Amateur radio antennas, circuits, techniques and related topics. By Peter Parker VK3YE/AK3YE.
Newer material appears at https://vk3ye.com and https://youtube.com/vk3ye .
If you don't have much horizontal space to string up a wire antenna you could consider a vertical. But that requires significant attention to ground radials. If you can't arrange them and still wish to get on air you could try a coaxial cable magnetic loop. That's super-simple but you may need a capacitor box to bring it to resonance and match it to the transceiver. This video describes my recent experience of one.
PS: I've now written six books on various aspects of amateur radio. Whether you experiment with antennas, enjoy QRP or are starting out in radio there's a book for you. Find out more here.
A super-handy material for radio projects is plastic corflute (or coroplast) material. It's a super-light super-strong sandwich ideal for many applications. For example coil formers, spreaders for antenna feedlines and even enclosures for projects. A few ideas in this video here:
PS: Are you returning to amateur radio after a spell away? If so this book might be just the ticket. It fills you in on what you missed and brings you up to speed with activities modern hams enjoy. Available in electronic or paperback form you can find out more here.
We've been talking about microphones a lot lately. Eg with regards to microphones for the FT817. And just a few days ago for FM handheld transceiver microphones. I make no apology as audio is important. So here's yet another microphone video where you can hear the difference a good one can make.
PS: Heard about my new book? It's Australia's own amateur radio handbook. Available in both electronic and paperback form, you can find out more here.
If your 6m receiver isn't doing anything on early weekend mornings you could do worse than to leave it on 50 MHz hooked up to your computer with the free WSJT-X 2.0 program running. Even with a very simple antenna you might get some interesting distant callsigns pop up thanks to the MSK144 mode and the communication enabled by meteor scatter. Find out more here:
PS: I've now written six books on various aspects of amateur radio. Whether you experiment with antennas, enjoy QRP or are starting out in radio there's a book for you. Find out more here.
After all there was no sign of the widely requested and expected increased power output limits and frequency privileges. Hence our Foundation licensees will continue with ten watts and our Standards will still not have 50 MHz.
However what all hams did get were freed up mode restrictions. This means that, provided power density is kept to under 1w per 100 kHz, amateurs can experiment with wideband digital modes. And Standard hams get to transmit amateur television on their UHF allocations.
Foundation licensees gain the most. Removing mode restrictions means that they can enjoy digital modes. This will make their 10 watts go better and further. However their four letter callsign suffixes may be a challenge for some mode formats.
Also gone are restrictions on building your own transmitting gear, computer control, sending computer-generated Morse, showing others amateur radio and connecting to the phone system. These restrictions made our Foundation conditions quite tight.
A three minute video summary on what's changed and what hasn't is below.
PS: Heard about my new book? It's Australia's own amateur radio handbook. Available in both electronic and paperback form, you can find out more here.
A super simple idea with just a few parts. Handy for incorporating in existing gear.
PS:Enjoy these well-reviewed books on various amateur radio topics. They're available for under $US 5 each in electronic form. Or you can get them in paperback. Visit VK3YE Radio Books to find out more.
One of the handiest pieces of test gear I've owned is this small LCR and impedance meter. I did a review about a year ago. Watch it here.
The meter is handy for the builder, the repairer and the person who just wants to learn more about LCR. I discuss all this in a bit more detail here. It certainly gave me new insight into these topics.
PS: Want to know more about QRP? You need Minimum QRP. It's a top selling manual on success with low power amateur radio. Available in ebook or paperback formats you can find out more here.
My magnetic loop videos have always been popular so here's another. It's made from thick speaker cable. It's good in that all the connections are soldered but poor in that the wire won't be as good as solid copper. But the loop is quite light and portable.
Here I try it on various frequencies between 7 and 28 MHz from both home and away. SSB was unsuccessful but digital modes worked, including a JS8 contact made on 28 MHz when the loop was indoors.
PS: Want to do more with amateur radio? 99 things you can do with Amateur Radio is full of ideas. Available as a low-cost ebook or in paperback, you can find out more here.
Yesterday we discussed improving your signal from your handheld by adding an extension stick. Good audio is also important. If it's bad you can have a strong signal but still be hard to understand. Especially if the station you're trying to work is in a noisy environment.
Here I try different microphones with a cheap handheld with very different results. In some cases the microphones are sloppily built so the element doesn't always line up with the hole. So it sometimes pays to open them up to have a look inside.
PS: Want to get even more from your QRP gear? You need Minimum QRP. It's a top-selling manual for all things low power amateur radio. Available in ebook or paperback, find out more here.
Want to get better results from your handheld transceiver? Hold it up high. Want even better results? Go even higher. Video presents some ideas on this.
PS: I've now written six books on various aspects of amateur radio. Whether you experiment with antennas, enjoy QRP or are starting out in radio there's a book for you. Find out more here.
Antennas don't last forever. They can deteriorate over time. Connections can become bad, metals can oxidise and baluns can fill with water. Portable antennas are particularly susceptible. Here's a video on inspecting and maintaining a magnetic loop.
PS: Want more small antenna ideas? Many are in Hand-carried QRP antennas. Thousands sold. Favourably reviewed. Available in electronic or paperback. Find out more here.
Have a million projects on the go and little time to finish them? This video could help. It's 8 tips to build your radio projects faster.
PS: Have you given amateur radio a break away but are now returning to it? This book could help. "Getting Back into Amateur Radio" is the low-cost ebook for the returning ham. And it's available in paperback as well. Find out more here.
A week ago we discussed magnetic loops for 144 MHz. Today I'll demonstrate mine. I'm using WSPR transmitting from the middle of the city. There's buildings all around me but I'm still getting through. Demonstration in this video.
PS: WSPR is just one aspect of stuff you can do with QRP or low power amateur radio. For ideas on other factets of amateur radio that low power works with, check out Minimum QRP. Available in ebook or paperback thousands have been sold around the world.
I was browsing the local charity shop and on the shelf for two dollars was this 1990s-era solar powered radio. How could I resist? So I didn't. Here's how the set works and what's inside.
PS: I've now written six books on various aspects of amateur radio. Whether you experiment with antennas, enjoy QRP or are starting out in radio there's a book for you. Find out more here.
Many of us have used the FM satellites. They're are basically an orbiting single channel repeater. All you need is a couple of cheap handhelds (and preferably some small yagis) and you can have contacts through them.
However their pass times are short and you can only have a single contact at a time. This is where SSB satellites come in. They have a linear translator. Thus they can support multiple contacts simultaneously. The only problem is they need two SSB-capable transceivers. And you need to retune to account for doppler shift.
CW is a bit easier. You just need one SSB receiver to receive the downlink. In a pinch you can use a cheap handheld (keyed) to send slow morse. And a bit of frequency drift is OK as it makes the signal less readable than what would happen with an SSB signal.
I haven't had a contact in this fashion. But I have done some tests to prove it would work. Here's a video showing it.
PS:Into low power amateur radio? Minimum QRP is the top-selling manual on the equipment, antennas, operating and strategy of successful QRP operating. It's available for under $US 5 each in electronic form. Or you can get a paperback version. Visit VK3YE Radio Books to find out more.
Transmit audio is critical for success with low power. Punchy audio from a QRP rig can be more readable than muffled audio from a higher power transmitter. The FT817/8's stock microphone isn't the best. But you can easily modify it. The videos below show what I did with some great results reported.
PS: Want to get even more from your QRP gear? You need Minimum QRP. It's a top-selling manual for all things low power amateur radio. Available in ebook or paperback, find out more here.
The China boom and online ordering has made test gear incredibly cheap for making simple electronic measurements.
But before that it was fairly expensive. And many hams built their own test gear.
This is something I put together in the early '90s to measure small values of inductance such as required in RF circuits.
For what you can do with more sophisticated test year you may wish to read my earlier post here where I go into inductance, capacitance and reactance in a bit more detail.
PS: I've now written six books on various aspects of amateur radio. Whether you experiment with antennas, enjoy QRP or are starting out in radio there's a book for you. Find out more here.
This rig breaks one of my slogans for hombrew gear: "Frequency agility is king". Still, especially if you've got a book to read between CQ calls, operating can be a fun. And you'll get a kick out of making contacts with a rig you built yourself.
The Knobless Wonder is a single frequency crystal controlled SSB transceiver. The fortunate availability of 7 MHz band crystals means that you can do the SSB filtering on your operating frequency. This simplifies circuitry as there's fewer frequency conversions involved. And quite a few people around the world have built it.
Interested? Visit my Knobless Wonder Page for more of a description, videos and links to others who have built it.
PS: Returning to amateur radio? Want to know how to pick up from where you left off? This top-selling book will get you up to speed. Available in electronic or paperback you can find out more here.
You don't need many parts to receive SSB signals on HF. But sometimes performance can be compromised. Here I talk about a simple 7 MHz receiver and RF breakthrough that simple gear can sometimes suffer.
PS: Looking for something new to do in amateur radio? Look no further. 99 things you can do with amateur radio has stacks of ideas. Available in both ebook and paperback formats you can find out more here.
Magnetic loops are normally thought of as the type of HF antenna you'd use if you've got not space for something that's full size. However they can also be used on 2 metres. As I write this I'm testing one indoors. So far stations have detected me at 50km distance with many dB to spare. I'll do a video on it eventually.
My loop is pretty close to a copy of this one by VK5BR. My material was stiff copper wire about 3mm diameter instead of the original 1/4 inch copper tubing. But my length is about the same. As is said in the article if you go any longer you'll have difficulties resonating with the variable capacitor. If you want to see the original Amateur Radio magazine article you'll find it here.
Here's a loop by IW5EDI. There's few words but the pictures should give an idea. I really like its robust construction.
Finally, this is a dainty little loop by M0UKD. It should only take a few minutes to make - it's just soldering some pieces of stiff wire together. It could make a good attic antenna. But I'd use a better trimmer for more than QRP power levels. Scroll down for other loop ideas.
A well-built loop should give close to a dipole's performance. However its bandwidth will be narrow. It won't be so good for repeater operation due to the 600 kHz offset (you'd need to optimise the loop on transmit and your receive sensitivity will be down). But for SSB or digital modes it will work well. Note though that it will be horizontally polarised so you'd need to tilt it 90 degrees for the vertical you'd need on FM.
PS: Want more small antenna ideas? Many are in Hand-carried QRP antennas. Thousands sold. Favourably reviewed. Available in electronic or paperback. Find out more here.
A short video on a small repair I did to a previously reliable QRP antenna coupler.
There's a few lessons in this.
Most notable is that components can sometimes partially fail and become intermittent. Such faults can't necessarily be picked up by simple multimeter tests that would otherwise suffice most of the time.
Also it's worth rethinking the use of small RF chokes as inductors even in QRP antenna couplers if you're using them to run continuous duty cycle digital modes as I believe it was them that caused the fault. Possible substitutes include going back to iron powder toroids like the T50-2 or T50-6.
PS: Want to know more about QRP? You need Minimum QRP. It's a top selling manual on success with low power amateur radio. Available in ebook or paperback formats you can find out more here.
The benefit of doing amateur radio on public transport is you have both hands free and you can pay full attention to your radio contact rather than having to concentrate on the road. The main disadvantage is you're very restricted with your transmitter power output and antennas. And if it's crowded you might not wish to operate at all.
Here are some videos where I try various modes of amateur radio in public transport.
2 metres FM. Here I'm in northern Tasmania. Having great results with 2m FM from inside a coach with a modified indoor TV antenna.
HF WSPR from inside a bus.
More HF WSPR success from inside a bus.
Because it's an efficient mode and its users often have excellent antennas, 2m SSB can do quite well. Also don't overlook the possibilities of modes like FT8 or JS8. You will need a horizontally polarised antenna for these.
A little while ago I did a test using the JS8 mode with Wade VK1MIC who was demonstrating it to a meeting of the Canberra Region Amateur Radio Club. 5 watts on 80m was more than enough to make it across the 500km path to VK1.
I didn't have my camera set up. But Wade did. His video is below.
Watch it to learn more about JS8 and its features.
If you haven't downloaded the free JS8Call software you really should to give this mode a go. It's fantastic for QRP. And, unlike FT8 you can have real keyboard conversations and even leave messages for people.
PS: With six titles now available, there's sure to be something of interest. All books are available in ebook or paperback. Lean more here.
CW, SSB and the common digital modes aren't the only use for QRP. Slow Scan TV can work as well. You can download software (like MMSSTV) or use a mobile app to send audio to your SSB transceiver. If you're not doing a test with someone on the other end you could monitor your signal with a live SSTV cam.
Your QRP signal will be a bit grainer than those running high power. Tips to minimise the effects of this including using high contrast slides and using a good solid font for your callsign. Repeating your callsign can help defend against interference bursts. It also helps to use a slower transmitting speed.
Below is an example SSTV webcam. I was running 5w on 80m from about 300 km away.
Below is an account of a milliwatt test with VK4VJR
This one's only a couple of days ago. It's an SSTV contact over 450km in the middle of the day on 3.5 MHz.
Give SSTV a go. Even with QRP. Let me know the results you get in the comments below.
PS: Into low power amateur radio? Minimum QRP is the top-selling manual on the equipment, antennas, operating and strategy of successful QRP operating. It's available for under $US 5 each in electronic form. Or you can get a paperback version. Visit VK3YE Radio Books to find out more.
Want a good home station antenna for two metres FM? And with bonus 6m capability? Look no further. This vertical extended double zepp works a treat, with better gain on 2m than many other antennas. A description and demonstration is in the video below.
PS: Heard about my new book? It's Australia's own amateur radio handbook. Available in both electronic and paperback form, you can find out more here.
Many will know of Alf Traegar's pedal radio that was so central to the success of the Royal Flying Doctor Service. Developing that was a major feat given the power-hungry valves available at the time.
Solid state parts has made human-powered radio equipment easier. I built a simple QRP crystal controlled CW transceiver in the case previously used by a hand-cranked torch. It was based on the well-known Oxo found in G-QRP publications. I kept the generator but removed the light. It has been heard over 700 km away. Here are some hand-cranked power videos.
Have you built a human powered transmitter? How far did it go? Please leave your comments below.
PS:Enjoy these well-reviewed books on various amateur radio topics. They're available for under $US 5 each in electronic form. Or you can get them in paperback. Visit VK3YE Radio Books to find out more.
Yesterday I was invited to present to the G-QRP Club's annual convention via video link. I covered a range of topics including QRP in Australia, homebrewing, magnetic loops, answers to questions and more. Here's the video.
PS: Want to know more about QRP? You need Minimum QRP. It's a top selling manual on success with low power amateur radio. Available in ebook or paperback formats you can find out more here.
News of Icom's new IC-705 QRP 160m-70cm rig has just come out. It was displayed at the Tokyo Hamfair. All I've done is read various accounts so I don't have personal experience of it. Will I get one? Probably not. I don't think it suits my style of beach, salt and sand portable operating (below).
There's chatter on QRZ forums. In no time an IC-705 Facebook group was set up. Already that's providing some answers to questions that portable QRPers would want to know. Eg receive current consumption. More on that later.
So what is the IC-705? You could say it's a sort of cross between an FT-817/8, an Elecract KX3 and Icom's own IC-7300. Like the FT-817/8 it has 160m - 70cm all mode coverage (but with a wider range receiver). It inherits its 'brick' type size and shape from the Elecraft. And the front panel and display looks a lot like an IC-7300. In fact from a distance they look the same except when you look at the distance to the rear (bottom) panel which is very short. And, more substantially it has DSP architecture like the IC-7300.
The cost is likely to be nearer to that of the Elecraft than the FT-818. But if you already have the very popular IC-7300 then you might want a junior lookalike to use in the field. And if you want a bigger screen and likely better receive performance compared to your ageing FT-817 then you might wish to go for the IC-705 if you value the VHF/UHF coverage that the Elecraft lacks. The microwave crew might also consider it for driving their transverters (especially if they're used to the IC-9700 at home).
What other things are worth knowing? The IC-705 has lot of computer and network connectivity stuff that other QRP rigs don't. Even Bluetooth (that apparently makes everything better!). People will like the top-facing speaker. Although for a harsh environment people will be looking to see whether its holes attract sand, something I've always been dubious about the 'Swiss cheese' Elecraft.
There's only one antenna socket on the Icom. That's a big minus for VHF/UHF contesters compared to the FT817/8. With the latter you can have a 2m beam on one socket and a 70cm beam on another and never have to switch. An understated benefit. Also there seems to have no inbuilt antenna coupler, which the Elecraft KX-3 has. It's not hard to make your own but for people who want an all-in-1 package for use with end-fed wires it could be a deal breaker.
Power consumption. That's important for the portable QRPer. Surely that big display and the DSP would use a lot of juice. All I could find was a note on the Facebook group that says it's about 1/3 amp on receive. That puts it similar to the FT-817/8. Not outrageously high but not low either. On this the Elecraft scores better with drain around the 150 mA mark. The Icom's transmit power output is 10 watts - a shade higher than the FT-818's 6 watts but less than the Elecraft's 15w.
The IC-705 won't be out for a while. But I can see that it could be attractive to some. On a price basis it's nearer to competing with the Elecraft but on a band capability basis it might take some market share away from the FT-818 (which despite the new model number is only a slightly altered FT-817 from 18 years ago).
What do you think? What will be your next big QRP purchase? Will you wait for the IC-705, get something else in the meantime or keep going with what you've got? Please leave comments below.
PS: Having a QRP rig like the IC-705 is great but how do you get the most from it? That's why you need Minimum QRP - the world's top selling manual on success with low power amateur radio. Available in ebook or paperback formats you can find out more here.
