HF D/F Outfit RH2.

  Throughout the pages dealing with transmitters and receivers, we have mentioned the 'mix-and-match' approach of using specific pieces of equipment to form a system. Thus, a tuner amplifier B36 for example, might appear as the main receiver in several different systems whether D/F, intercept {RCM} or general communication.

  The RH2 HF D/F Outfit is no exception and employs two receivers [both of which you will have met on the receiver matrix] namely the B28 and the B36. BUT, you will say, I found no evidence of a B36, and you would be right! To compound the difficulties of keeping track of equipments which in one application could be 'stand alone' whilst in others 'a part of a system', individual equipments could change names, and did, frequently. The B36, used for RH2, is in fact a very slightly modified [but exact look alike] B21B which is used for the Outfit FH3 - confusing? - YOU BET ! (Incidentally, and this is the only page on the whole site on which we will say this, if we were to add every combination of every piece of kit notwithstanding the subject matter (receivers, aerials, test sets etc) we would not only confuse you further, but add many tens of scuttles to our various matrixes.)

  So what was the Outfit RH2 ? The navy had always used HF/MF D/F stations with a variety of aerials, some fixed and some rotating in both afloat and shore station fits. The shore station fit, invariably a Naval Air Station {RNAS} had fixed aerial system manifest in the Outfit AH6 [shown on the matrix] sited in an advantageous area of the airfield. The airfield also had its own mobiles. These vehicles were fitted out with radar or communication equipments and could be moved around as required to enhance the main station fits. This fleet of mobiles had D/F vehicles and one such was the Royal Naval W/T Van No 21, which was used extensively during WW2.

  Built into the roof of the vehicle was a large ROTATING {manual, not powered} spaced loop aerial system consisting of two parallel screened loops, connected in opposition. A vertical open aerial , terminated at the lower end by a counterpoise, is used in connection with the loops, joined in parallel for sense determination. For non-directional reception a separate search aerial is provided. The outfit covers a frequency range of 2 to 20 Mc/s and should give correct bearings not only on a ground wave but also on a sky wave.

  This file RH2 Aerial System gives details of the RH2 Aerial System.

  The system D/F receiver was the B36, but a B28 was assigned as the search receiver looking for the signal to be D/F'ed. This file Overal Wiring shows the complete wiring for the D/F system but omits the B28 search receiver.

  This is what the bearing indicator looked like. Note that from the Aerial System file above, that this unit is just above the hand wheel Bearing Indicator This is the typical directive characteristics Directive Characteristics. Finally, a picture of the D/F receiver, the B36.....or is it a B21 or perhaps a B23/B23A