Best Antenna for RTL Dongle


#1

Can anyone suggest the best antenna to use with the RTL dongle? Does using something other than the factory supplied antenna matter that much?


#2

If your dongle comes with a magnetic base whip antenna, I’ve have a lot of luck (~200 nautical miles range) by cutting the radial down to ~66mm and attaching it to a flat metal plate.

If you don’t want to damage the antenna that came with the dongle, a ground plane is pretty simple and will give the same (~200 nautical mile) range.

Here’s one I made (sorry about the terrible quality) out of a BNC socket I had lying around. All the radials are ~66mm long

The copper is from some spare wire I stripped.

I’ve having excellent (up to 300nautical miles) results with a coax collinear antenna. Use 75 Ohm RG6 cable and keep the dongle as close to the antenna as possible for best results.


#3

I don’t know about best, but a simple collinear antenna is pretty easy to make, works well, and cheap to boot.
I made on similar to the one described below with only six segments as a test:
balarad.net/ (found on a quick google search)

I have been dragging it around the country on a summer trip hoisted atop the RV in the evenings. I have regularly gotten signals 200NM+ when viewshed was good. I found the biggest limitation was the adjacent motorhome blocking the sky. When I get home, I will be making another 8 or 12 segment antenna.

The biggest problem I found so far has been finding reliable internet connections. YMMV


#4

I’d be interested to know what you guys use for feed line for a run of around 55 feet.

Thanks, Dan


#5

I’m currently using a 50’ run of RG6 with an adapter on the dongle that I got off Amazon. Got the cable at Lowes so I didn’t have to terminate it myself.


#6

Im using an 8 elem Coaxial that I built and put into a 1" PVC tube and feed with 25ft of good quality RG6. I get out to 200+ miles so far. Im surrounded by mountains (Seattle Area) so I dont expect 400 miles.


#7

At my home location, I have a 7-8ft long coax antenna with about 50-60ft of coax feed to the RTL dongle.


#8

When you say you get 200nm of coverage, is that 200nm from your location to the furthest plane, I.E radius, or 200nm diameter?

What do you use for lightning protection?

thanks, Dan


#9

I’ve been doing a number of tests with Coaxial Collinear (CoCo) antennas.

I started with an 8 element with a 1/4 wave tip and have done the following tests, each lasting around 48 hours.

8 Element + 1/4 wave
8 Element
6 Element
5 Element

So far the 5 element is the best, It picks up out to 240 nautical miles while still picking up from near overhead too. The 8 Element with 1/4 wave tip missed a lot in the 50-100 nautical mile range.

I’ve rendered plots of the first three above as I’m currently testing the 5 element before dropping down one element at a time.

I have a 50cm RG174 “pigtail” between the antenna and a RTL-SDR, so very little cable loss.


#10

Farthest Plane. My Radius is different depending on direction due to trees, tower, hills etc etc.


#11

I’ve made up the simple half wave dipole, with amplifier and put it outside, It’s about 8m above ground level

  • it’s a temporary rig made up of bit’s I had in the hobby room and shed. I will take it down soon.

coax used for the dipole has a segmented polythene tube with 6 segments as air gaps - I’m not sure that a foam dielectric not carry water to the amplifier.

this gives 225nm + in the best direction (270 statute miles, 420km)

range diagram, rings are at 25nm

The rig uses a satellite dish "http://goo.gl/IxfjLk"wrapped in self amalgamating tape, powered up the wire using a simple Voltage Injector

The amplifier is powered off a 12 Netgear Router PSU, the receiver is using the extra Raspberry Pi + Dongle I have for the feeder project

6-Sep-2014 - I’m going to take this test rig down - here is this mornings virtual radar capture - rings are at 25 nautical miles


#12

FWIW, I used the stock ‘cheapie’ SDR rig similar to the one pictured below as I got my rig running. With very poor antenna placement I have a range of about 60 miles or so. Of course, YMMV.


#13

Can you share how you made this diagram? I’m curious to see what mine would look like!


#14

[quote=“drsprite”]

I used virtual radar server running on a PC collecting data from Dump1090 running on the Pi

adjust parameters to suit your situation


make sure the receiver is enabled

then you use a web browser to access virtual radar server 127.0.0.1/VirtualRadar

play with the menu options, in particular the receiver ranges.


#15

Thanks Peter.
I’m new to this and this info really helps me trying the newly built Collinear!
/paul


#16

I’m using both an 8-segment collinear and the dipole (photo below) with my RTL2832u dongles. Have used these antennas simultaneously for several months and it’s a toss-up in terms of performance. I like the dipole because it can travel well. Both are indoors on a windowsill and the dongles are attached close to the antennas with long USB leads to the computers.

Using the existing magnetic base from the stock antenna that came with the dongle, I fashioned the dipole from heavy duty copper-clad steel antenna wire and was able to create a couple of small loops at the bottom that could be force-threaded onto the base. Here are the instructions and dimensions I used:

    [sprut.de/electronic/pic/proj ... sb_en.html](http://www.sprut.de/electronic/pic/projekte/adsb/adsb_en.html)

The horizontal loops on my antenna are all fashioned by hand tools. Worth noting that the connections inside the existing base are not strong and I’ve managed to break the connection and then wonder why the antenna doesn’t work ! The antenna sits atop a small piece of steel acting as the ground plane but it’s a random size probably not optimal.

A caveat – I make no claims about distance nor the relative performance of the two antennas. We live in a narrow valley surrounded by tall hills on three sides. It is entirely possible that one of these would out-perform the other if our line-of-sight were better. I can say that it is far better than the stock antennas. Can receive in the direction where the valley opens out to around 175 nm max.

Richard


#17

You will see a huge increase in range if you open the window and put the antenna outside the glass.

And another if you can raise it above roof level.


#18

mines an 8 element home made vertical picture here

dropbox.com/s/168oo8ktbf2qu … l.jpg?dl=0

seem to get good results, 200+ miles occasionally, but more 50-150mile range

RTL Dongle-Rpi-Piaware-Dump1090

as with any high frequency, a big must is the coax quality