Tagged: antenna

JR Magnetics Small Ultra Wide Band 750 MHz to 6 GHz Antenna for SDRs on Kickstarter

John from JR Magnetics has written in and wanted to share his Kickstarter for a US$50 ultra wide band antenna that he has designed. The size is a just little bit bigger than two credit cards and the advertised coverage is from 750 MHz up to 6 GHz with a VSWR of less than 2.0.

John's Kickstarter text reads below:

Flat Ultra Wide Band Antenna Suitable for SDR

About

I was never satisfied with the commercially available wide band antennas.  They were all too large or did not have suitable VSWR over the frequency range generally required by SDRs.  I read many research papers and ultimately made a omni-directional ultra wide band antenna, but it was too expensive for most people.  Details regarding that antenna can be found at https://www.rtl-sdr.com/constructing-a-3d-printed-wideband-900-mhz-to-11-ghz-antenna/

However,  a bi-directional antenna was good enough for most people, so I have made a flat one.  The antenna I ended up with is 5 inches by 4 inches and about 3 mm thick with an SMA connector.  It is quite definitely not a square patch antenna, which usually has a narrow bandwidth.

This antenna has a VSWR measured to be under 2.00 from around 750 MHz to over 3 GHz.  It simulates to have a VSWR under 2.00 out to over 6 Ghz.  This is enough for most of the available SDRs.  It works very well with WiFi, Bluetooth, Zigbee and other systems within the bandwidth.

Typical Directional Log Antenna

Existing Antennas

The log antenna, Figure 2, has a wide bandwidth, but it is specified as having ranges, because the VSWR rises over 2.00 several times over that range.  The antenna measure sover 40 centimeters long, which is problem for me in a laboratory setting.  It is too large to fit anywhere and wants to be permanently fixed to a pole or something like that.

The other antenna I have is a discone type device, Figure 3.  It is huge.  There is not practical for it to fit on a lab bench around various RF devices.  It is measures around 28 centimeters at its base.  It needs to be elevated above any ground planes, which complicates a laboratory environment with metal bench tops.  I have it sitting on a shelf above the computer monitors on the opposite side of the room away from the lab bench.  This does not work well when I am trying to deal with wireless devices connected to USB hubs on the bench with short range features.

Discone Type Wide Band Antenna

Figure 4 shows the Flat Antenna next to the Log Antenna for a size comparison that illustrates just how much space saving there is with this new device.  This is no small feat.  This Flat Antenna is useful around all manner of RF devices on the bench without causing space issues, getting in the way of instruments and couples well with all of the wireless devices I am using.  It is small enough with a convenient shape for moving it around and keeping it above a metal bench top.  It only needs to be a few centimeters above any ground planes when perpendicular, not horizonal.

Due to its size and shape, near field problems have not been a problem, as with the other antennas.  The antenna is quite directional, which is not much of a problem, since the RF bounces around all over the place.  A Faraday shield is the only way to keep this device from picking out everything in the vicinity.  The neighbors IoT devices create mountains of RF clutter.  This antenna picks up all of it.  If you only want restricted bandwidths, band pass and reject filters can be used.  The load impedance is 50 Ohms across the band making an excellent match for all of the filters I have here.

Our Flat Antenna Size Comparison with the Log Antenna

Specifications

Figure 5 shows the VSWR as measured by the NanoVNA Version 2.  It only goes out to 3 Ghz.  The device must be calibrated before use, or you will get extraneous results.  I am told the VSWR never goes above 2.00 until after 6 GHz.  This is a remarkable antenna.  I never found anything comparable to it on the Internet.

It can be used for all wireless and SDR applications normally within the 750 MHz to 6 GHz bandwidth.  This is not guess work or speculation.  The network analyzer shows the response clearly.

The antenna is 5 inches long by 4 inches wide by roughly 3 mm thick, not counting the SMA connector.

VSWR of Our Flat Antenna

What You Get

You get one (1) antenna, as shown in Figure 1, for each US$50.  You cannot do this yourself for that price.  Your time alone is worth more than that after you do the calculations, simulations and prototyping.  You also would have to deal with fab shops to get this done correctly, which is not always convenient for many people.

In other words, this is a remarkable Ultra Wide Band Antenna at a remarkable price.

Engineering

This has already been done.  I have a Masters Degree in RF Engineering.  I also have all of the simulation tools that are not available to most people, with the exception of some university students.

Manufacturing

I have sources that I use all the time.  I just put this one into the queue.  We also have a minimum order, which is why we Crowd Fund this operation.

Timeline

Once in the queue, it takes about two (2) weeks.  After that, we are only concerned with delivery time.  We intend to use ordinaty Postal Service mail, to keep the cost down, so time of delivery may vary depending upon the destination.

Risks and challenges

We already have laboratory results, so there is nothing to risk in performance. The only other thing that could be troublesome is the lead time by the vendor that manufactures the main component or any delays caused by the Postal Service.

Frugal Radio: SDR Guide Ep 4 – Antenna Basics for SDR Beginners

In this episode of Frugal Radio's series of SDR beginners guide videos he discusses some antenna basics. He shows the most common types of antennas, provides several tips to help improve reception, and shows how to properly tune antennas using online calculators.

Near the end of the video he shows our multipurpose dipole antenna kit and shows how to adjust the telescopic elements for best reception. He demonstrates that simply extending the elements to the maximum length does not result in the best tuning, rather you need to tune the element length for the frequency being received to get the best results.

2020 SDR Guide Ep 4 : Antenna Basics for SDR Beginners inc RTL-SDR / Nooelec NESDR SMArt bundle

Tech Minds: Review of the MLA-30 Active HF Loop Antenna

Over on YouTube Tech Minds has uploaded a new video where he reviews the MLA-30 active HF loop antenna. In the past we have posted about the MLA-30 antenna a several times on the blog as it is the cheapest active loop antenna available on the market, can be powered by the RTL-SDR Blog V3's bias tee, and generally loop antennas can give good HF performance in a small package. In the video he compares the MLA-30 against an end-fed halfwave antenna and concludes that the MLA-30 works well at the lower frequencies, but not so well in the higher bands.

MLA-30 Active HF Loop Antenna

The SWLing Post Reviews the YouLoop Passive Loop Antenna

Over on the SWLing (Short Wave Listening) Post blog Thomas has just uploaded his review of the YouLoop in a post titled "The Airspy Youloop is a freaking brilliant passive loop antenna". If you weren't aware, we are currently selling this loop in our store for US$34.95 incl. free worldwide shipping to most countries. Sales are currently in pre-order as our first batch of units ordered sold out within a day, but we're soon going to receive the second batch in the next few days. 

Thomas is a seasoned shortwave listener who has used many antennas, and in the review he notes that he is extremely impressed with the performance. In his review he tests the antenna in a location that is swimming with RFI and places the loop in the middle of a bedroom. Although the situation is not ideal, Thomas was surprised at the number of signals he was able to receive.

To work properly the YouLoop requires a low noise figure radio like the recommended Airspy HF+ discovery, but Thomas notes that he's also had excellent success with the SDRplay RSPdx running in HDR mode.

YouLoop Portable Passive Magnetic Loop Antenna for HF and VHF
YouLoop Portable Passive Magnetic Loop Antenna for HF and VHF

YouLoop Batch 2 Available for Pre-Order: Estimated Shipping in One Week

A few days ago we posted about our release of the first batch of YouLoop passive HF/VHF loop antenna kits. We underestimated the demand and sold out of kits in less than a day! We now have a second batch currently being manufactured and it should be ready to ship out in about a week from now (late March/early April).

You can currently pre-order this item from our store, and we will ship it out as soon as the stock hits the shelves on our warehouse. For this product we are focusing on non-US customers and US customers can purchase locally from airspy.us. Though we will still fulfill US orders if you want to order from us instead.

If you are interested in further information, search YouLoop on Twitter to see a bunch of new tweets about people talking about and demonstrating this antenna design.

YouLoop Portable Passive Magnetic Loop Antenna for HF and VHF
YouLoop Portable Passive Magnetic Loop Antenna for HF and VHF

Techminds Reviews a HF RX SWL Antenna for Small Spaces and Apartments

Over on his YouTube channel TechMinds has uploaded a video reviewing the X1-HF 1 - 50 MHz Trapped Coil Receiving antenna from Moonraker.eu which goes for £69.95. This is a small electrically short antenna for HF reception which is easy to setup and install, requiring no radials. However, like all short HF antennas it is a compromise.

In the review he uses an SDRplay RSP2 SDR to test HF reception with the antenna. Later in the video he also tests it outside the advertised 1 - 50 MHz range. He concludes that the antenna works very well for it's small size.

HF RX SWL Antenna For Small Spaces And Apartments RTL SDR

New Product in Store: RTL-SDR Blog Magnetic Whip Antenna Set (Great for KerberosSDR Direction Finding)

We've recently released a new Magnetic Whip Antenna Set in our store. The set consists of a heavy duty magnetic mount antenna base with 2M RG59, a 9.5cm fixed whip antenna (usable from 400 MHz to 2 GHz+), and a 17cm to 1m telescopic whip (usable from 100 MHz - 400 MHz).

Click Here to Visit our Store

The antenna set costs US$14.95 each with free shipping. And if you buy four sets you will receive a 15% discount. Currently available to ship worldwide right now from our warehouse in China, and they will be on Amazon in 2-3 weeks.

One application of our KerberosSDR 4-Tuner Coherent RTL-SDR is radio direction finding. This requires four quality omni-directional antennas. We were disappointed to find that there were no high quality magnetic whip antennas available on the market for a low price that we could use with KerberosSDR so we made our own.

The magnetic base is designed carefully with conductive metal that is properly connected to the shield of the coax cable. Most cheap antenna bases just leave the shield connection floating and this causes insufficient coupling to the underlying ground plane resulting in poor performance and poor results when it comes to direction finding and reception.

We've tested this set with KerberosSDR and it is known to work well. The antenna can also of course be used for any other receiving purpose if you prefer to use a whip antenna over our multipurpose dipole antenna set.

In the first two images in the image slider below you can see a comparison between a black base that is not properly bonded to the coax shield, vs the RTL-SDR Blog silver base which is correctly bonded to the coax shield. Both tests used the 9.5cm whip antenna. You can see that the RTL-SDR Blog silver base provides a much lower noise floor and higher signal SNR due to the better ground plane. Also we note that when placing the antenna bases on a metallic surface to create a larger ground plane, the black base showed no further improvement, whereas the RTL-SDR Blog silver base did.

The final three images in the slider show the SWR plots of the two whips on the base. We can see that the 9.5cm whip provides an SWR of less than six below 412 MHz. The telescopic whip can be adjusted to provide better SWR for lower frequencies.

RTL-SDR Blog Antenna Base (Coax shield properly connected to base)
Generic Black Antenna Base (Coax shield not connected to base)
9.5cm Whip SWR Plot
Telescopic Whip Collapsed SWR Plot
Telescopic Whip Fully Expanded SWR Plot
RTL-SDR Blog Antenna Base (Coax shield properly connected to base) Generic Black Antenna Base (Coax shield not connected to base) 9.5cm Whip SWR Plot Telescopic Whip Collapsed SWR Plot Telescopic Whip Fully Expanded SWR Plot

JR Magnetics Small Ultra Wide Band 750 MHz to 6 GHz Antenna for SDRs on Kickstarter

John from JR Magnetics has written in and wanted to share his Kickstarter for a US$50 ultra wide band antenna that he has designed. The size is a just little bit bigger than two credit cards and the advertised coverage is from 750 MHz up to 6 GHz with a VSWR of less than 2.0.

John's Kickstarter text reads below:

Flat Ultra Wide Band Antenna Suitable for SDR

About

I was never satisfied with the commercially available wide band antennas.  They were all too large or did not have suitable VSWR over the frequency range generally required by SDRs.  I read many research papers and ultimately made a omni-directional ultra wide band antenna, but it was too expensive for most people.  Details regarding that antenna can be found at https://www.rtl-sdr.com/constructing-a-3d-printed-wideband-900-mhz-to-11-ghz-antenna/

However,  a bi-directional antenna was good enough for most people, so I have made a flat one.  The antenna I ended up with is 5 inches by 4 inches and about 3 mm thick with an SMA connector.  It is quite definitely not a square patch antenna, which usually has a narrow bandwidth.

This antenna has a VSWR measured to be under 2.00 from around 750 MHz to over 3 GHz.  It simulates to have a VSWR under 2.00 out to over 6 Ghz.  This is enough for most of the available SDRs.  It works very well with WiFi, Bluetooth, Zigbee and other systems within the bandwidth.

Typical Directional Log Antenna

Existing Antennas

The log antenna, Figure 2, has a wide bandwidth, but it is specified as having ranges, because the VSWR rises over 2.00 several times over that range.  The antenna measure sover 40 centimeters long, which is problem for me in a laboratory setting.  It is too large to fit anywhere and wants to be permanently fixed to a pole or something like that.

The other antenna I have is a discone type device, Figure 3.  It is huge.  There is not practical for it to fit on a lab bench around various RF devices.  It is measures around 28 centimeters at its base.  It needs to be elevated above any ground planes, which complicates a laboratory environment with metal bench tops.  I have it sitting on a shelf above the computer monitors on the opposite side of the room away from the lab bench.  This does not work well when I am trying to deal with wireless devices connected to USB hubs on the bench with short range features.

Discone Type Wide Band Antenna

Figure 4 shows the Flat Antenna next to the Log Antenna for a size comparison that illustrates just how much space saving there is with this new device.  This is no small feat.  This Flat Antenna is useful around all manner of RF devices on the bench without causing space issues, getting in the way of instruments and couples well with all of the wireless devices I am using.  It is small enough with a convenient shape for moving it around and keeping it above a metal bench top.  It only needs to be a few centimeters above any ground planes when perpendicular, not horizonal.

Due to its size and shape, near field problems have not been a problem, as with the other antennas.  The antenna is quite directional, which is not much of a problem, since the RF bounces around all over the place.  A Faraday shield is the only way to keep this device from picking out everything in the vicinity.  The neighbors IoT devices create mountains of RF clutter.  This antenna picks up all of it.  If you only want restricted bandwidths, band pass and reject filters can be used.  The load impedance is 50 Ohms across the band making an excellent match for all of the filters I have here.

Our Flat Antenna Size Comparison with the Log Antenna

Specifications

Figure 5 shows the VSWR as measured by the NanoVNA Version 2.  It only goes out to 3 Ghz.  The device must be calibrated before use, or you will get extraneous results.  I am told the VSWR never goes above 2.00 until after 6 GHz.  This is a remarkable antenna.  I never found anything comparable to it on the Internet.

It can be used for all wireless and SDR applications normally within the 750 MHz to 6 GHz bandwidth.  This is not guess work or speculation.  The network analyzer shows the response clearly.

The antenna is 5 inches long by 4 inches wide by roughly 3 mm thick, not counting the SMA connector.

VSWR of Our Flat Antenna

What You Get

You get one (1) antenna, as shown in Figure 1, for each US$50.  You cannot do this yourself for that price.  Your time alone is worth more than that after you do the calculations, simulations and prototyping.  You also would have to deal with fab shops to get this done correctly, which is not always convenient for many people.

In other words, this is a remarkable Ultra Wide Band Antenna at a remarkable price.

Engineering

This has already been done.  I have a Masters Degree in RF Engineering.  I also have all of the simulation tools that are not available to most people, with the exception of some university students.

Manufacturing

I have sources that I use all the time.  I just put this one into the queue.  We also have a minimum order, which is why we Crowd Fund this operation.

Timeline

Once in the queue, it takes about two (2) weeks.  After that, we are only concerned with delivery time.  We intend to use ordinaty Postal Service mail, to keep the cost down, so time of delivery may vary depending upon the destination.

Risks and challenges

We already have laboratory results, so there is nothing to risk in performance. The only other thing that could be troublesome is the lead time by the vendor that manufactures the main component or any delays caused by the Postal Service.

Frugal Radio: SDR Guide Ep 4 – Antenna Basics for SDR Beginners

In this episode of Frugal Radio's series of SDR beginners guide videos he discusses some antenna basics. He shows the most common types of antennas, provides several tips to help improve reception, and shows how to properly tune antennas using online calculators.

Near the end of the video he shows our multipurpose dipole antenna kit and shows how to adjust the telescopic elements for best reception. He demonstrates that simply extending the elements to the maximum length does not result in the best tuning, rather you need to tune the element length for the frequency being received to get the best results.

2020 SDR Guide Ep 4 : Antenna Basics for SDR Beginners inc RTL-SDR / Nooelec NESDR SMArt bundle

Tech Minds: Review of the MLA-30 Active HF Loop Antenna

Over on YouTube Tech Minds has uploaded a new video where he reviews the MLA-30 active HF loop antenna. In the past we have posted about the MLA-30 antenna a several times on the blog as it is the cheapest active loop antenna available on the market, can be powered by the RTL-SDR Blog V3's bias tee, and generally loop antennas can give good HF performance in a small package. In the video he compares the MLA-30 against an end-fed halfwave antenna and concludes that the MLA-30 works well at the lower frequencies, but not so well in the higher bands.

MLA-30 Active HF Loop Antenna

The SWLing Post Reviews the YouLoop Passive Loop Antenna

Over on the SWLing (Short Wave Listening) Post blog Thomas has just uploaded his review of the YouLoop in a post titled "The Airspy Youloop is a freaking brilliant passive loop antenna". If you weren't aware, we are currently selling this loop in our store for US$34.95 incl. free worldwide shipping to most countries. Sales are currently in pre-order as our first batch of units ordered sold out within a day, but we're soon going to receive the second batch in the next few days. 

Thomas is a seasoned shortwave listener who has used many antennas, and in the review he notes that he is extremely impressed with the performance. In his review he tests the antenna in a location that is swimming with RFI and places the loop in the middle of a bedroom. Although the situation is not ideal, Thomas was surprised at the number of signals he was able to receive.

To work properly the YouLoop requires a low noise figure radio like the recommended Airspy HF+ discovery, but Thomas notes that he's also had excellent success with the SDRplay RSPdx running in HDR mode.

YouLoop Portable Passive Magnetic Loop Antenna for HF and VHF
YouLoop Portable Passive Magnetic Loop Antenna for HF and VHF

YouLoop Batch 2 Available for Pre-Order: Estimated Shipping in One Week

A few days ago we posted about our release of the first batch of YouLoop passive HF/VHF loop antenna kits. We underestimated the demand and sold out of kits in less than a day! We now have a second batch currently being manufactured and it should be ready to ship out in about a week from now (late March/early April).

You can currently pre-order this item from our store, and we will ship it out as soon as the stock hits the shelves on our warehouse. For this product we are focusing on non-US customers and US customers can purchase locally from airspy.us. Though we will still fulfill US orders if you want to order from us instead.

If you are interested in further information, search YouLoop on Twitter to see a bunch of new tweets about people talking about and demonstrating this antenna design.

YouLoop Portable Passive Magnetic Loop Antenna for HF and VHF
YouLoop Portable Passive Magnetic Loop Antenna for HF and VHF

Techminds Reviews a HF RX SWL Antenna for Small Spaces and Apartments

Over on his YouTube channel TechMinds has uploaded a video reviewing the X1-HF 1 - 50 MHz Trapped Coil Receiving antenna from Moonraker.eu which goes for £69.95. This is a small electrically short antenna for HF reception which is easy to setup and install, requiring no radials. However, like all short HF antennas it is a compromise.

In the review he uses an SDRplay RSP2 SDR to test HF reception with the antenna. Later in the video he also tests it outside the advertised 1 - 50 MHz range. He concludes that the antenna works very well for it's small size.

HF RX SWL Antenna For Small Spaces And Apartments RTL SDR

New Product in Store: RTL-SDR Blog Magnetic Whip Antenna Set (Great for KerberosSDR Direction Finding)

We've recently released a new Magnetic Whip Antenna Set in our store. The set consists of a heavy duty magnetic mount antenna base with 2M RG59, a 9.5cm fixed whip antenna (usable from 400 MHz to 2 GHz+), and a 17cm to 1m telescopic whip (usable from 100 MHz - 400 MHz).

Click Here to Visit our Store

The antenna set costs US$14.95 each with free shipping. And if you buy four sets you will receive a 15% discount. Currently available to ship worldwide right now from our warehouse in China, and they will be on Amazon in 2-3 weeks.

One application of our KerberosSDR 4-Tuner Coherent RTL-SDR is radio direction finding. This requires four quality omni-directional antennas. We were disappointed to find that there were no high quality magnetic whip antennas available on the market for a low price that we could use with KerberosSDR so we made our own.

The magnetic base is designed carefully with conductive metal that is properly connected to the shield of the coax cable. Most cheap antenna bases just leave the shield connection floating and this causes insufficient coupling to the underlying ground plane resulting in poor performance and poor results when it comes to direction finding and reception.

We've tested this set with KerberosSDR and it is known to work well. The antenna can also of course be used for any other receiving purpose if you prefer to use a whip antenna over our multipurpose dipole antenna set.

In the first two images in the image slider below you can see a comparison between a black base that is not properly bonded to the coax shield, vs the RTL-SDR Blog silver base which is correctly bonded to the coax shield. Both tests used the 9.5cm whip antenna. You can see that the RTL-SDR Blog silver base provides a much lower noise floor and higher signal SNR due to the better ground plane. Also we note that when placing the antenna bases on a metallic surface to create a larger ground plane, the black base showed no further improvement, whereas the RTL-SDR Blog silver base did.

The final three images in the slider show the SWR plots of the two whips on the base. We can see that the 9.5cm whip provides an SWR of less than six below 412 MHz. The telescopic whip can be adjusted to provide better SWR for lower frequencies.

RTL-SDR Blog Antenna Base (Coax shield properly connected to base)
Generic Black Antenna Base (Coax shield not connected to base)
9.5cm Whip SWR Plot
Telescopic Whip Collapsed SWR Plot
Telescopic Whip Fully Expanded SWR Plot
RTL-SDR Blog Antenna Base (Coax shield properly connected to base) Generic Black Antenna Base (Coax shield not connected to base) 9.5cm Whip SWR Plot Telescopic Whip Collapsed SWR Plot Telescopic Whip Fully Expanded SWR Plot

Building a DIY 2.4 GHz Helical Feed for the QO-100/Es’Hail-2 Satellite

Over on his YouTube channel Adam 9A4QV has uploaded a short video that demonstrates his 2.4 GHz homemade helical feed designed to be used with a reflector (prime feed satellite dish) for QO-100/Es'Hail-2 satellite reception. The antenna is made from an old can, 2-turns of copper wire, and a plastic insulator to hold the turns in place. The two turns are wound in left hand circular polarization (LHCP), because when used with a satellite dish reflector it will result in right hand circular polarization (RHCP), which is the polarization QO-100 uses.

One of the most important parts of the video is when Adam shows how he matches the antenna to 50 Ohms. He notes that without matching the antenna won't work properly, and the return loss will be about 8 dB or even less, resulting in poor performance. With matching he obtains 30 dB return loss.

Helical feed for the 2.4 GHz QO-100 satellite