THE TRANSMISSION GALLERY
|Photos by Andrew Wroblewski||Page last updated: 2019-01-03|
|Andy Wrob is delighted to be able to share these photos and this story with mb21, for a new radio station in Southport (Merseyside) called Mighty Radio 107.9fm.|
Andy writes: "Absolute thanks to David "T" from Ofcom, for all his great help and guidance with this, and to the church itself (Anne and Ray etc) for helping us and guiding us into achieving almost the impossible, which was to set up a transmission site without any drilling of holes (due to the church being a listed building).
Initially we were going to use an H dipole, but it gets very windy up there on top of the church, so we settled for a vertical fm aerial instead from Radio Structures. Then came the problem of where to place the transmission gear and a way to receive the signal from the studio a mile away. We could not place this receiving gear on the roof of the church, due to weather, rain, freeze, elements and so on, so the church people found a small "shed" for us, 4'x4', which was literally dangling above the large church bell half way down the church tower, and this houses our (superb!) transmission gear, which was a bit of a squeeze for all of us when the representative of Ofcom was here testing it all for us.
So from the aerial on the roof of the church to the transmitter, we used 45 metres (yes 45 metres) of rg213u cable, (the cable had to follow a special path so it did not spoil the church inner view itself), this resulted in the need to send 45 watts up there to get 25 watts at the aerial. (rg213u loses 7.2db at 100 MHz per 100 metres).
Because no drilling was allowed, we could not fit a conventional STL to obtain the audio from the mighty studio a mile away, so we used a pair of wonderful Ubiquiti NanoStation Loco M5's to send and receive the audio, and thanks to a small opening in the church slats half way up the tower, this fitted perfectly without the need to drill holes.
The transmitter is a TEM 100 watt running at 45 watts, and there are two standby transmitters, in case an Act of God sends a bolt of the dreaded lightning to the aerial at any time (although we have made sure it is earthed, as you will see by the photos). The two standby units are a Cybermax 25watt from PCS electronics in Slovenia, and a BW 150watt V3 running again at 45 watts - and all fed by the wonderful BW encore audio processor, which makes us sound as loud as the local radio stations, without going over that 75khz deviation. (Thank you again to BW & Broadcast Warehouse).
Our RDS call sign is 'MightyFM' (sadly too many characters in 'Mighty Radio'), We are really lucky to be able to send out 25 watts from such an incredible height to entertain our listeners in Southport. All being well, you might just be able to make out the small room we use for the TX equipment, which is situated just above the biggest and loudest church bell that you have ever seen in your life. Great days ahead we hope, after months and months of "head scratching". Andy Wrob
|Church in Southport, you might just be able to make out the FM aerial at the top there.|
|The aerial equipment ready to take to the church, including the directional coupler, required by Ofcom to test the equipment.|
|The 100 metre of RG213U cable needed to link the high aerial to the transmission equipment way down below.|
|Here we see Baz, who helped Andy all along the way, including carrying sandbags and everything else up miles of stairs in the church tower.|
|Here is Andy himself, admiring the aerial, on a very windy day; as you can see there is some relief from the elements there.|
|FM antenna from Radio Structures, supported by the existing church "flag" mast, and supported by several sand bags, and really has withstood many miles of gales!|
|Now that the aerial is erected, time to bring the rg213u cable down down down to the transmission "shed" via many many flights of stairs.|
|And even more stairs to bring the antenna cable down, without spoiling the inside of the church.|
|And finally the rg213u cable ends in a small 4' x 4' shed above the church bell. Just visible is one of the standby transmitters in a metal case.|
|And the shed itself, literally above the loudest church bell you have ever heard. Wonderful! (This is why we all love radio)|
|Now comes the STL receiving equipment, to link the "Mighty FM" studio to the church TX, we were going to use this 5.8 GHz link, but no drilling allowed out of respect to the church fabric.... so we found an alternative way.|
|So we settled for a pair of Ubiquiti NanoStation Loco M5's to receive the audio from the mighty studios a mile away|
|This is a standby transmitter in a metal box, from PCS electronics in Slovenia, you might just be able to make out, also, the directional coupler required for testing and calibration.|
|Quick view of the standby transmitter being tested.|
|Our main transmitter, the impressive TEM 100 watt from Italy, running at 45 watts to get 25 watts at the FM aerial.|
|This is the rear of the TEM tranmitter, prior to install in the church.|
|One of the other standby transmitters, the excellent all in one BW V3 TX 150 watt, with RDS and audio processing, this will be tested at request, should the other two tested TXs fail in any way (eg lightning).|
|The rear of standby transmitter number 3 (subject to approval), a BW TX V3 150watt (with built in RDS, Audio Processing).|
|And here we are finally running the main transmitter (TEM from Italy) from a BW Broadcast encore audio processor, for top-flight FM sound, all within that 75khz deviation.|
|And finally, the audio processor (BW mini encore) which is vital, to make us sound as good as local larger radio stations; believe it or not, this costs as much as the TEM transmitter, and worth every penny.|
|And finally, thank you to all who helped make this possible, to my mate Baz the Boffin for his incredible help (muscle power), and to David T from Ofcom for spending an entire day with us and for helping all along the way too in the previous months, and to the management of mighty radio, Dave the mighty Quinn, Trevor Ford and Paul Tasker. Hope you enjoyed seeing this insight into a radio install, one that could well have been impossible to complete without some careful imaginative planning. Andy Wrob|
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