Topics

1

The RF Workbench / The Perfect Antenna?

« on: October 11, 2020, 0749 UTC »

Does an amateur radio operator need to design a perfect antenna, in order to get on the shortwave (HF, or, High Frequency) spectrum (you know, on the 80/75-, 60-, 40-, 30-, 20-, 17-, 15-, 12-, and 10-Meter Bands)?

Consider: It might not take as much antenna as you may think would be necessary to make two-way contacts on shortwave radio. 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?

Click for the video:



Of course, I want to make a proper dipole out of the example antenna that I show you, in my video.

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 pick up my Morse-code CW signals, especially on 40 meters (the band on which it is tuned physically).

The bottom line for you? Just get something up in the air and start communicating. Improve things over time. You'll have much fun that way.

https://youtu.be/-k5Su--ez2Y

2

General Radio Discussion / Try It, You Might Like It: Software-Defined Radio

« on: August 23, 2020, 1032 UTC »

Software-Defined Radio: Try Before You Buy?

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 Have 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, even while inside 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).

[/QUOTE]

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.

73 de NW7US