Interest in broadcasting stuff?

[arjoll]

Hi - yesterday a Trust I'm on finally got a project running that we've been working on for about five years - broadcasting Life fm throughout the province. Our first transmitter was up and running last year and we got the second one linked up and on-air yesterday.

I know this is homerecording.com not amateurbutenthisiaticbroadcasting.com, so won't post any more unless someone is interested - photos of racks, aerials etc. If anyone's intereted please reply or PM me, otherwise if I hear nothing I'll post nothing!

(this is in the analgoue forum because despite all the research out there, the final stage of broadcasting is still analogue, no matter how many computer based playout systems, Optimod 8400s and digital STL's you throw at it)

Thanks
Andrew

 

[Beck]

Hi - yesterday a Trust I'm on finally got a project running that we've been working on for about five years - broadcasting Life fm throughout the province. Our first transmitter was up and running last year and we got the second one linked up and on-air yesterday.

I know this is homerecording.com not amateurbutenthisiaticbroadcasting.com, so won't post any more unless someone is interested - photos of racks, aerials etc. If anyone's intereted please reply or PM me, otherwise if I hear nothing I'll post nothing!

(this is in the analgoue forum because despite all the research out there, the final stage of broadcasting is still analogue, no matter how many computer based playout systems, Optimod 8400s and digital STL's you throw at it)

Thanks
Andrew

Nice website. I would love to see what equipment you're running.

-Tim

 

[The Ghost of FM]

Me too!

I could stare at equipment all day and often do!

Cheers!

 

[arjoll]

OK, here goes....

Note that this thread doesn't include any cool studio equipment - local breakout is on our longer term plans, but out main aim was just to get the signal on-air. We are picking up a satellite feed of Life fm on Optus B coming from Auckland.

We receive the satellite feed at Richardson Road, near Gore in Eastern Southland, where we broadcast on 99.8 MHz (moved from 92.6 MHz last week). From there we receive it off-air at East Chatton, and use an STL (studio transmitter link) system to beam it over to Mid Dome from where we broadcast to most of the rest of Southland.

Richardson Road is around 220m ASL, Mid Dome is 1478m ASL and has very extreme weather conditions. This is why our 'infill' transmitter for the Gore area is effectively our main location.

Even if you're familiar with New Zealand these places aren't that well known, so here is a map showing their location.

Both sites are running 300 watts base power with 29dBW (794 W) EIRP through directional antennas - Richardson Road points south towards Wyndham, Mid Dome west-south-west towards Invercargill. Because of the sheer height of Mid Dome and the lack of obstruction the signal is of reasonable strength even here in Invercargill (specifically Otatara), about 80km away.

 

[arjoll]

Richardson Road site

Richardson Road, near Gore, is our main receive site.

We receive with a Radyne Comstream ABR202 broadcast receiver (the photos show an ABR200 - the power supply blew up early this year, not unusual with this model) with a temporary 2m prime focus Andrew dish and Comstream PLL LNB. We have a new 1.8m offset dish ready to install.

Life fm (and other RBG brands) are running on a 128kbps MPEG2 stream - not the cleanest feed, but fine for FM broadcast.

Our signal is processed with an Aphex 2020 FM Pro which has been upgraded to Mk II. This is a completely analogue processor with digital control, unlike the Optimod 8200/8400 or Omnia.fm and other all-digital units. Quite frankly the idea of doing broadcast processing (especially the AGC/levelling) in the digital domain is dumb - big local Optimod users often seem to run Compellors beforehand for levelling, and we're getting a sound that is as full, fat and loud as other stations running digital processors, without the harsh, fatigueing sound.

After that we feed an RVR TEX LCD exciter, into an RVR PJ300M amplifier and an RVR FFC05 triple cavity filter, then up a length of Belden 7810A coax into an Aldena ASR03.02.317 three element yagi. This Italian gear is good!

The next posts are photos of our Gore site from the start of the technical installation.

 

[arjoll]

Antenna installation

This is the Aldena ASR03.02.317 yagi being rigged. We used a local sound company I do quite a bit of work with - no way I was climbing up there! The aerial is 10m above ground.

 

[arjoll]

Aerial installed

This is the yagi installed. David Pay is tying the cable to the mast.

 

[arjoll]

Dish installation

The satellite dish is a recycled Andrew aluminium microwave dish. Our installer, Robert Skilton, found was not allowed to install it at home! We are using this until our permanent dish is installed. Its a two metre prime focus dish, quite high off the ground because we don't want to trim the pipe its mounted on until we have the final one in place. The signal is on Optus B at around 11 GHz.

 

[arjoll]

Inside shots

Here is some idiot installing the racking in the hut....(guess who?)

 

[arjoll]

Rack front

The front of our rack. From top to bottom, the PJ300M power amp, TEX LCD exciter, 2020 processor (levelling, processing, four band compressor, split band pre-emphasised limiter, clipper and stereo generator) and ABR200 (now replaced with an ABR202).

 

[arjoll]

Back of the rack

Not the best shot, but this is the back of the rack with my old laptop (for programming the ABR200) at the bottom left.

 

[arjoll]

East Chatton link

This is the view from our linking site to our Mid Dome broadcast site - we're running this on a 915 MHz STL.

 

[arjoll]

Linking equipment

Our equipment is temporarily in the corner of a woolshed! No more shearing until spring (its coming into winter here), but by then we will have a proper hut.

The linking equipment is an Inovonics 630 off-air receiver and an RVR PTRL-NV/HP STL transmitter. The signal is kept composite throughout - no decoding and re-encoding stereo.

 

[arjoll]

Link receive

Our link is received on a Lincrad 5 element FM aerial - pretty standard stuff. Signal strength is excellent - the only reason for the 5 element is directionality, as our two sites are only 200 kHz apart.

 

[arjoll]

Link transmit

Our link uses a Scala PR450 'paraflector' antenna - these have 20 dBi gain, which is huge. We are doing a 54 km path, and are getting 200 watts from about 2.5 watts in (allowing for cable losses).

The STL (and Mid Dome system) use Andrew LDF4-50 Heliax cable - when we installed Richardson Road last year we didn't relalise that this stuff was only fractionally more expensive than the Belden cable we had been using. We still use Belden 7810A for jumpers, etc.

 

[arjoll]

Mid Dome

Southland's terrain ranges from flat, fertile plains to some pretty reasonable mountains - Mid Dome is basically a 1478m mountain at the North end of a long river valley with Invercargill at the other end (refer to the map). Mid Dome can be seen from most of Southland, and from the top you can see basically all of Southland including Bluff Hill (30km south of Invercargill).

This is the installation of our cables on top of Mid Dome.

 

[arjoll]

Mid Dome yagi

We are using the same yagi, an Aldena ASR03.02.317 on Mid Dome. One of our volunteers who helped with rigging maintains other equipment on this site, and says that this aerial is one of the most ruggedly constructed yagi he's seen.

 

[arjoll]

Mid Dome hut

This is the hut we are leasing space in. Note the 4WD - the 7km trip from the main road to the top of the hill is about 1km vertically and takes about 45-50 minutes, not including putting on the chains.

 

[arjoll]

Mid Dome testing

This is our temporary setup on Mid Dome, which went up on the 7th of May.

From top to bottom:

• My wife's cheap MP3 player
• Aphex Compellor
• RVR STL receiver (not in use yet)
• RVR TEX LCD exciter
• RVR PJ300M power amplifier
• RVR FFC05 triple cavity filter

This gave us around 8 hours of test (in mono, as our stereo generation is before the link) and one week of silent carrier to test coverage with. We did this while we waited for the Paraflectors to arrive from the US.

 

[arjoll]

Mid Dome STL rigging

The guys rigging our STL aerial - another Paraflector. We'd found that in the two weeks since we installed the yagi (on 30 April) it had rotated about 10-15 degrees in the prevailing winds. We've added extra bracing to it and the paraflector.