PROception PROMOD1 Instruction Manual page 2

Mains power supply:
The modulator is supplied with a fi ed mains plug and may be plugged directly into a 13 A (BS 1363)
socket outlet. If socket outlets of a different type are in use, please refer to the safety instruc ons on
page 4. The mains plug should remain readily accessible to permit disconnec on of the unit from the
supply.
Alterna vely the plug may be cut off and the modulator wired into a readily accessible fused
connec on unit, fi ed with an approved 3 A fuse to BS 1362. This method of connec on is
recommended for permanent distribu on system applica ons, since it reduces the risk of tampering
and accidental disconnec on. Please note: A readily accessible isola ng switch should be provided to
allow the unit to be disconnected from the supply when necessary.
If the modulator is not connected to the mains using the fused plug supplied, or a fused connec on
unit, it must be protected by means of a fuse or MCB at the final distribu on board of ra ng not
exceeding 6 A. Please note: A readily accessible isola ng switch should be provided to allow the unit to
be disconnected from the supply when necessary.
Any fixed wiring installed to supply power to this modulator should comply with BS 7671 (IEE wiring
regula ons) and, where relevant, Part P of the building regula ons. The proMOD1 Mk2 modulator is of
Class II construc on and does not require a protec ve earth connec on. This does not obviate the
need to provide a circuit protec ve (earth) conductor in the supply wiring, as required by BS 7671.
System equipoten al bonding:
Distribu on systems supplying signals to more than one household should comply with the safety
requirements of EN 60728‐11. This effec vely requires earthed equipoten al bonding of the system.
(The use of isolated outlet plates is no longer recommended since they compromise screening
integrity and allow ingress of interference.) Bonding may be effected using a proBAR5 equipoten al
bonding bar.
Se ng the output channel number:
The channel se ng bu ons on the front of the unit are normally locked to protect against accidental
change or tampering. To change the output channel se ng proceed as follows:
1.Press and hold both bu ons together for about two seconds. The channel no. display will start to
flash.
2.While the display is flashing, adjust the channel no. as required using the sort bu on.
3.When the display stops flashing (about two seconds a er the last bu on press) the new channel
se ng is stored in the non‐vola le memory.
4.Repeat from Step 1 if necessary, to try a different channel, or if the me‐out occurred too soon.
If the output channel is changed a er installa on, all TV receivers which are using the modulators
output will need to have their appropriate channel se ngs retuned.
Notes on channel selec on:
Choice of an appropriate modulator channel se ng is important to avoid interference problems.

The modulator output should not be set on the same channel as any off‐air analogue or digital
signal carried on the system. Using a channel which coincides with an off‐air DTT signal is a
common cause of a noisy looking modulator picture.

Also avoid adjacent channels (N±1 rela onship).

Avoid any combina on which results in signals spaced 5 channels apart (N±5 rela onship).

The old avoid N±9 rule can usually be ignored, due to the improved image rejec on of modern
TVs.

Any other modulators in the same system (in VCRs, etc.) are subject to the same rules, which also
apply between modulators.

To check for interference to other channels caused by the modulator, disconnect the RF IN and
RF OUT cables and link them together using a back‐to‐back adapter.

To check for interference caused by an off‐air or other upstream system‐generated signal to
the modulators output channel, unplug or disable the relevant input feed to RF IN.
Informa on on UK TV transmi er channel numbers can be found at the following Web URLs:
h p://www.bbc.co.uk/recep on/transmi ers/tv_trans/index.shtml
h p://www.ofcom.org.uk/sta c/recep on_advice/index.asp.html
TV System System I (ITU‐R Rec. BT.470)(Note 1)
Modula on Spectrum Type Double‐sideband
Output UHF channel E21‐E69 (set from front panel, stored in non‐vola le memory)
Output Signal Level 75 dBµV (typical, peak sync)
RF loop‐through bandwidth 47‐862 MHz
RF loop‐through gain 1.5dB
Video input level 1V p‐p (internal 75 Ω termina on)
Audio input level 200 mV RMS sine for ± 20 KHz peak devia on (1 KHz modula ng
frequency) (note 2)
Power requirement 230V AC 50Hz at 4W (5.5VA), supplied with fi ed mains plug to BS 1363
1.Tolerances given in the ITU‐R Recommenda on are not applicable.
2.The L & R inputs are added to provide a mono signal for modula on. (Quoted sensi vity applies with
both channels driven.)