Geekzone: technology news, blogs, forums
Guest
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.


Oubadah

676 posts

Ultimate Geek


#84377 29-May-2011 21:28
Send private message

Can anyone recommend a cost effective outdoor (roof mount) FM aerial for radio?

Create new topic
B1GGLZ
1960 posts

Uber Geek


  #475654 30-May-2011 08:42
Send private message

I use a short piece of wire on the end of a length of coax tied to the TV pole with a bit of string. Works fine and cost nothing as I had heaps of ocax in the junk box.

illicit
553 posts

Ultimate Geek


  #475656 30-May-2011 08:46
Send private message

Still got your old VHF TV aerial? Connect that to your radio, most times is more than adequate.

 
 
 
 


mm1352000
1148 posts

Uber Geek

Trusted

  #475847 30-May-2011 18:09
Send private message

I concur with illicit - our combo VHF/UHF aerial picks FM up with no problem.

Oubadah

676 posts

Ultimate Geek


  #475891 30-May-2011 19:22
Send private message

illicit: Still got your old VHF TV aerial? Connect that to your radio, most times is more than adequate.


mm1352000: I concur with illicit - our combo VHF/UHF aerial picks FM up with no problem.


Does this not need some kind of filter? Does it need to be at a 45 degree angle? (I have a feeling I've asked these question before...)

I do have a VHF aerial, and it's in really good nick. 

If the VHF fails, I'll try the wire idea.

EDIT: ah yes, it seems I've repeated my own thread: http://www.geekzone.co.nz/forums.asp?ForumId=34&TopicId=76670

So the VHF at 45 degrees then. I'll try it tomorrow. 

mm1352000
1148 posts

Uber Geek

Trusted

  #475905 30-May-2011 19:46
Send private message

Interesting - never knew about the 45deg thing. Our aerial is pretty much vertical as its purpose is to pick up DVB-T and analog TV signals. It looks like this...although it may not even have that many short pieces. The FM + analog TV + DVB-T is amplified, then combined with satellite signals by a multiswitch, then split 8 ways and 4 ways again on one of the 8 way feeds. All modes work fine. Smile

cyril7
7750 posts

Uber Geek

Trusted
Subscriber

  #475916 30-May-2011 20:01
Send private message

Technically mainline FM transmitters use slant polarisation this means they work well with a mixed receive antenna, ie does not matter if H or V there is only a 3db penalty unless slanted 90deg out.

So as others have said a BandI/III TV antenna will typically do a good job.

Oh and if you do go for slanting your antenna when standing behind the antenna right side down.

Cyril

richms
23578 posts

Uber Geek

Trusted
Subscriber

  #476035 30-May-2011 23:42
Send private message

VHF antennas work OK so long as they are pointing the right way for FM, but watch out as most amps have an FM trap in them as it us usually way stronger so overload things, so as a result with the trap, they are attenuating the FM not amplifying it.

I got the biggest that there was and it was cheap as, as I wanted to see if I could get one of the LPFM stations. It worked, for about 2 weeks before some bloody ethnic mob started up 0.2 away and overmodulating.




Richard rich.ms

 
 
 
 


B1GGLZ
1960 posts

Uber Geek


  #476082 31-May-2011 09:07
Send private message

mm1352000: .Our aerial is pretty much vertical as its purpose is to pick up DVB-T and analog TV signals. It looks like this...although it may not even have that many short pieces. Smile


If its the same as in the picture then no its not. Its two horizontall polarised antennae stacked one above the other.
If rotated 90 degrees it would be two vertically polarised antennae side by side.

techricky
24 posts

Geek


  #476107 31-May-2011 09:53
Send private message

Most of the Large Transmitting sites are using Circular Polarisation, so rotation of the antenna will not make too much difference.. 
Some are Vertical, but I havent seen any Slant for a while.. There were some in the 80's so they could well still be around.

On the fringe it's definitely worth trying all options of polarisation even with circular as its not often perfect in all directions and objects in the path can reduce one component more than the other.
I've always wanted to try making a circular receiving array with H and V antennas 90° combined for deep fringe testing..

My experience is mostly with Skytower Akl where the large FM1 array is circular and the FM2 is vertical. Within a few kms it can be useful to use a horizontal antenna to reduce the FM2 signals which are quite hot on the ground from the less directional small array..

richms
23578 posts

Uber Geek

Trusted
Subscriber

  #476380 31-May-2011 20:35
Send private message

which ones are on fm2?




Richard rich.ms

tommay69
1 post

Wannabe Geek


  #479968 11-Jun-2011 04:49
Send private message

if you have an exising vhf tv aerial buy a wallplate with fm/vhf splitter - most radios have a 75ohm coax aerial plug - just connect to the fm outlet of the wallplate - easy

pjamieson
429 posts

Ultimate Geek

Trusted
Chorus NZ

  #480063 11-Jun-2011 15:09
Send private message

richms: which ones are on fm2?


Hi techricky, yes which ones are on fm2?

Create new topic




News »

HP unveils new innovations for businesses adapting to rapidly evolving workstyles and workforces
Posted 17-Sep-2020 15:36


GoPro launches new HERO9 Black camera
Posted 17-Sep-2020 09:45


Telecommunications industry launches new 5G Facts website
Posted 17-Sep-2020 07:56


New Zealand ranks 3rd in world in GSMA index
Posted 15-Sep-2020 10:13


Trend Micro Security Suite adds web monitoring to prevent identity theft
Posted 14-Sep-2020 15:37


NVIDIA to acquire Arm for US$ 40 billion
Posted 14-Sep-2020 12:27


Epson launches its next gen A3+ colour EcoTank multi-function printer
Posted 10-Sep-2020 16:08


Sony launches three new native 4K SXRD home cinema projectors
Posted 9-Sep-2020 18:00


Catalyst Cloud brings Kubernetes-based open-source web hosting solution to market
Posted 9-Sep-2020 17:54


Verizon Connect eyes further growth in New Zealand
Posted 8-Sep-2020 09:26


PNY launches XLR8 gaming NVIDIA GeForce RTX 30 series powered by the all-new NVIDIA Ampere architecture
Posted 3-Sep-2020 16:39


NVIDIA delivers greatest-ever generational leap with GeForce RTX 30 Series GPUs
Posted 3-Sep-2020 16:17


Weta Digital advances visual effects and animation in the cloud with AWS
Posted 2-Sep-2020 17:09


Kiwrious lab-in-the-pocket kit designed for schoolchildren
Posted 28-Aug-2020 09:03


Fitbit introduces Sense, its most advanced health smartwatch
Posted 26-Aug-2020 10:14



Geekzone Live »

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


Support Geekzone »

Our community of supporters help make Geekzone possible. Click the button below to join them.

Support Geezone on PressPatron



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.