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From: G8MNY@GB7CIP.#32.GBR.EURO
To : BCAST@WW

Hi Readers, Updated 6/19
After 16 years of doing Commercial Radio Broadcasts with the UK's expensive 1 month only, Restricted Service Licences (RSLs), a group of enthusiasts (G4WGD G8MNY G6IXM G3TWJ G3WBQ M0JCR M1PFS & non hams), eventually won a 5-year VHF Community licence, on the 2nd attempt. SUSY RADIO (SUssex & SurreY) went live on 15/7/12, (20/6/12 On test). Now into it's 2nd 5 years Licence, & has just recieved a 3dB Tx licence uplift, to 50W ERP H & V. This means better cooling for Tx outdoor box needed, as 2x as much heat to loose! The increase will slightly improve some of the poor signal areas, on a flat earth @ VHF that would double the coverage area.


The project is all volunteers (>60 presenters have been on & it is planned to employ a development manager soon) & a very low budget, higher budget projects often fail! Also the original directors live in service area, just 2 of the reasons why we won over a rival bidder. (The rival went on to fail on UK's very expensive DAB platform!)

Seven presenters & 2 directors have left, several for paying jobs in broadcasting with the help of SUSY training & experience on their CVs.

The station is live up to 17 hr/day 24/7, with some pre-recorded & some syndicated programmes, night time uses a fully automated computer system. The station has kept going with only the odd outages, mainly due to Tx site mains (no UPS @ remote Tx site). Studio A, has a 4 hr 1kW "on line" UPS & smaller Studio B a normal switched 20 min 1kW UPS, both HF pulse width (class D) sine wave type. There is backup MP3 10hr loop playout system @ the Tx site too, just in case of dual uplink failure.

There are many evening specialist programs, as well as live Outside Broadcasts (5000 people at some), programs with highlights of the year etc. & also the odd commissioned program like the popular WW1 "Village at war" series, & some shared programs such as Remembrance Services with other broadcasters, & news stories with BBC local radio.

C O M M U N I T Y L I C E N C E
Unlike RSLs, permanent stations are technically inspected (like a car MOT) before being allowed on air. E.g. Modelled Aerial Polar Patterns, Calculated ERP, Hazard ERP distance, Measured on site Tx Mixing Products, Harmonics, Carrier Frequency, Spectrum Bandwidth, Peak Deviation, Stereo Pilot frequency & it's FM deviation, RDS data & its FM deviation, are all scrutinised. On our test day the spectrum analyser was VERY FULL of large signals from the scores of nearby Tx on the same hilltop (a hedge hog comes to mind), but no unwanted extra ones when our Tx was on. :-)

These Licences are ONLY for "not for profit Limited Companies", & there are commercial limits (that can change year to year) on the station's earnings, so not to encroach on main commercial station's pickings in an area.
The licences now permit low power up to 50W ERP Horizontal & Vertical (100W slant). The 1st Ofcom Frequency offered, would have jammed nearby E.Grinstead's community station which is inside our rather large service area! The 2nd offering of 103.4MHz, OMNI coverage from our Tx site was not allowed! So I had to design a simple, but high specification aerial, to meet both Ofcom & 750ft hilltop cottage Tx site requirements.

M Y S P E C I A L A E R I A L
After a lot of computer models with MMANA-gal design tool, I came up with a very modest slant polarised single driven element & reflector aerial (not a 2el Yagi/ZL), that "JUST" met all the restrictions, producing a complex slant "peanut shaped" 3D pattern with a deep null to the north....

OFCOM's ERP RESTRICTIONS

The north limit NORTH 90° SKY 20° The sky restriction is to
is to stop any \ <2W / \<20W/ reduce Aircraft Rx images. possible _-14dB_ -4dB_.-─'─. This is despite 2x 7.6kW interference / '\ /' \ ·' \ slant high power Band2
to co-channel ( ° ) N \. │ S Tx @ 200ft on the same hill, Heart FM in ▌ plan ▐ ~~~°side view~~~~ & the presence of South Henley & to ▐ ▌ London's NATS (aircraft) 103.3MHz London \ / Tx Site mast (not Rx).
Greek Radio. '·._.·' something Ofcom's inspecting
50W ERP SOUTH engineer was unaware of!

This is all without significantly damaging the main southerly service area. The North ERP is ONLY ~ 200mW (other than the scatter from 3 nearby 200ft masts), but the ERP to East & West is unfortunately down to about 16W.

C O V E R A G E A R E A
The aerial pattern plus the North Downs terrain give a semicircular coverage of 350 square miles (768 sq km), which is EXTREMLY GOOD for 50W ERP Band2 signal!

This is all down to the Tx site having a 480ft (143m) immediate drop to the service area.
\│/other\│/ │ TYPICAL LOW AERIAL
SUSY's Aerial # 200ft # HIGHT COVERAGE
. \│/ # masts # │
. · '·.:;▐▀ @780ft ASL Omni
. · ' . · '.·'·; ▌ COTTAGE │ Aerial
. · ' . · ' .·' ·'; ▐ ON TOP OF [M25] .\│/.
. · ' . · ' .·' ·' ; ▌REIGATE HILL [J8] │ . ·.'·.'#'.·'.· .
SUSY's LARGE SOUTHERLY SERVICE AREA

However this frequency has a lot of QRM from the adjacent LGR Tx at Alexandra Palace N.London, & this has jammed the wanted N & E coverage from Banstead to Caterham. This was not predicted to be so heavy at time of the frequency acceptance! Other stations outside the area on, or +/-100kHz (1/3 ch away), do limit the weak signal coverage area. e.g. Brighton's Heart also on 103.4MHz.

Listener feedback & our roadside "usable signal" research shows coverage is very close to predicted field strength maps, which covers towns:- Reigate, Redhill, Horley, Crawley, Gatwick, S.Dorking & E.Grinstead. But Burgh Heath & Banstead just to the north of the Tx is not covered ().

M A P (Banstead) (Hooley) (Caterham QRM)
(Burgh Heath) ______
_______ |STUDIO|
|Reigate| Merstham~~~~~~ (Westerham)
|Hill TX| Oxtead
(north) ~~~~~~~ Godstone
Dorking Reigate Redhill Bletchingley
Westcott
Salfords
(Edenbridge)
Outwood
Lingfield
Horley Smallfield
Hookwood
Charwood
Gatwick
Copthorne East Grinstead
Crawley

Peas Pottage (Forest Row)

The coverage area is about half that of the nearby QRO "BBC SC" & "HEART FM" stations (54dBuV/m @10m high field strength Ofcom map), with only 1.3% of their radiated power!

Dx Reception reports from an "identified SUSY" just south of Calais France, & listenable with a large 6el aerial in Utrecht Holland (tropo), other Dx reports would be appreciated.

My QTH in Croydon to the NE is well outside the service area, so I use a large dedicated 6el beam @ 10m pointing SSW. I designed it for just this frequency with highest front to back ratio, to remove most of the LGR QRM, as well as Henley's Heart FM. However with tropo I Rx BBC Devon 15kW ERP quite often, or BBC Essex 103.5 12kW. And in summer I sometimes Rx French, or even Spanish QRM with sporadic E from a station in Granada, at same beam heading wiping out SUSY Rx!

F M S T E R E O S I G N A L
This is full spec. ±75kHz deviation, Zenith GE 19kHz pilot tone Stereo system, & 57kHz Radio Data System (1136b/s bi-phase) with traffic flag, but no other data, as the kit is all remote. In all this produces a 266kHz wide signal!
The amount of high quality AF "BROADCAST LIMITING" is typically 12dB peak on music, & 18dB on speech. Which is a lot less extreme, or fast decay (mulitple time constants used) as many stations use, so there is still quite a "GOOD DYNAMIC RANGE" listening experience to please the ear.

O U T S I D E B R O A D C A S T S
The Tx site uplink system I designed, automatically swaps between the high quality stereo studio system & the simpler mono OB system, & it works very well. 4G Internet options have been used, but never that simple or reliable, however some programming & multiple streaming is now done live from local football matches with a 15 second link delay!
Many OBs have been done with Sat news too, all with simple Mono hifi VHF RF link.. From Crawley Vintage Car run, K2, Remembrance Services, Horley Carnival day, East Grinstead, Outwood, etc. Many of the highlights are on the internet player.

P C s
They get everywhere nowadays, the main Studio has 5 with low energy screens. The music PC runs Myriad software (Greek for 10000) & it can be fully automated with IDs, Ads & SKY Sat News, the 2nd is for DJ Internet access (e.g. Text, Facebook Emails, Wx, Traffic, News updates), 3rd is for Internet uplink streaming, & 4th is for off air logging (a legal requirement) it makes a 83MB mp3 file per hour! The 5th is for co presenter use. The 2nd studio has 2, & office 1.

I N T E R N E T
From "susyradio.com" Streamed live (Internet listen live option) at 192kB/s stereo is normally feed direct with a simple limiter, or live "off air" signal (for OBs etc). Currently we have 200 full PC streaming ports (500 on some programmes) & loads more ports on the reduced quality Iphone/Ipad feeds & they both can be heavily used. E.g. Maxing out for SUSY's "Village at War" series & Sports Programmes. After 4 years of our ever improving website, all fairly trouble free.

Listener feedback & requests etc, studio Tel 01737 271034, Text+44 7480 025010 or EMAIL "studio@susyradio", "facebook.com/susyradio" & "tweet@susyradio".

For general engineering information, packet me (QTHR).

A U D I A N C E S I Z E
This is difficult to judge without a proper costly survey, but due to the Internet access there are some accepted estimates of 25x that for the actual radio listeners. In the 1st 2 months we saw 4k unique IDs logged on to listen in (only 50 ports then), so that makes the initial audience around 80k, but that is not a "weekly 20 min for a listener" figure! Other estimates ~ 10-20k.

Programme feedback is good with even a weekly 2 hour program can get 47 live Facebook comments. Some of the phone quizzes have also had the phone ringing immediately (listeners with speed dial?). All very good audience feedback.

T A L K S
Needless to say, building studios, inter-studio comms, silent door bells, broadcast kit design & engineering, O.B. links, Sky news sat sources, On air phone systems, Computer audio sources, Computer logging, On line 4hr 1kW UPS, HiFi audio sources, Studio mixers, Stereo broadcast limiters, Stereo & RDS encoders, Fixed broadcast links, Remote Automatic backup programme switching sources, Broadcast Tx, Backup Tx, Tx & Link Aerials systems, Complex IT, & Air conditioning, are just a little bit different from mainstream Amateur Radio.

If anyone or a club would like a technical visit (or local talk?) or would like to be involved with the station please RSVP me, or Email the station.

F U T H E R R E A D I N G
See my associated tech buls on "1W @ 531kHz MW station system", "AM Broadcast Radio Principles", "FM Stereo Radio Principles", "FM Stereo QRM", "Broadband 6el Yagi for Band2", & "Band2 6el Narrow band Yagi".


73 de John (eng team) G8MNY @ GB7CIP

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