Question T3C07 in the Technician Class question pool reads:

What band is best suited for communicating via meteor scatter?

1. 33 centimeters
2. 6 meters
3. 2 meters
4. 70 centimeters

The answer, of course, is B. 6 meters.

I make a big deal out of this question when I teach my one-day Tech classes because I think meteor scatter is probably one of the coolest things that Techs can do. Have I ever done it? Well, no, at least not yet.

Two months ago, I came across this video:

I also had a bunch of 75Ω coax that was installed back in 1985 when the house was built to distribute cable TV to the living room, bedroom, etc. I’ve never had cable TV in the nearly 25 years I’ve lived here, so I just cut a length from one of the cable runs. So, not only did the antenna look easy to build, I wouldn’t have to spend a dime on it.

Today, I finally got around to putting it all together. As you can see from the photo below, I used the military surplus fiberglass mast to get it up off the ground.

The photo below shows how I connect the loop  to the matching stub using a terminal strip.

Troubleshooting the antenna

When I first connected my antenna analyzer to the antenna, I was a little dismayed that the SWR was 14:1! I hadn’t expected it to be perfect, but I did expect it to be a lot lower than that.

The first thing I did was make sure that the wires were connected to the terminal strips properly. When that proved not to be the problem, I thought that maybe it was too close to my other antennas, so I moved it to the other side of the yard. That didn’t change a thing, either.

My next guess was that perhaps the coax was bad somehow, so I disconnected the matching stub and measured the SWR again. At 50.1 MHz, the SWR was now a much better 1.76:1. Since the feed point impedance of just the loop is supposed to be about 100Ω, I knew the problem was the matching stub.

In another video, I’d seen the coax used for the matching stub coiled around a PVC pipe. The theory behind this is that not only the stub matching impedances, but also acting as a choke. I didn’t have any PVC pipe big enough, so I simply coiled the 75Ω coax and taped it together. WRONG! When I uncoiled the matching stub, the SWR came down dramatically, measuring about 1.1:1 at 52 MHz. Down at the bottom of the band, where I planned on playing, it was a bit higher, but it was still less than 1.5:1, and that is easily handled by my IC-7610’s antenna tuner.

Of course, now that I have the antenna, the band is just dead. I’ve been monitoring for the last hour or so, with nary a signal received. That’s just how it goes with 6 meters, I guess.

Meteor scatter here I come

I think that to be more successful on 6 meters, I’ll need to make some improvements to the antenna. For example, I’ll have to figure out a way to make the connections more robust and maybe add a little wire to the loop to bring the resonant frequency down a little. I probably should get the antenna up a little higher, too.

Building this antenna has been fun, and even though I still  haven’t made any contacts, I’m looking forward to operating 6 meters in the future. Maybe I’ll even get lucky and make some meteor scatter contacts. Then, when I cover that question in class, I can say that I’ve operated meteor scatter and it’s pretty cool.

As a follow-up to the previous post, in which I discovered that the Sony SRF-59, though cheap to purchase, offered surprisingly good performance due to a rather creative and interesting receiver architecture. I did some reading up on external antennas to help pull in weak stations.  Among the Ultralight DX’ing crowd (those who DX the AMBC band with small, cheap receivers) FSL antennas are a source of great interest – they offer good gain and directivity in a small and portable package.  However, I had almost all the materials on hand to build a simple tuned loop and as, typically, I don’t pursue these things in too much depth, figured this would be the way to go.

First off, let’s get to grips with the rather complex schematic of this thing. The SRF-59 doesn’t have an antenna jack, so the external antenna will need to be coupled to the receiver inductively, which just makes the circuit diagram even simpler (at this point, it couldn’t really be any simpler) –

There are many different ways to construct a loop of this type. Big ones give more gain with deeper nulls, but space is at a premium for me and as this was an initial experiment, I decided to go for something modest in size.  You can use a cardboard box, plastic crate, or any number of things on which to wind the turns, but I opted to construct a frame specifically for the purpose.  Hardwood is nice, but I don’t have any woodworking tools. A trip to Michael’s craft store yielded a display of balsa and basswood in pre-cut and finished sizes. Balsa is very easy to cut, but is also very soft, and wouldn’t be very hard wearing in duty as a portable loop antenna.  Basswood is a little harder, but can still be cut with a sharp craft knife, so I decided to try a frame made form basswood. I bought 2 pieces of basswood pre-cut to 3/16″ x 3″ x 24″ and a length of 1/2″ square rod to strengthen the frame. At this stage, I have cut 2 slots in each of the 2 main pieces –

I slotted the 2 pieces together and glued 2 pieces of the square section to them with epoxy, to act as strengthening pieces. The square section was held in place with small clamps while the glue was setting. Here’s the finished result –

I wanted to have a rough idea how many turns would be needed, so found an online calculator for exactly this purpose.  I had a nice air-spaced variable capacitor that had been donated by a friend (thanks Jason!) With both gangs in parallel, it has a capacitance swing of 16 – 705pF.  This frame has sides equal to about 16.5″ in length and using the calculator, I figured that 10 turns, with 0.25″ spacing, should tune the AM BC band. Before winding the loop, I mounted the variable capacitor –

I split a length of narrow-gauge zip cord in two for the loop. Halfway through winding it, Sprat The QRP Cat bit clean through the wire while my back was turned, so I had to solder a new length on in order to continue winding. She also chewed a small part of the frame while I wasn’t looking. It’s a good thing I love that little kitty!

Here’s the finished loop –

The space between the windings is 1/4″, with a wider 1/2″ gap in the middle. This is in case I later decide to use a rod or piece of square section wood as a supporting mast – it can fit through that larger gap –

Another view of the completed loop –

Of course I was keen to try it out, so I switched the SRF-59 on, placed it close to the loop, tuned to a weak station, then tried tuning the loop and moving the receiver around for optimum coupling. Nothing I tried seemed to work and although I could tune the loop to resonate at the frequency I was listening on, it wasn’t enhancing the received signal at all. In fact, reception was better without it. This was all rather dispiriting and I was about ready to throw the towel in and think about adding a few parts to convert the loop to a novel crystal set receiver when, after taking some shots of it outside on my balcony (the 2 pictures above with the concrete on the floor, and the one below), I decided to set up the radio and try it there. It worked! (All the previous tests had been made in my apartment indoors).

For good inductive coupling between the loop and receiver, you want to orient the loop so that both it’s turns, and the turns on the ferrite rod of the receiver, are in the same plane.  The rod in the SRF-59 runs across the top of the case, so this is how it is oriented (you can also place it inside the loop) –

In the above picture, the loop will receive maximum signal from stations to the left and right of the picture (broadside to the winding) – and it does!  My test was only brief, conducted in the daytime, with signals that were of moderate strength. They were of such a strength that there was some noise and static when receiving them with just the radio. On placing the radio next to the loop and tuning it to resonance, all static and noise disappeared, yielding a more pleasant signal to listen to.  To make operation easier,  when orienting the loop for maximum signal, I rested the receiver on one of the diagonal arms in the frame. If the loop were on a stand, one of the arms would be horizontal.

My loop seems to tune well above the top end of the BC band, but doesn’t cover the bit from 530 to about 600KHz.  A fixed capacitor across the variable should bring the tuning range down a bit.  I’ll fiddle around with it in the next few days. I may also make a recording if the spirit moves me EDIT – I did. See below.

I already had the wire and variable capacitor, so this loop cost me $8.58 in wood from the craft store. The SRF-59 receiver cost me $6.50 inc shipping from eBay, so my complete AM BC band DXing set up set me back a whopping $15.08. I like the kind of fun that can be had for such a small outlay

This afternoon, I went out onto my balcony and made a short recording of KZSF in San Jose.

The recording starts with the SRF-59 receiver without the loop, then I place the receiver inside the loop, which has been pre-tuned to resonance and oriented in the direction for maximum signal. I remove the receiver, and then place it back in the loop for comparison. KZSF is not a DX station from my location in Oakland. It is a 5KW station in San Jose – just 40 miles away. It is entirely possible that I could have found a nearby position from which to get a better signal on the receiver without the loop, but this recording was made to show how a loop such as this can provide a meaningful and useful boost to a marginal signal.

8/03/2024 Update – I recently received an email from James W8FDV. He writes, “Made one as close to yours as possible. Works well”. That looks like the Sony SRF-39FP Federal Prison clear version that you are using it with James. Your FB loop antenna project reminds me that it’s been a while since I’ve used mine. I should take it down from the shelf and give it a spin. Hope yours continues to work out well for you OM!

3 years ago I did a review of the Chameleon Tactical Delta Loop antenna. At that time I had a mediocre feeling towards it. But taking a 2nd look, I am totally impressed on how this amazing antenna performs on the upper bands.

Chameleon CHA TDl (Tactical Delta Loop Antenna): https://chameleonantenna.com/shop-here/ols/products/cha-tdl
Tripod Quick Release Plate: https://amzn.to/3IBaAJI
Chameleon 3/8 to 1/4 inch thread tripod adapter: https://chameleonantenna.com/shop-here/ols/products/cha-tripod-adapter
Yaesu FT-891 transceiver: https://amzn.to/3RSg4DO
Heil Ham Radio BM-17 Dual headset: https://heilhamradio.com/product/bm-17-2/

How I record my contact audio: https://youtu.be/tOqzZPphE7k
My headset trigger switch: https://youtu.be/b5Wu8BlrSF0

As a bonus, patrons can view the full, unedited phone contacts for this Parks on the Air activation. Visit my page on Patreon for details: https://www.patreon.com/kb9vbrantennas

I do return QSL, if you made a contact with me and would like a QSL, please send me one. Return postage not necessary, but always appreciated. As they say, KB9VBR is ‘good in the book.

Links may be affiliate links. As an Amazon Associate, I earn from qualifying purchases. This does not affect the price you pay.

Like what you see? You can leave me a tip:
https://www.paypal.me/kb9vbr

Become a patron! Unlock exclusive content at: https://www.patreon.com/kb9vbrantennas

Support Ham Radio Q&A by shopping at Amazon: http://amzn.to/2kO6LH7

The post Amazing Performance: Chameleon Tactical Delta Loop Antenna Revisited appeared first on KB9VBR Antennas.

It’s a POTA road trip! I head out to activate three new to me parks while using a different antenna at each one. Ride along with me for an epic Parks on the Air activation as we find out which one will be the best

As a bonus, patrons can view the full, unedited phone contacts for this Parks on the Air activation. Visit my page on Patreon for details: https://www.patreon.com/kb9vbrantennas

I do return QSL, if you made a contact with me and would like a QSL, please send me one. Return postage not necessary, but always appreciated. As they say, KB9VBR is ‘good in the book.

Coffee and Ham Radios Apollo End Fed Half Wave: https://coffee-and-ham-radios.square.site/product/cahrtenna-apollo-end-fed-half-wave-/8
Chameleon CHA F-Loop 3.0 Magnetic Loop: https://chameleonantenna.com/shop-here/ols/products/cha-f-loop-30
213 inch whip antenna: https://amzn.to/3O3Bvkm
Feather Flag Base: https://amzn.to/3O6O7al
Antenna mirror mount jaw clamp: https://amzn.to/48yzRPL
3/8×24 SO-239 stud mount: https://amzn.to/3Sjre69
Aluminum window screen: https://amzn.to/3Sii0Ho
Faraday cloth: https://amzn.to/3vCru7r
Yaesu FT-891 transceiver: https://amzn.to/3RSg4DO
Heil Ham Radio BM-17 Dual headset: https://heilhamradio.com/product/bm-17-2/

How I record my contact audio: https://youtu.be/tOqzZPphE7k
My headset trigger switch: https://youtu.be/b5Wu8BlrSF0

Bill Cross was a fascinating ‘character’ in pioneer history: https://www.wisconsinhistory.org/Records/Newspaper/BA1204

Links may be affiliate links. As an Amazon Associate, I earn from qualifying purchases. This does not affect the price you pay.

The post Which is best? POTA Antenna Showdown in the Wild appeared first on KB9VBR Antennas.

In the proper sense, small magnetic loop antennas are not considered a compromise. With a properly sized loop, they have the efficiency of a properly mounted half wave dipole*. The Chameleon F-Loop 3.0 antenna unleashes that power with a magnetic loop design that is easy to deploy and offers a broad range of frequency support between 10 and 80 meters on the HF bands.

Chameleon CHA F-Loop 3.0 Magnetic Loop Antenna: https://chameleonantenna.com/shop-here/ols/products/cha-f-loop-30

Konsait Black Camera 323 Quick Release Plate with Special Adapter (200PL-14) for use with Manfrotto tripods: https://amzn.to/49fTAEo

(*) An Overview of the Underestimated Magnetic Loop HF Antenna
Leigh Turner, VK5KLT, 2015 (accessed February 12, 2024)
https://www.nonstopsystems.com/radio/pdf-ant/article-antenna-mag-loop-2.pdf

Magnetic loop antennas consist of three components. The first, and most noticeable is a large primary loop. This loop circumference is typically within ⅓ to ⅛ the operating frequency range of the antenna. Inside this primary loop is a smaller conducting loop. RF energy is fed into the conducting loop and the electromagnetic coupling between the two are what creates the RF radiation. The third part is a tuning capacitor, which is connected to the large primary loop. Loop antennas have a low radiation resistance and the purpose of the capacitor is to eliminate reactance so that the loop becomes a resonant radiator. Since it is a resonant antenna, no antenna tuner or transmatch is required.

Since magnetic loop antennas have a low radiation resistance, high currents flow through the primary loop. These current flows are what radiates the RF energy in the form of electromagnetic coupling. These current flows are a limiting factor of magnetic loop antennas as if you give them too much transmit power, the capacitor will arc and short circuit.

With that said, magnetic loop antennas are a great choice for QRP or lower power operating and we’ll talk about those benefits and features in a bit, but first, let’s look at the Chameleon F-Loop kit.

Tuning a magnetic loop antenna

Now we get to the fun part, tuning your F-Loop antenna. Magnetic loop antennas have a very high Q, or quality factor. What that means is that their 2:1 bandwidth is very sharp and pronounced. As you go lower in frequency, the bandwidth shrinks. This loop will have 210 KHz of bandwidth on the 10 meter band, but on 80 meters, that bandwidth drops to 6 KHz. This is due to the function and size of the radiating loop. To a certain degree, a larger loop will give you more bandwidth on the lower frequencies, but even at that there are limits. Basically if you want to change frequencies, you will have to readjust the antenna.

There are two methods of adjusting the loop. The first is to use an antenna analyzer. Connect the analyzer and turn the tuning knob until you see a dip on the meter. As you are tuning, you will notice that touching the unit will slightly detune it, so as you are tuning, you will need to step away from the unit to get a more accurate reading. The knob is very sensitive and the 6:1 reduction drive lets you do precise adjustments. When you get in the ballpark, it will take very slight movements of the knob to hit the sweet spot.

The second method to tune the loop is to listen to your transceiver. As your turn the knob, you will hear the noise level increase and then decrease. This point of maximum noise is the sweet spot of the antenna and the result of your tuned frequency. After adjusting for maximum noise, make a test transmission to check the SWR and make any minor adjustments until you are at the minimum. You may not always hit 1:1 match, but anything under 2:1 SWR is fine and the antenna will operate well.

With magnetic loop antennas, you should never use a tuner or transmatch. These antennas are designed to work without a tuner and should only be adjusted to their resonant frequency using the tuning knob.

Once the antenna is adjusted, go ahead and transmit. If you need to change frequency, you will need to readjust the antenna.

My experiences with magnetic loop antennas

So what are my experiences with the F-Loop magnetic loop antenna? Generally, I had a lot of fun with this antenna. It sets up and tears down quickly, it is reasonably efficient, and by virtue of its use of the H or magnetic fields, it is highly resistant to man made noise. That makes these antennas great choices if you are in an urban environment or a residential area that is prone to RF interference.

I took this antenna out for a few Parks on the air activations to test its performance. This antenna paired really well with my Yaesu FT-817 QRP transceiver, but I would think this is an excellent companion also to the Icom IC-805, Elecraft KX series or the Xiegu G90 or 6100 low power rigs.

Magnetic loop antennas are often characterized as QRP antennas and the F-Loop can handle up to 25 watts sideband and 10 watts CW or digital. If you use more power than that, the air capacitor inside the tuning unit will start to arc. And therein lies the misconception that magnetic loop antennas are poor performing antennas.

In reality, they are not. A magnetic loop will work just as well as other antennas. At their best, a magnetic loop on the upper bands is comparable in performance to a dipole. At their worst, they are 6 dB or 1 S unit lower than an optimized three element beam. Which brings me to my on air test.

Looking at the data, the magnetic loop performed quite favorably when compared to my customary ¼ wave vertical antenna. On FT8, the signal reports where pretty equivalent. Using my Yaesu FT-817 set to 5 watts, I ran both antennas on the 20 meter band for about 45 minutes each and in that time period received about 18 contacts on each antenna. With the magnetic loop I gave an average signal report of -9 and received a report of -11 dB. With the vertical, I gave a signal report of -13 and received a -12 dB. To me, that isn’t much of a difference. In fact, the only difference that I can spot is that in looking at the maps of contacts, the distances achieved with the vertical were further than the magnetic loop. But that could be attributed to the vertical antenna propensity for having a lower RF angle of radiation.

So what are the down sides of Chameleon F-Loop antenna. I don’t think there is really anything negative about this antenna on it own, this is a highly engineered and well constructed piece of equipment. But the negatives relate to magnetic loop antennas in general. First is its low power capability. I know a lot of people aren’t into QRP operation so the 25 watt limit on sideband may be a turnoff. Chameleon does offer an optional power compensator that allows you to use up to 60 watts sideband with the loop, but still these are categorized as low power antennas.

The second downside is the relatively narrow bandwidth. If you change frequencies, you will need to re tune the antenna. You certainly have more bandwidth on 10 and 15 meters, but 20 meters and lower, the bandwidth approaches paper thin ranges. That can be great for rejecting adjacent noise and signals, but if you are the hunt and pounce type of person, you will find the bandwidth highly limiting.

I think these two limitations of magnetic loops really lend themselves to digital and CW operation. The weak signal modes like FT8 and the narrow bandwidth of CW really make these antennas shine. And being that we are at the peak of the solar cycle, we can also take advantage of their enhanced performance on the higher HF bands.

Since magnetic loop antennas also exploit the H or magnetic field, they can be successfully used indoors with a minimal performance loss. H fields have better penetration through walls and glass, so If you live in an apartment, condo, or have HOA limits, this may be the type of antenna that gets you on the air at home. In a high RF noise environment, their enhanced signal to noise ratio will also be of a benefit, and you may be able to hear things that you miss with other antennas.

Links may be affiliate links. As an Amazon Associate, I earn from qualifying purchases. This does not affect the price you pay.

Like what you see? You can leave me a tip:
https://www.paypal.me/kb9vbr

Become a patron! Unlock exclusive content at: https://www.patreon.com/kb9vbrantennas

Support Ham Radio Q&A by shopping at Amazon: http://amzn.to/2kO6LH7

Timestamp
00:00:00 Introduction
00:00:30 Chameleon F-Loop 3.0 Magnetic Loop Antenna
00:01:02 How do magnetic loop antenna works
00:02:26 Chameleon F-Loop 3.0 Kit Options
00:04:38 Assembling the Magnetic Loop Antenna
00:07:04 Tuning your Magnetic Loop Antenna
00:08:59 Chameleon F-Loop 3 80 meter band
00:09:51 Personal Experience with the F-Loop
00:14:15 Magnetic Loops are NOT compromise antennas
00:16:35 Who are magnetic loop antennas good for

The post Discover the Power of Magnetic Loop Antennas: Chameleon F-Loop 3.0 appeared first on KB9VBR Antennas.

This antenna modelling session came about after a conversation with Michael, DK1MI on the Matrix. I believe the antenna design was originally done by Artur, M0PLK with reviews being on EHAM.

The antenna takes the form of a simple inverted triangular loop with a 5.8m flat top and two diagonals each 5.6m long coming down to a point. The antenna is fed in the centre of the flat top with 450 Ohm open ladder line and a 4:1 Balun. This antenna will require an ATU on all bands as the modelling shows a very wide range of impedances at the feed point.

The design seems to suggest using two fixed aluminium tubes with the wire fed up through them for the two diagonal elements of the antenna however, it would probably be easier to use a pair of collapsable fibre glass poles (Not Carbon fibre) with the wire attached via some clips or tape.

I decided to model the antenna with the top horizontal wire 10m above ground putting the point of the triangle 5.2m above ground. I felt this was an achievable height for most HAMs. Lowering the antenna will raise the resultant angle of maximum radiation on all bands.

Looking at the 2D Far Field Plots (2DFFP) the antenna radiates through the loop as expected with a higher radiation angle on the lowest band and the lowest radiation angle on the highest band. The antenna is of course bi-directional and so could be rotated just 180 degrees to obtain global coverage.

On the 30m band the antenna has a very high angle of maximum radiation making it ideal for short distances. There is a little gain to be had at 25 degrees however, this is nowhere near the maximum but, will possibly aid working longer distances. A maximum gain of 5.31dBi is obtained at 72 Degrees on the 30m band.

On the 20m band the 2DFFP is fairly similar to that of the 30m band but, with 5.57dBi gain at a lower angle of 34 Degrees. This will provide excellent results on medium distance contacts and reasonable results on the long haul.

Once above 14Mhz things start to get more interesting. From the 17m band upwards the radiation pattern changes quite drastically and starts to provide some excellent gain at relatively low angles. This will improve the antenna’s DX performance considerably on the higher bands.

Looking at the 17m band the angle of maximum radiation is now down to 26 degrees with a gain of 7.64dBi. At 12 degrees there is a gain of 4.59dBi. This radiation pattern will make this antenna ideal for the medium to long haul contact with very little interference from NVIS signals.

The 15m band follows the trend with the angle of max radiation now down to 22 degrees with a max gain of 8.54dBi. Even at 10 degrees there is a gain of 5.34dBi which will be very welcome for DXing. There is slightly more near vertical incident skywave (NVIS) radiation on the 15m band and so the antenna should provide short, medium and long haul contacts with the latter being favoured.

Moving up to the 12m band the angle of maximum radiation now comes down to 18 degrees with a gain of 8.61dBi. There is also 5dBi of gain to be had at 8 degrees which is ideal for DXing. Unfortunately there is slightly more NVIS radiation on the 12m band than there is on the 15m band. I’m sure with a little change in height this could be reduced such that the antenna provides only low angle radiation.

Finally we reach the 10m band, this is where the antenna has the lowest angle of maximum radiation. With 8.56dBi gain at 16 Degrees, 5.59dBi at 8 degrees and a much reduced NVIS radiation. This antenna should be excellent for the long haul on 28-29Mhz. (It would also make an excellent 11m/CB antenna).

It’s interesting to note the similarities between this multi-band delta loop design and my Bi-Directional Slot Fed Antenna design. They both exhibit very similar radiation patterns and gain figures with the Slot Fed Antenna providing slightly more gain and an even lower angle of maximum radiation on the supported bands.

Overall this easy to construct multi-band delta loop antenna would be ideal for the HAM that just wants a single antenna for 30m and upwards or is looking to go portable. The only disadvantage is that a good Remote Auto ATU is required to provide matching of the antenna to the 50 ohm coax at the feed point. Something like the LDG RT100 would be an ideal ATU choice for this application and would remove the losses caused by having a high SWR on the coax feed to the antenna.

Using an ATU in the radio in the shack isn’t going to provide the same results as the coax cable from the antenna to the shack will become part of the antenna and will be detrimental to the antenna performance. It will also create high losses on the coax feed to the antenna due to high SWR being present over the length of the coaxial feed.

I’ve had this antenna model for ages now but, never got round to putting it onto the website until Alex, GM5ALX was talking about making one the other day whilst chatting on the QO-100 satellite.

The 20m band delta loop follows exactly the same design principles as all the other delta loop designs I’ve already put on the website. They are designed such that they present a 50 ohm impedance at the feed point and thus have no requirement for complex impedance matching circuits/transformers.

The dimensions for the antenna are as follows:

Wire 1 – Horizontal exactly 1m above the ground for its entire 10.2m length.
Wires 2 & 3 are exactly 6.18m long each with the top being 4.5m above the ground.

The 3D far field plot shows a typical delta loop radiation pattern with the maximum radiation through the loop and a deep null in the centre.

The 2D elevation plot shows that the antenna will give a maximum gain of -0.79dBi at 30 degrees when used over average/poor soil types. If like me you use your Delta Loop antennas on the beach then the antenna will present considerably more gain as it will benefit from the salt water reflection.

If you want to lower the angle of maximum radiation and increase the gain over average ground just raise the antenna up so that the top is around 7m above ground. This will give a much lower angle of radiation and improve the gain figure by 2-3dBi. Don’t forget that if you raise the antenna the point of resonance will also rise in frequency and so you may need to shorten the wires a little to get the point of resonance back to where you want it.

The SWR plot shows that the antenna will have a fairly wide bandwidth and match to 50 ohm coax extremely well. The antenna is designed to be fed in one of the lower corners via a 1:1 balun for best results.

Summary:

Total Wire Length: 16.38m
Horizontal Wire Length: 10.2m @ 1m above ground
Diagonal Wire Lengths: 6.18m
Wire Dia: 2.5mm
Height at Centre: 4.5m
Feed Type: 1:1 Balun in bottom corner (Can use coax if necessary)
Impedance: 50 Ohm
SWR: <1.5:1 at resonance

This is a 15m band delta loop design that I’ve put together as requested by Wim, PE1PME.

The 15m band delta loop follows exactly the same design principles as all the other delta loop designs I’ve already put on the website. They are designed such that they present a 50 ohm impedance at the feed point and thus have no requirement for complex impedance matching circuits/transformers.

The dimensions for the antenna are as follows:

Wire 1 – Horizontal exactly 1m above the ground for its entire 7m length.
Wires 2 & 3 are exactly 4.12m long each with the top being 3.18m above the ground.

The 3D far field plot shows a typical delta loop radiation pattern with the maximum radiation through the loop and a deep null in the centre.

The 2D elevation plot shows that the antenna will give a maximum gain of 1.5dBi at 26 degrees with useful gain at lower angles.

The SWR plot shows that the antenna will have a fairly wide bandwidth and match to 50 ohm coax extremely well. The antenna is designed to be fed in one of the lower corners via a 1:1 balun for best results.

Summary:

Total Wire Length: 15.24m
Horizontal Wire Length: 7m @ 1m above ground
Diagonal Wire Lengths: 4.12m
Wire Dia: 2.5mm
Height at Centre: 3.18m
Feed Type: 1:1 Balun in bottom corner (Can use coax if necessary)
Impedance: 50 Ohm
SWR: <1.5:1 at resonance

The Airspy YouLoop is a no tune, broadband, small footprint, affordable LF to HF receive antenna that works indoors. Its modular construction facilitates experiments to understand where the Möbius inspired electrical design provides benefit.

The post Airspy YouLoop LF/MF/HF Möbius Receive Antenna appeared first on Ham Radio . Magnum Experimentum.

Add amateur radio to your beach trip keeping in mind family life balance.

The post Beach fishing for QSOs with an STL appeared first on Ham Radio . Magnum Experimentum.

Continue reading "Inside the MLA-30 Active Loop Antenna"