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G8MNY > TECH 10.09.05 13:48l 89 Lines 4686 Bytes #999 (0) @ WW
BID : 61604_GB7CIP
Read: GUEST DL1LCA OE7FMI
Subj: Dx Rx reports wanted for 531KHz
Path: DB0FHN<DB0FOR<DB0SIF<DB0EA<DB0RES<ON0AR<GB7CIP
Sent: 050910/1058Z @:GB7CIP.#32.GBR.EU #:61604 [Caterham] $:61604_GB7CIP
From: G8MNY@GB7CIP.#32.GBR.EU
To : TECH@WW
Hi Readers,
For the 11th year running a group of enthusiasts (several Hams me,
G3TWJ G6IXM G4WGD G4WGZ) have been putting on a local charity fund raising 28
day broadcast radio station (Restricted Service Licence).
It is on air from late August from studios at a youth centre in Merstham near
Redhill Surrey, (Southern tip of M25) again this time back on MW AM. The
station is called "SUSY RADIO" (SUssex & SurreY). Profits (if any) go to local
charities.
The move from VHF to MW came about 4 years ago after a donation of an old Decca
Navigator LW Tx (ex 300KHz aircraft 1KW CW beacon) that could just do the LF
end of MW, a studio site that could take a large wire aerial system, and also
the œ1K reduction in the Licences for MW RSLs.
The restricted 28 day licenced only permits low power of 1W ERP using vertical
polarisation from only "A 20M TALL AERIAL SYSTEM" (radiating bit). Due to our
Tx limitation & objectives we have been given 531KHz. As with the LF ham band,
the LF end of MW band a LARGE amounts of power are needed to obtain a full 1W
ERP from the small radiating vertical radiator, of such a low ground height &
short aerial (1/14 dipole). Ideally one would need a 141M tall copper tower
with a few square km of copper sheet ground mat, to get 1W ERP from a 1W Tx!
The plus of all this effort is that at this end of MW, is that the ground wave
propagation is much bigger than at the other end of the MW band or for VHF
Actually about three times a far as at 1600KHz, about 150kM is possible. The
underlying site's ground conditions have usually been wet (bit of a valley
bottom) so the signal normally gets out quite well. See my bul on 1W MW
STATION's AERIAL SYSTEM.
A strange point of interest is the fact that the 2nd & 3rd harmonics are in
band! I am pleased to say that they are both undetectable at 300M away!
( > -100dB ?)
In EU, 531Khz is the 1st channel on the MW band so a Rx will pick it up first
on scanning etc., and it is a fairly clear frequency in the UK during the day,
but at night there are 100KW Swiss German speaking station, a Spanish station &
one from the Fairo Isle. These dramatically close down coverage area at night
to the typical RSL station coverage due to the heavy slow beating QRM.
The first time we were on MW we had very good reports from far afield such as
YORK, SUNDERLAND, HOLLAND & the south coast, from listeners at QRM free
locations. Mains & SMPS QRM can be a major problem at this end of MW! There is
usually a Dxers Programme on the last week so stay listening for details.
The station is live from the studio except over night when programming will be
from RADIO JACKIE (a W.London local FM station). Unusually for SUSY, this month
the Music will limited to Country & Western for the main programming content,
with youth project presenter slot in the evenings also Local (regional) traffic
information, phone-ins, & IRN News etc.
The various licence costs are high compared to permanent local radio station,
for a 28 day AM RSL station, they are:-
DTI Ofcom Broadcast, about œ1200, (œ2,500 FM)
Performing Rights Society, about œ900, } N.B. not all published
Phonographic Performance, approx œ1150, } material is covered!
Mechanical Copying & Reproduction, œ60. } eg BBC records.
(Band3 1 Watt, RA stereo Link licence œ480. if Tx not co-sited)
In anyone's language this is "an arm and several legs" even for a fund raising
station! Direct sponsorship & adverts from major companies generally covers all
the fixed costs, any profit goes to the nominated charity. A œ28K sunshine
coach has previously been given to a charity partly funded by SUSY RADIO, after
several radio events.
SUSY Radio is also on the Internet "http//www.susyradio.com" where the station
can be found streaming in stereo.
EMAIL studio@susyradio.com
Requests etc, to the studio on Tel 01737 644259.
For general RSL/engineering information packet me or telephone the station
manager Colin (G4WGD) on 01737 643767 Mon-Sat 09:00-17:00 except Wednesdays.
DX Reception reports would be much appreciated to Colin or me.
Needless to say broadcast engineering eg. O.B. links, Digital Satellite links,
Phone systems, Computer Audio sources, Computer logging, Hifi audio sources,
Studio mixers, Stereo/AM limiters, Stereo coders, RDS coders, fixed radio
links, Broadcast Tx & Aerials systems, are just a little bit different from
mainstream Amateur Radio.
If anyone or a club would like a technical visit (or talk?) or would like to be
involved with the station please RSVP me.
73 de John (eng team) G8MNY @ GB7CIP
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