Become a Society Insider

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Jun 152011
 

Want to be kept up to date with news and events?  Join the LPFM Society Insiders mailing list. You will be notified of upcoming meetings, news and events. Simply click here and sign up. You can choose to receive each email individually or a daily digest. Do it now and become a Society Insider.

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The Complaint That Wasn’t

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Jun 092011
 

The Society recently received a complaint from a new member that another LPFM Station was swamping his signal. A visit by a Society member revealed a different story. The Society member reported back:

  • The problem is in your antenna/coax
  • Impedance was 24 ohms. should be 50
  • SWR 2.1:1. should be 1.5: max. (But  better if closer to 1.1:1)
  • Z=10. Z should be as close to 0 as possible but certainly below 3 or  4
  • The coax RG58 is 6 years + old and looks a bit suspect.
  • the connections to the JPole appear to be perished and probably letting water into the cable..
  • I would remake the RF choke with 4 turns at 100 mm dia rather than the 2 turns as at present.

It has been reported that the station is now back on air. Another great result from the Society.

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 Posted by on 09 Jun 2011 at 08:03

Illegal West Auckland Station Located

 News  Comments Off on Illegal West Auckland Station Located
Jun 082011
 

Great work by Society members to locate and educate the illegal station in West Auckland. A frequency change and  power adjustment sees them broadcating within the GURL

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Jun 062011
 

There is a new LPFM station broadcasting illegally in West Auckland on 87.5MHZ. The station identifying themselves as Amped or Amp’d FM or broadcasting outside the terms of the GURL. 87.5 is not an available frequency. Society members have idrntified the signal to be coming from around Glengarry Rd.

If you have any information on how to conatact this station please email the webmaster.

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Samson Audio Meteor Mic

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Apr 032011
 

Future of Audio Recording?Looking for a new way to record content for your radio station?. Well look no further. Samson Audio have released the Meteor Mic based loosly on the look and feel of the Shure 55SH. Connect the Meteor Mic  to your iDevice running MultiTrackDAW from Harmonicdog and you have a full digital multitrack with portable microphone.

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Pira 75 Analyzer

 Member Services, News  Comments Off on Pira 75 Analyzer
Nov 282010
 

One of the most challenging elements of FM broadcasting is accurately setting up modulation levels. Schedule 1 h of the GURL specifies

(h) Unwanted emissions shall not exceed the limits as follows;

Unwanted Emission            Frequency Range                    Spectrum Analyser
Limits – in the                         from carrier                              Resolution  Bandwidth
resolution bandwidth

-25 dBW                                   128 to 240 kHz                          Not to exceed 10 kHz*
-35 dBW                                   240 to 600 kHz                         Not to exceed 100 kHz*
-56 dBW                                   > 600 kHz                                    100 kHz

* The spectrum analyser shall be set for 5 minute maximum hold.

But what does all this mean? I can guarantee most LPFM broadcasters just plug everything in and adjust the volume to sound similar to another station. The danger of this approach is that many stations use specialised and expensive processing. High volumes are obtained by reducing the dynamic range. Trying to match the volume of a commercial radio station will inevitably lead you to breaching the GURL. With a PIRA75 modualtion monitor you can set your modualtion levels correctly. It will also assist with the ability to deal with interference complaints. This will be available to members.

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Coverage map service now available to members

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Nov 132010
 

LPFM Society members can now request coverage maps here. If you are not a member you can join here. All coverage maps will be posted here unless a full member requests privacy.

Here is a YouTube video to show how to create and export a KMZ

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