Tagged: iridium

Nils Reviews our RTL-SDR Blog L-Band Active Patch Antenna

Over on his blog Nils Schiffhauer (DK8OK) has recently uploaded a review of our RTL-SDR Blog Active L-Band Patch Antenna. This is a satellite patch antenna designed for experimenters who want to receive Inmarsat, Iridium, GPS and other GNSS signals. It covers 1525 - 1660 MHz. (Please note it does not cover GOES or other L-band weather satellites as these are much weaker signals that require a dish). The antenna comes as a set with mounting hardware and extension cable and can be purchased on our store for $49.95 including free worldwide shipping to most countries.

In his review Nils tests the patch antenna with his wideband BladeRF software defined radio showing a wide 60 MHz of bandwidth being received. He then goes on to show it being used to receive AERO, via the JAERO decoder, and STD-C via the Tekmanoid decoder.

We want to take this opportunity to pre-announce that due to rising shipping costs the price of this antenna set will be going up by $10 in early 2022. Before the price raise we will put out another post, but if you are interested in one we'd recommend picking one up soon.

Nils tests the water resistance of the antenna.

SignalsEverywhere tests our RTL-SDR Blog Active L-Band Patch Antenna

Sarah from the SignalsEverywhere YouTube channel is back this week with a video review and demonstration of our RTL-SDR Blog Active L-Band patch antenna, which is designed for receiving Inmarsat and Iridium satellites between 1525 - 1660 MHz with an RTL-SDR or other bias tee capable SDR.

In the video Sarah demonstrates the patch antenna in action running in SDR++, discusses some of the features and compares it against another patch antenna. She goes on to briefly show JAERO receiving and decoding an 8400bps AERO voice channel.

If you're interested, this antenna has also been reviewed by Frugal Radio, Tech Minds, and Mike from SDRplay

The patch is currently in stock in our store for $49.95 shipped worldwide, or on Amazon USA for US customers. We note that previous problems (as explained in our earlier post) with cracks in the plastic in the latest batch with grey enclosures have been resolved now, and units shipping now are without defect.

What can you do with this antenna?

The Best L Band Antenna for The Money PERIOD

RTL-SDR Blog Active L-Band Patch Antenna for Inmarsat, Iridium, GPS Back in Stock

Just a quick note to say that the second batch of our Active L-Band Patch Antenna for receiving Inmarsat, Iridium and other L-Band satellites is now in stock, available to be shipped from our warehouse in China from early next week. Amazon will be stocked within the next 1-2 months as the freighter will take time to arrive.

Please see our store for ordering details.

Apologies as we've had to temporarily suspend sales of this product as a manufacturing defect has been discovered in this batch. The defect is that on a number of units the plastic around the screws is cracking, and this was caused by a factory worker over torqueing a pneumatic screwdriver.

The antenna itself will work fine, and it probably won't even affect weather tightness, but it is certainly a defect. If your unit already shipped out and your unit has these cracks, please let us know at [email protected] and we will get the factory to ship you a replacement enclosure. For unshipped units we will be issuing a refund within the next few days.

Update: The units have been repaired and are available for shipping again.

Pricing remains the same at US$49.95 including free worldwide shipping to most countries. A reminder to EU customers: please order from our Aliexpress or eBay stores as due to the new IOSS laws we need to now use those marketplaces to collect and remit VAT upon your purchase, instead of upon import at the border.

This second batch comes in a gray color as feedback from the previous batch indicated that a lighter color is preferred to avoid excess heating from the sun.

If you are hearing about this patch antenna for the first time, please see our original release post for more information. In short this is an amplified patch antenna designed to be used with bias tee capable SDRs that can provide 3.3V - 5V power, such as our RTL-SDR Blog V3 dongle, Airspy, SDRplay or HackRF.

The antenna allows for reception of L-band satellites that transmit between 1525 - 1660 MHz, such as Inmarsat, Iridium and GPS. Please note it is *not* for receiving weaker signals like HRPT and GOES which require a dish antenna.

The patch comes with useful mounting accessories including a window suction cup, bendable tripod and 3M RG174 coax cable. The patch and active circuitry is enclosed in a weather proof enclosure.

What can you do with this antenna?

Two reviews of our new L-Band Patch Antenna + Stock Update

Last month we released our new L-band active patch antenna for sale, and not too long after we had a review from Frugal Radio praising it. We now have two more YouTube reviews available to share.

The first is from Tech Minds who does a teardown and demonstrates it receiving and decoding the Inmarsat STD-C NCS channel, receiving and decoding GPS and receiving Iridium signals. The second is from Mike Ladd from SDRplay, who tests it with an SDRplay RSP1A software defined radio. He shows that the patch works perfectly with an RSP1A, and demonstrates it receiving and decoding STD-C while mounted on the dash of his vehicle.

L-Band Patch Stock Availability Note: We note that we are already close to selling out of the first batch of these units as they sold much faster than expected! New sales of this patch are currently backordered but we expect to have a few more units from this first batch available by the end of next week. Also the freighter with Amazon USA stock should be arriving any day now, but it could still take a few weeks to get through the port and reach the warehouse due to the current port delays.

The second production batch of this antenna might still be a while away due to the electronic component shortage crisis occurring now, so if you were thinking about picking one up, please order ASAP.

RTL-SDR BLOG L-BAND Patch Antenna Version 2 - Inmarsat - Iridium - GPS

SDRplay RSP1a - RTL SDR Blog L-Band Patch antenna

Preorder Sale: Active L-Band 1525-1660 Inmarsat and Iridium Patch Back In Stock for $44.95

We have just received stock of our new L-band active patch antenna design. The antenna is designed for receiving L-band satellites such as Inmarsat, Iridium, GPS and other satellites that transmit between 1525 - 1660 MHz (please note that you cannot use it for weak signals that require a dish like HRPT or GOES). The antenna comes as a set with a large suction cup, 3M RG174 extension cable and bendable tripod to help with mounting. Preorder pricing is US$44.95 including free worldwide shipping to most countries shipped from our warehouse in Shanghai. At the end of this week (extended for one more week!) pricing will rise to the standard cost of US$49.95. Amazon stock will require time, and won't be in for at least 6+ weeks.

Please see our store to order the unit

Like our previous patch design, this is an actively amplified antenna as it contains a built in low noise amplifier which takes power from a 3.3 - 5V bias tee. This power is available from from our RTL-SDR Blog V3 dongles, and other SDRs like the Airspy, HackRF and SDRplay. It also has a built in SAW filter after the LNA to help reduce terrestrial interference.

Compared to the previous design the new patch is larger (175 x 175 mm) with higher gain and wider radiation pattern. This allows for much easier pointing of the antenna and for much stronger signals. The upper frequency range has also been extended to 1660 MHz from 1625 MHz. The included suction cup is also much larger allowing for the patch to point at more angles without being restricted by the window. The patch is enclosed within a new weatherproof plastic enclosure. 

L-Band Patch with Accessories
L-Band Patch Mounting Examples

The screenshots below show the patch receiving various signals like AERO, STD-C and Iridium

Inmarsat Reception
Inmarsat Reception
Airspy Showing Patch Bandwidth
GPS "hump" visible

Usage Tips

  • The antenna should be used with one meter or more of coax cable. It may perform poorly if the RTL-SDR is placed right at the antenna due to interference. If you want to run very long cable, then low loss coax should be used. 
  • The patch can be used flat, or angled towards the satellite. Angling it towards the satellite will yield significantly higher gain.
  • If you have very strong cell phone interference in your area, try using the patch a bit lower to the ground, and use buildings to block the interfering signal.
  • If you want to mount this on a car roof, you can use a standard mag-mount camera adapter.
  • When using the suction cup, ensure you wipe down the cup and the window surface before sticking it on. Have a backup plan in case the suction fails.

What can you do with this antenna?

DragonOS: Decoding Iridium Satellites with the Iridium Toolkit and an RTL-SDR

DragonOS is a ready to use Linux OS image that includes various SDR programs preinstalled and ready to use. The creator Aaron also runs a YouTube channel that has multiple tutorial videos demonstrating software built into DragonOS.

In his latest video Aaron explores Iridium reception with an RTL-SDR Blog V3, RTL-SDR Blog Active L-Band Patch Antenna and Iridium Toolkit/gr-iridium. Iridium is a satellite constellation that provides services such as global paging, satellite phones, tracking and fleet management services, as well as services for emergency, aircraft, maritime and covert operations too.

In the video he shows how to edit the config file to turn the bias tee on, how to record Iridium data, how to install the AMBE voice decoder, and finally how to decode the Iridum data with Iridium toolkit and play voice recordings.

DragonOS LTS Decoding Iridium satellites with the Iridium toolkit (gr-iridium, RTL-SDR)

Increasing L-Band Active Patch SNR by using it as a Feed for a Satellite Dish

Recently RTL-SDR.COM reader Bert has been experimenting with our active L-band patch antenna product. He's written in to share that he's found that using it as a feed for a satellite dish works well to improve SNR on those weaker 10500 AERO signals which Bert found that he could not decode from his location due to insufficient SNR. Our active L-band patch antenna receives signals from 1525 - 1637 MHz and can be used for signals from Inmarsat, Iridium and GPS satellites.

To use the patch as a feed Bert used a 40mm drain pipe and mounted the antenna on the end of the pipe. The drain pipe fits perfectly into the LNB holder, and once mounted the distance and polarization rotation can easily be adjusted for best SNR. He also found that adding a secondary sub-reflector about 17x17cm in size helped to boost SNR by about 3-5 dB too.

Build steps to use the Active L-band Patch with a Satellite Dish
Build steps to use the Active L-band Patch with a Satellite Dish

Bert has tested the active L-band patch as a feed on a 65cm satellite dish and a smaller 40cm dish, both with good results.

SNR Results
SNR Results

Tech Minds Demonstrates Iridium Live on a Raspberry Pi

Over on YouTube Tech Minds has uploaded a video of him demonstrating Iridium Live plotting Iridium satellite tracks in real time. We just posted about Iridium Live yesterday. It is a new program by microp11, who is also the author of Scytale-C, a useful Inmarsat STD-C decoder. The software works with gr-iridium to visualize Iridium satellite tracks as they pass overhead.

In the video Tech Minds runs the software on a Raspberry Pi with an Airspy. The current video is only a demonstration, but in the near future he promises to upload a full tutorial

IridiumLIVE - Real Time Visualization Of Iridium Satellites - Raspberry Pi