Interest in broadcasting stuff?

[arjoll]

Mid Dome STL installed

This is the (almost) finished external installation at Mid Dome that was on-air at 6pm yesterday. We were out of daylight - apologies for the scratchy photo. It shows the extra bracing.

Just to recap, that's an Aldena ASR03.02.317 3 element yagi and Scala PR450 paraflector. Both running on Andrew LDF4-50A Heliax.

Our next step is to add some ice protection - something above the parafletctor and the feed to the yagi to prevent falling ice damaging our equipment.

 

[arjoll]

Mid Dome cabling

You'd have to be fanatical to be interested in this picture. Our cable entering the hut - the two leftmost cables are the feeds to our yagi and paraflector. Using Andrew LDF4-50A heliax and grounding kits. Enjoy

 

[arjoll]

Mid Dome completed rack

This is the front of our rack, on-air:

• RVR RXRL-NV STL receiver
• RVR TEX LCD 30 watt exciter
• RVR PJ300M power amplifier
• RVR FFC05 triple cavity filter

We're running 29dBW EIRP on 100.0 MHz.

 

[arjoll]

last one - the back of the rack!

Finally the last one - the back of the rack at Mid Dome, nice and tidy!

 

[The Ghost of FM]

Very nice photo-essay!

What type of programing does the station do?

Is it strictly just a stream of mp3 music or is there news and other reporting that is done?

Does your station have a website and/or web-cast?

Thanks for giving us a glimpse into the world of broadcast FM.

Cheers!

 

[jpmorris]

Out of interest, what is the power source for the transmitter?
I'm guessing it needs a multi-phase supply from the power grid. Can it run natively off 415v (or whatever the local supply is) or does it need to be stepped up to something higher first?

 

[arjoll]

Winter on Mid Dome

Forgot to post this one before. This is a photo taken last winter (about June-July) by another technician at the site. Access after the first big snowfall (late May) is by helecopter until things thaw about October.

 

[arjoll]

Very nice photo-essay!

Thanks!

What type of programing does the station do? Is it strictly just a stream of mp3 music or is there news and other reporting that is done? Does your station have a website and/or web-cast?

It's a Christian top 40/rock station with a 20-35 core demographic operated by Rhema Broadcasting Group Inc.

While its primarily music radio, there is a news service (from IRN, owned by Canwest), Sunday night talkback and the usual wacky breakfast show etc that you'd expect on a station with this target audience.

The website (and feed) is at http://www.lifefm.co.nz.

Their playout system is NextGen - they've just switched from BSI WaveStation. There's processing at the head end with another Aphex 2020, so we do very mild compression but a bit more bass processing and peak limiting at this end.

Thanks for giving us a glimpse into the world of broadcast FM. Cheers!

No problems! Its nice to know someone else is interested in this. After showing my wife the first couple of photos or starting out a conversation with "there's this really cool piece of equipment" her eyes tend to start glazing over!

Cya
Andrew

 

[arjoll]

Out of interest, what is the power source for the transmitter? I'm guessing it needs a multi-phase supply from the power grid. Can it run natively off 415v (or whatever the local supply is) or does it need to be stepped up to something higher first?

Hi jpmorris!

The power amps are only 300 watts, so everything's just running on standard single phase power - 230 V 50 Hz. Our draw is in the region of 1 kW at each broadcast site, and less than 100 watts at the link site.

Mid Dome has three phase available - there is a 11 kV feed up the hill - but after seeing the gear in four of the huts there there's not really anything that uses this kind of supply. Vodafone have just installed a huge new cellphone and microwave site there (pic attached) which I guess may be running three phase.

Cya
Andrew

 

[The Ghost of FM]

I lifted this snap from your station's web-site...too funny!

 

[Beck]

Nice info and pics. Who built the wood rack frame? It gives me some ideas.

-Tim

 

[arjoll]

Nice info and pics. Who built the wood rack frame? It gives me some ideas.

Thanks. The wooden rack frame was built by one of the other Trustees, John Dennison, who did all of the engineering work etc for the sites. I screwed the racking onto the side.

This method is one I picked up from Sono Sound when they did the installation at the local Access Radio station, where I was a board member from '92 to '99. Very cheap way of making a rack, and entirely acceptable for this kind of site. A bit rough for a studio though

We had the option of a proper steel rack for free, but the freight was going to be around NZ$200 to get it down from Auckland.

 

[arjoll]

Ice and snow

If you're from the right half of the world you'll know that we're heading into winter now.

This is what our site looked like after the first significant snowfall at our transmitter site this year. I've just been up there to investigate why we went off air - turns our our Italian aerial decided to send 75 watts of our power straight back to the transmitter, causing it to shut down!

We're working on a solution, but after a very, very scarey 4WD trip (2.5 hours up, 1.5 hours down - 7 km of road climbing about 1300m vertically ) we've reduced power to try to stay on-air and we'll use a helicopter next time!

 

[arjoll]

This is what another tower on the site looked like.

 

[arjoll]

....and this was the track, notice the lack of anything to the right. I was walking behind the vehicle so that if it fell of the track I could use my cellphone to get help for the injured driver. Seriously.