wideband antenna for satellite reception

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wergor
Posts: 3
Joined: Tue Aug 23, 2016 7:34 am

wideband antenna for satellite reception

Post by wergor » Tue Aug 23, 2016 1:23 pm

Hi,

I bought a rtl-sdr.com v3 dongle last week that I would like to use for satellite reception. I'm not interested in any specific satellite but want to receive satellites throughout the dongle's frequency range - from NOAA/Meteor and Funcube to Inmarsat and Iridium, preferably with a single antenna. The antenna would be attached to a motorized mount to track satellites moving across the sky, so a high directionality is desired.
Is this feasible, and if yes, can you point me in the general direction of a suitable antenna? I was thinking a (dual polarized) log-per antenna and one or more lna4all LNAs, but it's hard to find a log-per antenna that covers this frequency range.

rtlsdrblog
Site Admin
Posts: 2190
Joined: Mon Nov 19, 2012 11:54 pm

Re: wideband antenna for satellite reception

Post by rtlsdrblog » Wed Aug 24, 2016 12:22 am

It might be hard or impossible to find an antenna that covers such a wide frequency range with a decent level of gain. Plus it would likely be huge if it had to reach down to 137 MHz. In addition you'd probably want filtering on such a wideband antenna as well, meaning you'd need to build some sort of circuit to switch the filtering in and out. It's probably best to buy or build one antenna for 137 MHz, and one for Inmarsat and mount them together. You don't really need a directional antenna for NOAA. A simple QFH should suffice. For Funcube a Yagi might be needed. Inmarsat is geosyncrhonous, so you won't need a movable antenna for that either.

But if you really want directionality, a 137MHz crossed Yagi, and a helical for Inmarsat/L-band would be good.

There are some wideband directional vivaldi antenna here, http://rfspace.com/RFSPACE/Antennas.html, but non go down to 137 MHz, and the UWB-5 is huge. https://twitter.com/ibelings/status/699 ... 84/photo/1

Aussie Susan
Posts: 35
Joined: Sun Jul 31, 2016 1:55 am

Re: wideband antenna for satellite reception

Post by Aussie Susan » Wed Aug 24, 2016 3:09 am

Have a look at what the Radio Amateurs use to talk with the satellites. They often use a mixture of 2m and 70cm antenna on a steerable (or hand-held) mount.
137MHz is close to the 2m frequency range so suitable adjustments to the antenna can be made there. You can probably also replace the 70cm antenna with something that will match the other frequencies you are interested in (1690MHz?).
Also as you are only receiving, you can probably get away with lighter construction and/or more antenna on the same mount.
Having said all of that, 'directional' and 'wide bandwidth' generally do nto go together well.
Susan

wergor
Posts: 3
Joined: Tue Aug 23, 2016 7:34 am

Re: wideband antenna for satellite reception

Post by wergor » Thu Aug 25, 2016 6:52 am

thank you both.
I think I'll start with QFH and try some yagis some time in the future. I didn't know about vivaldi antennas, thanks for pointing these out.

Stry
Posts: 12
Joined: Thu Dec 03, 2015 8:18 am

Re: wideband antenna for satellite reception

Post by Stry » Sat Feb 17, 2018 2:41 pm

See Tindie or viewtopic.php?f=6&t=2080 for an inexpensive Vivaldi instead of the venerable RFspace one's.

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