The WATERS Q-MULTIPUER/NOTCH FILTER will permit you to tune out annoying heterodynes. It gives a null of ot least 40 db tunable across the entire IF passband*

The WATERS Q-MUITIPLIER/NOTCH FILTER combines on isolating amplifier and a tunable LC Bridged-T network with a Q Multiplier*

Designed specifically to fit the Collins 75S-1 or Collins KWM-2, the unit comes assembled ready for installation. Escutcheon plates and knobs ore matched to equipment so there is no discernable change in appearance of equipment.

Response of IF Passband for Various Positions of ■ Q-NI uili pie/Notch Filter

2 New Models Available:

337-S1A for Collins 75S-1 ..

340A for Collins KWM-2 & KWM-2A

Response of IF Passband for Various Positions of ■ Q-NI uili pie/Notch Filter

2 New Models Available:

337-S1A for Collins 75S-1 ..

340A for Collins KWM-2 & KWM-2A


Universal Hybrid Coupler iSee Sept. '62 Adv. in 731

Coaxrot Transfer Switch iSee Aug. '62 Adv. in 73)

Coaxial Selector Switch

Antenna System Transfer Switch (See Aug. '62 Adv. in 73)

Available at leading distributors Some territories avaifable for representation


also left off to show the components. This cover is made of perforated aluminum to allow air to be drawn up through the bottom, through the tube socket, around the tube and out through the exhaust fan in the rear, A few hoies were also drilled under the tank circuit to allow some air to fiow past the coil,

In the bottom view, a small enclosed box can be seen with a coax cablp coming from the side and a shaft coming from the front. This is the input pi network which is ganged to the output pi network bandswitch by means of a pair of pulleys and a bronze dial cord. (The pulley arrangement is shown in Fig, 1).

The ten adjusting screws seen on the pi net cover are the input and output trimmer capacitors for each of the five bands and are adjusted for minimum SWR at the center of each band.

Spring fingers along the partition which encloses the rf section assure good contact to the perforated metal cover. The use of exten sive shielding and by-passing of all leads entering the rf section minimizes TVI and reduces stray feedback from the plate to the grid^ thereby increasing the stability factor of the amplifier. It also prevents rf from getting into the power supplies which can cause loss of regulation, damage to rectifiers, etc.

Between the upper shield compartment and the front panel, are mounted the two Johnson turn counting dials for the vacuum capacitors used in the plate pi network. Also, in this space is a plastic disc which rotates behind a window in the front panel. On the disc are numbers which show through the window to indicate which band is in use. The shaft which turns this disc is an extension of the band change switch and extends through the front panel to the band change knob. On this same shaft is the pulley which drives the bandswitch on the cathode pi network circuit.

The rf amplifier section is housed in a brown hammer-tone desk top cabinet with perforated top arid rear covers. A square cutout was made in the rear cover to allow the muffin fan to protrude out of the back of the cabinet, A series of 2" holes were cut in the floor of the cabinet to allow air to enter the bottom of the chassis. On the rear chassis deck are the rf input and output connectors, the plate power supply connector, and the line cord.

When first placed into operation, the amplifier was found to parasite at about 120 mc. This could have been cured by placing a

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