Geekzone: technology news, blogs, forums
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.
Buying anything on Amazon? Please use the Geekzone Amazon aff link.

291 posts

Ultimate Geek
+1 received by user: 9

Topic # 107319 9-Aug-2012 11:15 Send private message

Hi there guys.

I've been reading up on the subject of DXing FM stations. I was watching a video when a guy from Adelaide, was listening to ZM from Palmerston North, and The Breeze from Auckland with some super sensitive Tuner and antenna setup.

DXing looks like a hobby that doesn't cost the earth, and if it really doesn't it's not a bad hobby for me to do in the day.

Just wondering, are their any guys on Geekzone who do that sort of thing, and are able to tell me where to get the cheapest gear available  that will do the job?

Also say I did get that setup, what Out of range transmissions would I be likely to receive, and from where?


Create new topic
3639 posts

Uber Geek
+1 received by user: 533


  Reply # 669988 9-Aug-2012 11:19 Send private message

You could just get an app for a smartphone and listen :)

87 posts

Master Geek
+1 received by user: 9

  Reply # 669997 9-Aug-2012 11:44 Send private message

Ordinarily FM is limited to line-of-sight propagation owing to the fact that - at VHF frequencies, the signal is not reflected back from the upper atmosphere.

Around the Earth in the upper atmosphere is a layer (or actually, several layers) of charged particles called the ionosphere. The different layers of the ionosphere reflect different parts of the radio spectrum depending on the time of day (the sun has a part to play in this too... the charged particles get their charge from it and lose them at different rates at night...)

The ionosphere is what makes intercontinental "shortwave" transmission possible - stick a transmitter in Australia and a receiver in China and give it a few bounces along the way and the signal is received in China.

There are certain frequencies or bands of frequencies that are reflected, some strongly, others not so.

Ordinarily the VHF waves of TV and FM transmissions aren't reflected, which is great because you can re-use the same FM frequency in two places without interference provided they're far enough away from each other.

However, at times approaching the peak of the 11-year sunspot cycle, the ionosphere gets gets charged and starts doing unpredictable things. Sometimes it starts reflecting transmissions from great distances - think of it like a wormhole on Star Trek - except it carries radio waves only :D

The Technical term for this is "Sporadic E" propagation (because it's the E layer in the ionopshere that's responsible) but most radio operators just call it "skip".

When the "skip" is running, you don't need any fancy equipment to receive distant transmissions, a headphone radio will do it... conversely, if the skip is not happening, there is no radio and antenna system on Earth that will allow you to receive an NZ FM transmission in Australia.

So the long and short of this little lecture is - you don't need any fancy equipment, other than lots of time of course... bit like watching the weather really!


4841 posts

Uber Geek
+1 received by user: 296


  Reply # 670027 9-Aug-2012 12:40 Send private message

PaulZA: I was watching a video when a guy from Adelaide, was listening to ZM from Palmerston North, and The Breeze from Auckland with some super sensitive Tuner and antenna setup.


1586 posts

Uber Geek
+1 received by user: 62

  Reply # 670149 9-Aug-2012 15:52 Send private message

Most Freeview cards for your PC have FM radio tuner included.
Just plug one in, set it up then put a decent antenna on your roof. Probably not as sensitive as a decent receiver though.
Check out the Radio/Electronics section (and related magazines) in your local library for antennae and how to build.
You could also get into Amateur Radio very easily. The exam is dead easy now with no Morse requirement. Check with your local Amateur Radio Club (google NZMAA). Most new guys do a weekend course, pass the exam and get their licence in the one weekend. You'll find radio gear on Trademe but Amateur Radio Transmitting gear can only be sold to Licened Amatuers.
Opens up the whole world of Radio Dx.
Cheapest source of good receivers would be places like HRO (Ham Radio Outlet) in USA. Also places in Oz and Hong Kong.

Create new topic

Twitter »
Follow us to receive Twitter updates when new discussions are posted in our forums:

Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:

Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:

Trending now »

Hot discussions in our forums right now:

Bad lower back.
Created by TimA, last reply by MadEngineer on 27-Jan-2015 21:27 (40 replies)
Pages... 2 3

AdBlockers on Geekzone
Created by freitasm, last reply by freitasm on 27-Jan-2015 21:04 (43 replies)
Pages... 2 3

Windows 10 News - 22 Jan
Created by Regs, last reply by tdgeek on 27-Jan-2015 19:52 (116 replies)
Pages... 6 7 8

Police Speed Campaign - Summer 2014/2015
Created by nzkiwiman, last reply by Bung on 27-Jan-2015 18:28 (96 replies)
Pages... 5 6 7

Spark customers get Lightbox free for 12 months
Created by freitasm, last reply by ARK on 27-Jan-2015 16:35 (137 replies)
Pages... 8 9 10

How (not) to run a hotel
Created by MikeAqua, last reply by BTR on 26-Jan-2015 16:06 (68 replies)
Pages... 3 4 5

Police above the law ?
Created by heylinb4nz, last reply by MikeAqua on 26-Jan-2015 14:27 (116 replies)
Pages... 6 7 8

Top Gear Series 22
Created by WyleECoyoteNZ, last reply by Stan on 27-Jan-2015 19:42 (15 replies)

Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.

Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.