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MK. 301 RECEIVERaf (and MK. 301 PP UNIT for AC POWER SUPPLY).m$-W.7 .:■ - ■

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Mc.301 Receiver

Mc.301 Battery Box

10c.301EP Bjwer Supply Unit

6.5/16" x 3.9/16" xlf

6.5/16" x 3.9/16" x if

5" x 2^" x li"

Weight.

2J- lbs.

2? lba.

l j lbs.

The battery box contains the following ancillary equipment:-

nDea_f Aid" type Earphones, (2)

T Cord for Earphones.

Earth lead fitted with plug and clip, 10 ft.

Aerial fitted with plug and midget insulator, 50 ft.

Extra battery lead assenfoly, 6 ft.

L.T. Battery, TJ.2 Type.

H.T. Battery, B101 Type.

The 1K.301PP ancillary bag contains :-

Universal mains adaptor.

Fuse, 2 amp (4)

Screwdriver

Spare screwa (6)

SJ5CIFICUTICN

Frequency coverage 500 Xc/s - 18.5 Vc/a.

Band 1.2 .3c4 .

500120031107750

1250 Ec/s.3250 Kc/s.7770 Kc/b.

18500 Ec/s.

C i r c u i t .

Valves.

r

The above coils are contained in one coil box andswitching id accomplished by plugging the box intothe rece iver in any one of four pos i t ions.

Four va lve super-heterodyne receiver wi th B.P.0.for c .w. and te lephony recept ion.

D K 9 6 F r e q u e n c y c h a n g e r .D F 7 2 . I . P . A m p l i fi e r .D A F 7 0 D e t e c t o r a n d 1 s t A u d i o A m p l i fi e r .D L 7 5 A u d i o O u t p u t .D F 7 2 B . F . 0 .

Intermediate Frequency 1+6$ Kc/s.

Ca l ib ra t ion : The d ia l i s ca l ib ra ted in 100 d iv i s ions and a char tshewing spot f requencies at every 5 div is ions isat tached to the l id o f the bat tery box.

Output . 1 KW into 15,000 ohms at 1,000 o.p.a.

A e r i a l .

Ea r th .

Power,B a t t e r y

INSTATJATION

E r e c t a n o u t d o o r a e r i a l i f a t a l l p o s s i b l e f o r i t w i l lp rove much more e ffic ien t than one indoors . Erec t i tas high as possible keeping the greatest proport ion ofi t hor izontal to the ground and keep the lead- in shortand as clear as possible of water-pipes, overhead mainscab les , te lephone l i nes , e tc .

Two aer ia l sockets provide al ternat ive moans of coupl ingt h e a e r i a l t o t h e a e r i a l c o i l . I n e f f e c t t h i s d o u b l e sthe range of the gain control , one socket posi t ion beingfor weak signals and the other for strong ones.

The clip on the earth lead should be attached to as goodan earth as possible.

The I2V. and 675V. batter ies are normal ly carr ied in thebattery box and the battery lead i3 permanently connectedto these. The plug has a keyway and this mist be correctly located before pressing i t home in the socket in ther e c e i v e r .DO NOT TEC TO FORCE THIS PLUG IN THE WRONG WAY ROUND.

IMPORTANT: I t is very advisable that the bat ter ies beremoved from the box if the set is to remainunused for any length of t ime.

Ext ra ba t te ry lead. Th is lead is p rov ided to enab le theuse o f ex te rna l ba t te r ies . The leads a re labe l led andmust be connected to the correct voltages.

IKFCRTAIJT: On no account oust the L.T. leads be connectedto a 2 -vo l t supp ly. Any vo l tage over 1 .5 i sdefin i t e l y no t t o be used . The H .T. vo l t agemust not be raised above 675- volts.

Battery l i fe. The receiver wil l continue to function with reducedsensitivity when the voltage at the H.T. batteryterminals has fallen to 1*8 volts and at "the L.T.battery terminals to 1.13 volts. L.T. consumptionis 125 mA.

Power, ^ The UK.3OIFP un i t i s fo r A .C . supp ly on ly. I t i sA. C.Mains designed to drop into the battery space and pick

up the normal battery connections. At one aide ofthis unit is an A.C. Power Line adjustment panelcovering 100-250 volt. To adjust the power unit forany line voltage two small countersunk head screwsare used and these should be screwed (a small driveris provided) into the two holes, the sum of whosecorresponding numbers moat nearly approximates tothe A.C. Power Line voltage. For example, if theLine voltage is 220, then one screw should beinserted in the hole numbered 200 and the otherinto that marked 20. See that the screws are firmlyin posit ion.

IMPORTANT: DO NOT CARET OUT ADJUSTMENTS WITH THEPOWER SOFFiy CONNECTED. It is advisablenever to plug into the supply unless theunit is properly located in the battery.box.

The L.T. supply in the A.C. Power Unit is smoothedand stabilised by means of a miniature accumulatorin float across it. It Is therefore essential whenswitching off both to unplug the power unit from thesupply and to switch off the set on the gain controlswitch, otherwise the cell will discharge into theset. If the accumulator cell becomes badly discharged a line hum will be heard in the receiverearphones when the set is in use. The cell may berestored by running the power supply unit pluggedinto the dnains with the receiver disconnected fora period of about two hours. This will charge theaccumulator at a heavy rate and for this reasonshould not be kept on for too long. For the samereason it is undesirable to have the set disconnected from the power unit or switched off when the unitis plugged into the A.C. Power Line except for thespecific purpose of recharging the accumulator. Thecircuit is arranged so that the accumulator is normallyoeing slowly charged all the time the set is in use,so that it should never become discharged by normaloperation.

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