Tagged: dipole

Upgrading the Coax on a TV Dipole Antenna for Improved Reception

Over on his YouTube channel Corrosive has uploaded a useful video showing how to modify a standard TV dipole to make it better for general radio use. Many TV dipoles come standard with twin lead, or very poor quality coax cable. Corrosive shows in his video how simple it is to modify and improve one of these by adding high quality coax with a BNC connector.

These TV dipoles are great as general purpose antennas, and are especially useful for making V-dipole antennas for NOAA/Meteor M2 reception.

Using a TV Dipole Antenna for NOAA Satellite Reception

Over on YouTube icholakov has uploaded a video showing how effective a simple old TV bunny ears antenna can be at receiving NOAA satellite images. The old TV antenna is telescoping so it can be adjusted to be resonant for many frequencies, and for NOAA satellites about 20 inches makes it resonant. Using the antenna as a V-Dipole and placing it in a North to South direction optimizes the radiation pattern towards the sky, allowing for good reception of the NOAA satellite. Using it this way also helps to null out strong vertically polarized stations. More information on the V-Dipole can be found on our previous post where we posted about Adam 9A4QV’s idea to use the V-Dipole for satellite reception.

Also related to this post is a sneak preview on our new product: We’ve also caught onto the idea that TV antenna dipoles are extremely versatile, and are in the final stages of releasing a simple telescopic dipole product similar to the TV antenna used in this video. It will be released as an antenna set that comes with some portable mounting solutions like a suction cup and bendy tripod, and 3M of RG174 coax so that the antenna can be used anywhere. Target price is $10 -15 USD incl. shipping from China. This will probably also replace the stock telescopic whip antenna currently used in our dongle sets since the telescopic dipole is simply much more versatile.

ISS Packet Repeater Received with RTL-SDR

YouTube user ronpaulatemybaby has posted a video showing his reception of the International Space Station (ISS) amateur packet repeater on 145.825 MHz, using the rtl-sdr. He used a R820T dongle, two meter dipole, SDRSharp and decoding software MixW.

RTL-SDR Tutorial: Cheap ADS-B Aircraft RADAR

The RTL-SDR can be used as a super cheap real time air radar. Modern planes use something called an ADS-B (Automatic Dependent Surveillance-Broadcast) Mode-S transponder, which periodically broadcasts location and altitude information to air traffic controllers. The RTL-SDR can be used to listen to these ADS-B signals, which can then be used to create your very own home aircraft radar system. Compared to dedicated commercial ADS-B receivers which can go for between $200 – $1000, the $20 RTL-SDR is very attractive for the hobbyist in terms of price. However, note that the RTL-SDR probably shouldn’t be used for ADS-B navigation in a real aircraft for safety reasons. 

ADS-B broadcasts at a frequency of 1090 MHz. It has been discovered by the RTL-SDR community, that the RTL-SDR with R820T tuner has the best sensitivity at this frequency. The E4000 and other tuners perform poorly in comparison. So it is recommended that you obtain an R820T tuner if you want to set up ADS-B decoding with the RTL-SDR. Recently there has also been talk about the R820T2 tuner, which seems to have slightly better performance too. See the Buy RTL-SDR dongles page for more information on where to purchase.

We also now note that recently new higher end SDR’s like the $199 Airspy have developed very good ADS-B receivers that are several times more sensitive that the RTL-SDR.

Examples of RTL-SDR used as an ADS-B air radar

In this video, YouTube user Superphish shows a timelapse of air traffic over New Zealand using RTL-SDR, ADSB# and Virtual Radar Server.

Continue reading