antenna Port A is connected to a wire antenna (a horizontal 100-foot wire that runs out from my house’s chimney to a tall tree; about 10 feet of that wire is oriented vertically, where the wire passes through a pulley and then is weighted down so it can move with wind-driven tree movement), while Antenna Port B is connected up to a VHF/UHF discone.

Both antenna systems have an AM Broadcast band notch (reject) filter reducing local AM Broadcast-Band radio station signals by about 30 to 40 dB. I need to use these because the very close KLIN transmitting tower is just miles away and those signals overwhelm the receiver. When I use the signal filters, the local AM Broadcasting signals no longer overwhelm the receiver.

In the following video, I first explain my SDR setup, and in the second half of the video, I tune around the radio spectrum, using the software to control my SDR receiver.

A Couple of Questions

After watching this video, WO9B wrote an email to me. Michael asked of me two questions, summed up as:

1. Your SDR window has the IF screen on top. How is that accomplished?

2. Your AM Broadcast filters; more info, please. I live in the area of mucho broadcast stations and that looks like something I could use.

In the following video, I demonstrate how I changed my layout of the SDR Console software. And, I mention the AM Broadcast Filter for SDR Receivers (the hardware filter is found here: https://g.nw7us.us/3kU5SJN).

To Use My Receiver

Download the latest version of SDR-Console from https://www.sdr-radio.com/download – there is a 32-bit and a 64-bit Windows installation package.

The 64-bit installation package may be downloaded from one of these three sources:

1. Google: https://g.nw7us.us/3auBq44
2. DropBox: https://g.nw7us.us/310ooIG
3. Microsoft: https://1drv.ms/u/s!AovWaZDu7Hrd3U-yqK1bs3wuaFw2?e=o4nKeh

The 32-bit installation package can be downloaded from one of these three sources:

1. Google: https://g.nw7us.us/3iLasrZ
2. DropBox: https://g.nw7us.us/3g4VcVc
3. Microsoft: https://1drv.ms/u/s!AovWaZDu7Hrd3U4mJiiRtI9lm70s?e=HDG4ZX

Install the SDR Console package according to the directions given. Once you have the software installed, you will want to add my server. It takes some work to get familiar with the software, but there are online FAQs on how to begin.

One guide on how to add a server to the list from which you can pick may be found, here:

https://www.sdrplay.com/wp-content/uploads/2018/02/SDRConsoleV3-ServerGuide1-1.pdf

I worked on getting all of the bugs worked out of my installation before making the video. It did take some work, and reading up on things. But, the software is solid and a good contender against SDRuno, and HDSDR, and, this way I can share it online with you.

My server is known as, ‘0 NW7US‘ — it will be online when I am not using my antenna systems for transmitting. It will be offline during thunderstorms, or during times when I must use the systems for transmitting.

Software-defined radio is a great way to hear all sorts of communications, from local AM broadcast stations, FM stations, VHF Air Traffic, to shortwave radio stations including amateur radio HF communications.

Thank you for watching, commenting, and most of all, for subscribing; please subscribe to my YouTube Channel: https://YouTube.com/NW7US Also, please click on the bell, to enable alerts so that when I post a new video, you will be notified. By subscribing, you will be kept in the loop for new videos and more.

73 de NW7US

.. (yes, this is an expansion of an earlier post… forgive the redundancy… thank you) ..

My new SDRplay RSPdx software-defined radio receiver is live, via http://www.sdrspace.com/Version-3, using the SDR Console software (Version 3).

The receivers are online whenever I am not transmitting and when there are no local thunderstorms.

Antenna Port A is a wire antenna (100′), while Antenna Port B is a VHF/UHF discone. Both have an AM Broadcast band reject filter, reducing local AM Broadcast signals by about 30 to 40 dB. I need to use these because the very close KLIN transmitting tower is just miles away and those signals overwhelm the receiver. When I use the signal filters, the local AM Broadcasting signals no longer overwhelm the receiver.

Let me know what you think. Enjoy!

To use my receiver:

Install the latest version of SDR-Console which can be downloaded from https://www.sdr-radio.com/download

Install SDR Console according to the directions given. Once you have the software installed, you will want to add my server.

It takes a little to get familiar with the software, but there are online FAQs on how to begin.

My server is known as, ‘0 NW7US‘ — it will be online when I am not using my antenna systems for transmitting. It will be offline during thunderstorms, or during times when I must use the systems for transmitting.

Software-defined radio is a great way to hear all sorts of communications, from local AM broadcast stations, FM stations, VHF Air Traffic, to shortwave radio stations including amateur radio HF communications.

Thank you for watching, commenting, and most of all, for subscribing; please subscribe to my YouTube Channel: https://YouTube.com/NW7US Also, please click on the bell, to enable alerts so that when I post a new video, you will be notified. By subscribing, you will be kept in the loop for new videos and more.

Video:

73!

This is a welfare check on you. Please leave a comment on how you are faring, what is happening in your situation with the lock-down.

Are you quarantined? Working from home? Did you lose your job? How are you doing during this crazy time?

What is going on with you during this challenging situation?

I talk about what I’m doing, too.  I’m quarantined at home.  I can work from home, as I am a senior software engineer.  I can do my job by remote access to a virtual workstation, through a secure VPN connection.  I’m blessed that I still can work during this lock-down.

But, I have a medical emergency – a dental problem – and trying to be seen by a dentist is difficult, because all of the local dentists were told to shut down their daily business and quarantine.  Only emergency appointments are being made!  I was finally, after two days of phone calls, able to schedule an emergency visit to my dentist!

I want to know: How do you use amateur radio, now that we are all stuck at home?  Are you using ham radio more, now?  Less?

Please leave a comment to let me know how you are doing, and answer the other questions, too.  I hope to hear from you.

I hope to meet you on the shortwave amateur radio bands.  I am usually using Olivia, or Morse code CW.  More information about Olivia: http://OliviaDigitalMode.net.

Be healthy, be safe, stay sane!

I got a Skype call a few weeks ago from Eric, 4Z1UG–the creator and host of the QSO Today Podcast–during which he asked me about how and why I got into amateur radio.  Here’s the result.

Eric writes,

We talk a lot about the band conditions due to the Sunspot cycle. Most of it on Facebook and other places is about how “dead” the bands are at this point. We all can’t wait until the cycle starts to rise and we will be making contacts with little effort. I remember in my conversation with Chuck Adams, K7QO in Episode 58, that he really enjoys operating is “Pigrig”, one watt, CW transceiver on 20 meters. When I asked him, (I liberally paraphrase) “but Chuck, the bands are dead. How does that work for you?”. His reply was that while most hams are listening to the bands, he calls CQ until he gets a reply. Works every time.

My QSO this week is with Tomas Hood, NW7US, who has years of expertise in propagation and Solar activity. He is the propagation editor of more than a few radio magazines and websites. In our post-recording conversation we discussed this phenomenon of listening and not calling CQ. I even had this idea that maybe one of the reasons that the digital modes are so successful is because they “beacon”, as part of the whole digital experience, the same as calling CQ. This is why they make contacts. From what I see, looking at PSK Reporter, hams are making lots of contacts worldwide using the digital modes. While SSB may not be working so well, CW and the digital modes seem to work fine.

I like to work on my bench or make the podcast while listening to the bands. Jeff Damm, WA7MLH, in Episode 177, says that he will put his keyer in CQ mode while he is working on a new radio. Invariably, sometimes after many minutes, he gets a reply. Great idea Jeff!

73,

Eric, 4Z1UG

Episode 184 can be found here: https://www.qsotoday.com/podcasts/nw7us

Highlights of Episode 184:

Tomas Hood, NW7US is the propagation editor of a number of shortwave and amateur radio magazines, and has a wide variety of websites, that grew out of his love for all things radio, and for listening on the bands to far off DX and commercial broadcast stations. Tomas shares his understanding of propagation and the lessons we can learn from listening, really listening to the QSOs and exchanges during contest operation.

All of the QSO Today episodes are great.  I enjoy hearing about many different hams.  Do check out all of the episodes that Eric has published.

73 de NW7US dit dit