Archive for the ‘ham radio’ Category
Just Get On The Air! (A Makeshift Temporary Dipole Shortwave Antenna)
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?
[embedyt] https://www.youtube.com/watch?v=-k5Su–ez2Y[/embedyt]
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
Which HT For High RF SOTA?
On some SOTA summits that are established radio sites, there can be significant RFI on 2 meters. I recently wrote about that here: RFI on SOTA Summits. There have also been discussions from time to time among VHF SOTA activators on which handheld transceiver (HT) has the most robust receiver for use in high RF environments. (Hint: a Baofeng is not going to be your best choice.)
This led me to an excellent web page by Razvan/YO9IRF that tabulates the receiver performance of HTs as measured in the ARRL lab. This is arguably the most objective look at HT performance out there. You can do a sort on a particular parameter and see which models are best.
Probably the parameter to start with is wide 3rd-order intermodulation on the 2-meter band. (I am going to ignore the 70 cm performance because most VHF SOTA contacts are on 2 meters.) The wide 3rd-order intermod performance relates to interference rejection from outside the amateur band.
Here are the best performing HTs for this parameter. (Go to the website directly to see other models listed.)
Interestingly, the Icom IC-V8 jumps to the top of the list. This is an older single-band 2m radio…and I happen to have one hiding somewhere in the basement. I am a bit surprised there are two Wouxun radios near the top of the list but they performed well. No surprise that the Yaesu FT-60 shows up…it seems to be well-regarded by SOTA activators.
The narrow 3rd-order intermod performance relates to the receiver performance inside the amateur band. Sorting based on that parameter shows these radios at the top:
The Kenwood TH-22AT takes the top position, followed by the Yaesu FT-10R, both older single-band radios. The general trend here is that some of the older radios, especially single-band rigs, have better front end filtering. Newer radios tend to include reception of a wider range of frequencies outside the ham band and have receiver front ends that are correspondingly more open. The Radio Shack HTX-202 gets a lot of positive comments from the SOTA crowd and is on the shortlist. Again, the well-regarded FT-60 makes the list.
Let’s check a few of my favorite HTs to see how they rate.
My usual SOTA handheld is the Yaesu FT-1DR. The wide 3rd-order intermod is 73 dB, or 12 dB worse than the FT-60 (85 dB). For narrow 3rd-order intermod, the FT-1DR is 58 dB vs 67 dB for the FT-60. This matches my impression that the FT-1DR does OK for most summits but is not the best radio for high RF environments.
Another radio to consider is the Yaesu FT-4XR. I often have this radio on at the house but I don’t use it for SOTA. This radio uses the same receiver IC as the Baofeng UV-5R but has better input filtering. The wide 3rd-order intermod is only 63 dB and the narrow 3rd-order is 61 dB (about the same as the FT-1DR). The table does not list any Baofeng radios but I would expect them to perform worse than the FT-4XR.
Regular readers of this blog know that I use a Yaesu FT-90 mini-mobile transceiver for most SOTA activations. I looked up the ARRL tests on it. The wide and narrow 3rd-order intermod are 85 dB and 65 dB respectively, not better than the best handhelds but near the top. My experience is that the FT-90 receiver is better than my FT-60 and FT-1DR, consistent with the ARRL lab measurements.
Another radio of interest is the Yaesu FT-818, which the ARRL measured as 96 dB (wide 3rd-order intermod) and 72 dB (narrow 3rd-order intermod) on the 2m band. This puts the FT-818 at the top of the list with the best handhelds. Actually, I would have expected it to be even better, far superior to an HT, but apparently not.
So I need to dig out that old Icom IC-V8 that is hiding in the basement. It may be a good piece of equipment to have along on SOTA activations.
73 Bob K0NR
The post Which HT For High RF SOTA? appeared first on The KØNR Radio Site.
My Comments On The Proposed FCC License Fees
You have probably heard about the FCC proposal to establish a $50 application fee for Amateur Radio licenses. This is part of an overall redesign of the FCC’s fee structure, affecting many radio services, not just amateur radio.
The Notice of Proposed Rule Making (NPRM) is found in Docket 20-270. The public is invited to submit comments on the proposal via the Electronic Comment Filing System (ECFS). It is relatively easy to do. You can upload a document with your comments or use “express comment” to just type in your comments. If you are short on time, you could simply submit a few sentences supporting or opposing the licensing fee along with your reasoning. The only tricky thing you need to know is the proceeding number: 20-270.
I thought this was important enough that I put together my thoughts and submitted them. The short version of my comments are:
- The $50 fee seems excessive, compared to the cost of relatively simple amateur radio license transactions. (If it really costs the FCC $50 to do this, they need to redesign their system.)
- The $50 fee will be a barrier to getting an amateur radio license for many potential licensees. That’s my opinion based on interacting with a large number of new licensees coming through our club’s Technician license class.
- I support charging a smaller fee, in the range of $15 to $25.
You can read my complete comments here:
Robert Witte K0NR Comments MD Docket No. 20-270
73 Bob K0NR
The post My Comments On The Proposed FCC License Fees appeared first on The KØNR Radio Site.
Perfect Straight-Key Morse Code? Can It Be Made Without Machines?
RFI on SOTA Summits
One thing to watch out for when doing SOTA activations is the presence of strong Radio Frequency Interference (RFI) on some peaks. The typical scenario is that the summit is also an established radio site with transmitters that interfere with your ham radio operations.

I use the VHF/UHF bands for SOTA, so I am writing from that perspective. My impression is that HF interference is much less likely because these radio sites don’t usually have any HF transmitters. However, they may have broadband noise sources such as networking equipment, power line arcing or switching power supplies that can create problems on HF. Anyway, this post is focused on 2 meters and higher bands.
In my experience, the transmitters at radio sites may include land mobile repeaters (VHF or UHF), NOAA Weather (162.xx MHz), TV/FM broadcast stations and mobile wireless (cellular) systems. The TV/FM broad stations are really bad news because they run a crapton of RF power.
The worst summit I have encountered is Sandia Crest (W5N/SI-001) near Albuquerque, NM. See trip report here. They even have a sign in the parking lot to warn you that the RFI may wipe out your car’s keyless remote.

Some other notable RFI-heavy SOTA summits are Monarch Ridge South (W0C/SP-058), Squaw Mountain (W0C/PR-082), Terry Peak (W0D/NW-002), and Greentop (W4T/SU-076).
In a high RFI environment, your radio receiver gets overloaded such that you can’t hear stations calling you but they can hear you just fine. This results in the SOTA activator calling and calling while the chasers get frustrated that the activator never hears their call. Not good. It may not be obvious that this is happening. This blocking of the receiver may come and go, depending on which transmitters happen to be active.
Mitigation Strategies
There are a few things that you can do to deal with the RFI:
Move Away From The Source
Probably the first thing to try is just moving away from the source of interference. This may mean moving away from the highest point on the summit but it may be better overall to give up a few feet of elevation to not have the interference. You’ll need to stay in the activation zone to be a legitimate SOTA activation.
Use A Better Radio
Some radios are better than others when it comes to receiver performance including the ability to reject unwanted signals. The low cost radios from China (Baofeng or similar) generally have lousy receivers so they are a poor choice for operating from an RFI-intense summit. Many people report better results with the Yaesu FT-60, a solid performer. Commerical radios from Motorola are even more robust. I’ve been using a small mobile radio for SOTA (Yaesu FT-90) which outperforms most handheld radios.
Change Your Antenna
Using a directional antenna can help…just point it away from the source of the interference. Oddly enough, using a worse performing antenna can help improve your ability to communicate. For example, a rubber duck antenna on a handheld radio will allow less of the interfering signal to get into your receiver which may improve your ability to receive. As long as the antenna is “good enough” to complete the radio contact, it may be the way to go. One trick I’ve used is to deploy two radios, one for receive with a crummy antenna and the other for transmit with a better antenna. That way, you still radiate a stronger signal while reducing the interference into the receiver.
Use A Bandpass Filter
You can insert a filter into your antenna feedline to reduce the interfering signal. The best approach is to use a bandpass filter that passes the frequency you are operating on but attenuates other signals. SOTABeams offers a compact bandpass filter for the 2m band. (Note that it has a 5W power rating which is fine for handheld radios but not more powerful transceivers.) DCI Digital Communications offers higher power filters but they are much larger in size.
Change Frequency
Sometimes a small change in frequency might help a bit if the interference is limited to certain frequencies. Another tip is to try another band. That is, if you are getting interference on 2 meters, you may find that the 70 cm band is better. Or vice versa. It all depends on the transmitters at the site.
73 Bob K0NR
The post RFI on SOTA Summits appeared first on The KØNR Radio Site.
Software-Defined Radio: Try Before You Buy? You Might Like It!
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.
[embedyt]https://www.youtube.com/watch?v=DHj917E1bKA[/embedyt]
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).
[embedyt]https://www.youtube.com/watch?v=YLBLHi441Zg[/embedyt]
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) ..
Check Out My New SDRplay RSPdx Software-Defined Radio Receiver – Live!
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:
[embedyt] https://www.youtube.com/watch?v=DHj917E1bKA[/embedyt]
73!












