Talk-Through units: guidelines for use
With effect from Saturday, 18 October 2008, RSGB RAYNET groups no longer need apply for TT Permits. Instead they are asked to submit an annual report of usage (when requested) and immediate reports of any cases of interference cause by or to the units.
Ofcom have declared that Talk-Through is now permitted without the need for a permit to be issued and without the need for the unit to be staffed. However, the RSGB request that all their groups send in an annual return so that use can be monitored. All that is required is to complete and return the information below by 31 January each year, commencing in 2010.
The Group Controller should familiarise him/herself with these notes, and a copy of them should be retained by the operator of the Talk-Through unit.
All operations must be directly supervised by the licensee whose call-sign is being used by the Talk-Through station. That licensee must monitor transmissions on all frequencies in use and be prepared to intervene at once if difficulties arise. With care, it should be possible for station identification announcements to be made without unnecessary disruption of Talk-Through facilities The following identification transmission format is recommended:
This is *callsign* operating Talk-Through for *Group’s name* RAYNET, in support of the *User Service* at *name of event*. This station is located at *location*
The site of the Talk-Through station should be chosen carefully and the lowest RF power compatible with efficient operation used. Care should be especially exercised on sites where there are other non-amateur radio users in the vicinity.
In Band Operation
When used ‘in-band’ on 2 metres, it is recommended that the standard VHF repeater-shift of -600kHz be used, an ‘Emergency Communications’ frequency pair being preferred
a) Wide (7.6 MHz) Split
The frequency pair 430.8000 MHz (Mobile TX) and 438.4000 MHz (Base TX) should be used. Use of this pair should not take place in the immediate vicinity of an existing permanent 7.6 MHz wide-spaced repeater installation or known high-speed data node operating in these frequency areas as there is a likelihood of mutual interference.
b) Narrow (1.6 MHz) Split
It is recommended that the standard UHF repeater shift of +1.6MHz be used, the frequencies of 434.3750 (Mobile TX) and 432.7750 MHz (Base TX) being preferred.
When ‘cross-band’ Talkthrough is employed, it is recommended that only those frequencies identified by the UK Band Plan as being for Emergency Communication (formerly RAYNET) use be utilised. If other frequencies need to be used, care should be taken to avoid those identified for other specialist users and those commonly used as ‘chat channels’. For successful use of Talkthrough, the higher frequency channel chosen must not be a harmonic of the frequency in the lower band used.
It is suggested that Talkthrough equipment be fitted with Transmit Time-Out Timers set to a maximum value of 3 minutes. This may be external or may be an internal pre-settable option in the radio(s) itself. It may also be an idea to encourage individual operators to fit or enable such timers, as a ‘stuck’ or inadvertently enabled PTT at an outstation can unwittingly disrupt Talkthrough operations.
Talk-Through may employ any mode to which the licensee normally has access (e.g. NBFM, CW, SSB, Datamodes etc). Talk-through should normally be on 6m, 2m, or 70cm, although 10m may also be useful in certain conditions, at all times having regard to the band plans.
Annual reports and enquiries should be directed to:
Radio Society of Great Britain
3 Abbey Court
Priory Business Park
Bedford M44 3WH
or by e-mail to g3svlrsgb.org.uk.
Information required on annual report
- Name of group
- Name and contact details of person submitting report
- Name and nature of events
- User service
- Dates of events
- TT unit location
- Frequencies and powers used