19-Set Leads, Aerial No. 2

[David Dunlop]

This is another bit of 19-Set kit that has proved difficult to find in this neck of the woods over the years. It serves the same purpose, and probably has the same Pye connectors, as the Connectors, Co-Axial No. 11A but I think it is much shorter. Can anyone advise the length of it?

David

[marco]

David,

Aerial feeder No.2.
The lenght from the cable is 8,75 inches.

Marco

[Mike Kelly]

Hi

Ive been told the B set coax cables are a TUNED length . The correct length is for matching the impedance , could be a muliple of 1/4 wave length ?

Mike

[universalgrl]

The 20" "B" set aerial is a half-wave end fed vertical rod connected to the 19 set panel by means of a special, tuned length co-axial feeder. Only 2 standard length were made 42" and 84" and must on no account be shortened.
So says EMER FZ 253/2 Jan 1945.

[David Dunlop]

Marco. Thanks for posting the images.

Mike and Roberta. Yes indeed, that B-Set aerial setup is extremely length sensitive. I remember finding a large number of the smaller 'Leads' in NOS status at a local shop many years back. Each was still coiled up with a set of factory cords holding them together, and each had been chopped in half by some sod before being disposed of. IIRC there was a small metal tag on each cable stating they should not be cut/shortened. Sadly I was dumb enough then not to pick them up anyway for the connectors and tags.

Interesting there were only two versions, but on thinking, it does simplify things. The shorter 'Leads' appears to be referenced on all combat vehicle installations. The longer 'Connectors No. 11A' shows up in the Installation Instructions for the 15-Cwt series Wireless Trucks and the 30-Cwt Command vehicles. In these, there is quite a distance from where the wireless set tables are, up and along to the Aerial Chimneys on the roof.

Hopefully, if these items hit eBay, the venders take time to ID them properly, and not just as 'cables' or some other vague name.

David

[Chris Suslowicz]

The three feeder cables are:

ZA.3141 Leads, Aerial, No.1 for the "A" set to the variometer.
ZA.3142 Leads, Aerial, No.2 for the "B" set to Aerial Base No.9 (standard length)
ZA.3143 Leads, Aerial, No.3 for the "B" set to Aerial Base No.9 (extended length)

The No.1 has elbow sockets on each end and the length is not critical. It was frequently shortened by the wireless fitters to suit the actual installation. (Later on a variety of different lengths were standardised, for specific installations.)

The No.2 and No.3 leads were specific lengths to match the 'B' set to the Aerial Base No.9 plus Aerial Rod 'G', and were marked (as noted elsewhere) "Tuned Length - Do Not Cut". They had an elbow socket for the set end and an in-line socket for the aerial base (this required a "horseshoe shaped" wire clip instead of the straight bar variety used with the elbow connectors, but a lot of replacement No.9 bases were shipped with the wrong clip because "standard" Pye connectors were used, and the clips had to be changed before installation).

These were redesignated, becoming Connector, Coaxial, No.10 (from Leads, Aerial, No.1),
Connector, Coaxial, No.11 and No.11A for numbers 2 & 3, respectively.

Connector, Coaxial, No.10A was used between the WS19 and the RF Amplifier No.2 in a "side by side" configuration, while No.10B was used where the RF Amplifier was mounted on top of the set. No.10E was used to connect the RF amplifier output to the Aerial Tuning Inductance No.1 when this was mounted on the WS19 supply unit top, or for the set to variometer when that was fitted to a top plate on the WS19. The 10x range went up to "K", at least, but there's no particular pattern between the suffix letter and the length.

Later still, they dropped the suffix letter and used "Connector, Coaxial, No.10" followed by the length (in inches), e.g. "16-in."

Eventually some of these acquired NATO Stock Numbers.

Chris.