RTL2832U dongle antenna worries

Here you can discuss radio related computer software and computer control of radio equipment.
Post Reply
User avatar
loudassassin
Super Member
Super Member
Posts: 121
Joined: 22 Jan 2012, 19:28
Location: North Staffs

RTL2832U dongle antenna worries

Post by loudassassin » 06 Sep 2018, 22:30

Hiya folks, I've got myself an adapter to use PL259 connectors on my little blue dongle. The choice of antennas to try it with are a home made inverted v-dipole for 11M, or a mag mount with a modulator thingy on it.
The little dongle does get a little bit toasty warm after a while and im worried that by connecting a large antenna i might damage the thing.
The reason i think i might damage it is because for some reason ive got it in my head that a wire can picks up radio waves and if its long enough can generate some voltage or current and a down converter needs to be used?. I dont know if this is true or not, and i wouldnt imagine a cb antenna would damage my dongle,and i dont know what a down converter is or does either?
Just thought id get some opinions to see if its safe to hook up or not?
Cheers
Mark

User avatar
radiogaga
Top Poster
Top Poster
Posts: 1465
Joined: 04 Sep 2010, 20:37
Call Sign: 26TM399

Re: RTL2832U dongle antenna worries

Post by radiogaga » 06 Sep 2018, 23:02

Yes, it’s safe to hook up. I have a variety of dongles and never had a problem with any of them being connected to any antenna. You over course need to be mindful of lightning and front end overload. It doesn’t quite work they Way you have described your worries. (Ish)

The received signal is not going to make the dongle warm (unless you overload the front end) I’ve got (had) around 10 SDR radios of various guises and they all get warm, not hot to the touch. The SDRplay duo seems to be the least effected.

https://www.rtl-sdr.com/rtl-sdr-heat-di ... al-camera/

I use my cheap blue dongle as second ADSB RX, it’s fine there with a filter, rubbish without and around half as effective as the FlightAware Pro. I have found the cheaper dongles a little deaf below 60mhz, compared to the SDRplay.

Don’t know where you are but there is little 11m activity here on commercial gear let alone hunting it on a dongle but good luck...

If it were me i’d go inverted V.

PS****Just one thing, don’t transmitted in close proximity to the RX of the dongle or antenna, that could fry it, and quickly too. (I may have misunderstood your question and that’s what you were asking)

PPS **** maybe worth using a small USB extension to get the dongle in some free space to keep it cool.

PPPS**** you could lower the sample rate to reduce the work th dongle is doing, that would keep it cooler but I really wouldn’t worry

Far more interesting uses for the SDR than 11m
26TM399 Hampshire and Isle of Wight
30TM399 Northern Costa Blanca

User avatar
loudassassin
Super Member
Super Member
Posts: 121
Joined: 22 Jan 2012, 19:28
Location: North Staffs

Re: RTL2832U dongle antenna worries

Post by loudassassin » 06 Sep 2018, 23:22

Thanks for your quick reply and putting me at ease, so now I'll liberate the laptop from the lad when he's at school and pop the inv V on it and have a flick around. Happy days!
The USB extensions a cracking idea, i'll have a route through my box of bits im sure there's one somewhere.

User avatar
radiogaga
Top Poster
Top Poster
Posts: 1465
Joined: 04 Sep 2010, 20:37
Call Sign: 26TM399

Re: RTL2832U dongle antenna worries

Post by radiogaga » 06 Sep 2018, 23:41

You would be far better to try with a VHF and UHF antenna and give that a go. Loads of airband and Marine stuff to have a go at, or 446 up on UHF.... That’s just to start.


Here’s some fun uses

https://www.rtl-sdr.com/rtl-sdr-tutoria ... te-images/

https://www.rtl-sdr.com/tempestsdr-a-sd ... diated-rf/

https://www.welle.io

This really is scratching the surface
26TM399 Hampshire and Isle of Wight
30TM399 Northern Costa Blanca

User avatar
loudassassin
Super Member
Super Member
Posts: 121
Joined: 22 Jan 2012, 19:28
Location: North Staffs

Re: RTL2832U dongle antenna worries

Post by loudassassin » 07 Sep 2018, 08:22

Thanks for the links, the unintentional RF looks interesting. The weather satellite is something ive been wanting to have a go at, i used to try and get HF fax when i had my FRG7 comms receiver.
I'll perhaps have a go at making a vhf and a uhf antenna for receiving, i do enjoy a little project now and then and there's got to be loads of info on home brew antenna's on here to go at.
I've been using my dongle with its tiny supplied antenna with ads-scope for plotting planes on a map and also general flicking through, im looking forward to seeing what different antenna's will drag in.

User avatar
radiogaga
Top Poster
Top Poster
Posts: 1465
Joined: 04 Sep 2010, 20:37
Call Sign: 26TM399

Re: RTL2832U dongle antenna worries

Post by radiogaga » 07 Sep 2018, 09:10

You'd be surprised how much a small mod to that supplied antenna can make to ADSB. If it looks like this, try cutting it down.
cuttign quarter waves back.jpg
or better still keep that as it as a knock up a free standing spider for ADSB
16550012467_1dbb68602f.jpg

For VHF and UHF, keep the antennas vertically polarised.

Here is a good link: https://m0ukd.com/calculators/slim-jim- ... alculator/

For 137 weather satellite, I use this http://lna4all.blogspot.com/2017/02/diy ... tenna.html

Keep that one horizontal.
You do not have the required permissions to view the files attached to this post.
26TM399 Hampshire and Isle of Wight
30TM399 Northern Costa Blanca

User avatar
loudassassin
Super Member
Super Member
Posts: 121
Joined: 22 Jan 2012, 19:28
Location: North Staffs

Re: RTL2832U dongle antenna worries

Post by loudassassin » 07 Sep 2018, 12:17

The scrounge for materials begins, i like to try and recycle stuff if possible. I've got a couple of old mobile antennas that can be butchered for parts for the spider one. The J-pole looks easy enough to make and as its only for receiving i shouldn't encounter any problems there.
Again thanks for the links and all your help :)

User avatar
radiogaga
Top Poster
Top Poster
Posts: 1465
Joined: 04 Sep 2010, 20:37
Call Sign: 26TM399

Re: RTL2832U dongle antenna worries

Post by radiogaga » 07 Sep 2018, 15:36

No worries. I'm a bit obsessed with the SDR stuff.
26TM399 Hampshire and Isle of Wight
30TM399 Northern Costa Blanca

Post Reply

Who is online

Users browsing this forum: No registered users and 2 guests