Brimar data sheets show this triode pentode valve as designed for VHF frequency changer use. Mullard say that the ECF80 was designed for operation up to 220 MHz. This would be mainly for radio as television receivers tended to use the PCFnn 300 mA valves.

The triode is the oscillator and has to produce 5 V pk-pk signal. The screened pentode is the mixer. The valve has two cathodes so two independent valves are housed in the one envelope. The two valves can be used separately if required.

The thin glass tube envelope is 19 mm in diameter and, excluding the B9A base pins, is 47 mm tall.

 
Pin Connections

B9A	1	2	3	4	5	6	7	8	9
	a(t)	g1	g2	h	h	a	k-s-g3	k(t)	g(t)

 
Absolute Maximum Operating Conditions

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	6.3	0.43	250	180	-5.8	5.7	1.4	1.5M	2.1

Triode	Va	Vg	mAa	ra	gm
	100	-2	14	4K	5

Thanks to Frank Philipse for supplying the above datasheet

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This exhibit was last updated on 12 February 2008 {find valves by name}