FM vintage control panels April 2, 2012 Koos Bouwknegt

Transcription

1 FM vintage control panels pril 2, 2012 Koos ouwknegt Schematic diagram and frequency coding for the R, R- and R-1. These FM liaison sets where used in the fifties and sixties for air to ground communication, mainly fitted in helicopters. ll had provisions for homing with appropriate antennas, and a pair of them could be used to retransmit communication. R : MHz, 8W RF 100kHz steps (280 channels) R : MHz, 10W RF khz steps (800 channels) SM-25 : MHz, 15W RF khz steps (880 channels) R1 : MHz 10W RF khz steps (920 channels) These FM sets had much in common. udio ll need an external audio amplifier for microphone and headset, usually combined with the aircraft intercom system. For the R-, this was the S-9, with provision for two headsets and three R- sets. The audio interface is 1Vpp, 1 ohm, both for input and output, so the sets could be cross-connected for retransmission. RTRN The R- needed two external relays for this RTRNsmit, but the control panels of the R- and R-1 integrate these functions in the mode selector switch. Homing ll sets have provisions for homing. In the R-, two vertical dipole antennas are fitted to the nose of the helicopter, and a motor driven, morse coded camwheel selects the left or right antenna. This produced either dah-dit-dit or dit-dit-dah in the headset, if the radio source was left or right in front of the helicopter. In the R- or R-1 system, a horizontal bar antenna was used on the roof front of the helicopter, in the form of a towel rack. ither the left or right end is connected to the receiver in a 100Hz rhythm. The result is presented on a cross-needle indicator I-, the vertical needle gave direction, the horizontal needle the signal strength. oth needles have an OFF flag, which are operated in parallel from the squelch output of the R or R-1 This document gives the coding tables of each panel for those who want to control the set by a P or other means. Note that the contacts should be rated for at least 1.2 / Vdc as they switch directly the electromagnetic clutches in the receiver-transmitter. The R- The RT-294 / R- had its control functions on 3 different panels. - S-7 To set the frequency; - S-4 Switch ssembly to select Homing mode, to disable the (carrier) squelch), and to select RTRNsmit if two sets and additional relays were fitted. - S-9 INTercom with the microphone and headset amplifiers. FM communication control panels 1

2 1. The R- The S-7 / R selects the frequency from MHz in 100kHz steps is a total of 280 channels. S-4 panel The RTRNsmit and Homing modes were selected on another control panel, the S-4 switch assembly. Here, also the squelch could be disabled and RTRN could be selected. MHz selector NN MM LL KK JJ P U Y Z HH ntenna Tuner (option) The circuit diagram of the S-7/R is straightforward. co-axial selector selects the full MHz in 28 steps (outer knob) and the 0.1MHz (10 steps) with the inner knob. The outer knob also sets the antenna tuner, although most R- systems had a wideband coupler that needed no tuning at all. Multiple panels S-7 can be connected in parallel. The one most recently set to LOL wins, and sets the others automatically to remote with a trip coil. 0.1MHz selector FF VOLUM lamps L M W K,N tripcoil X Remote local 27V, H, J 1V ON/OFF S-7 / R S T FM communication control panels 2

3 S-7 / R- frequency coding. 0.1 MHz coding S-7 / R Pin X X X HH X X X X FF X X X X X X X X X X X X X X X X X X From 24- MHz, From - MHz, Positions NOT marked X are connected to ground, the X lines are interconnected Pins on -pin connectors, both on S-7 and RT- 294/ R- ( same pins). MHz coding S-7 / R Pin X X X X X X X X NN X X X X X X X X MM X X X X X X X X LL X X X X X X X KK X X X X X X X JJ pin X X X X X NN X X X X X X MM X X X X X X LL X X X X X X X KK X X X X X X X JJ Pins on -pin connectors, both on S-7 and RT- 294/ R-. ntenna tuner coding pin X X X X X X X P X X X X X X X U X X X X X X X Y X X X X X X X Z FM communication control panels 3

4 2. The R- The R- and R-1 are similar, with the same mount, plugs and cable harness. oth systems have a -pole sub- connector on the receiver-transmitter, and a single, round -pole connector on the control panel. Signals and pinouts are identical, but the control panels can NOT be interchanged. For the circuit diagram see page 6 The RT-8 / R- has control panel - with squelch mode choice ( none-carriertone), volume, operating mode ( off-pushtotalkretransfer- homing) and two knobs to set the frequency. The left one has click positions for the MHz, the other 20 click stops for the 0.05MHz increments. Frequency is set from MHz in 800 channels at khz increments MHz coding, both R- and R X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X n X indicates that the line connects to ground in the control panel blank indicates that : the line is left open in the / R-1 : non X lines are interconnected in the - / R- MHz coding, / R- 69 X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X n X indicates that the line connects to ground in the control panel The remaining lines are interconnected in the - / R- Pin J is grounded from MHz Pin G is grounded from - 69 MHz Pin K is grounded below MHz (harmonics filter control) Pin h is grounded every odd MHz Pin i is grounded every even MHz ntenna tuner coding pin X X X X X X X X X X M X X X X X X X X X X L X X X X X X X X X X j X X X X X X X X X X z X X X X X X X X X X FM communication control panels 4

5 3. The R control panel for the RT-823/R1. This panel has the same -pole connector and functions as the - except for the MHz selector. The code in this selector is different to handle the wider frequency range MHz in khz steps (920 channels) The panel has 4 knobs for frequency setting, each with wafer switches. The MHz selection is a combined setting of two knobs, giving a lot of extra decks in the wafer switches. The MHz switch has 8 (double sided) decks! The 10MHz and 1MHz knobs are mechanically interlocked. With the 10MHz dial set to 70, the 1MHz knob range is limited to 5. If the 1 MHz knob is above 5, the 10MHz knob range is limited to a. The 0.05 MHz tuning of the is identical to the -/R- b. MHz coding X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X Pin J is grounded from 75 MHz Pin G is grounded from - MHz There is no odd /even output, nor an output to control the harmonics filter ( pins K,W, h, i, r are not connected) c. ntenna tuner coding ( identical to R) * pin X X X X X X X X X X M X X X X X X X X X X L X X X X X X X X X X j X X X X X X X X X X z X X X X X X X X X X The ambiguity lines J and G are also used in the antenna tuner. same code at 70,71,72,73 and 74 MHz settings. FM communication control panels 5

6 R- R-1 13 JJ OFF PTT RTRN HOM VOL 1 12 N y KK q -11 intercom amp PTT x d v PP c w u Second - or Receiving a signal IS TON RR Z Y V,r X W IS TON RR HH Retransmit interconnections Power Homing FLGS HOR VRT Harm.Filter mb mb Odd ven ,G F e f GG H,F FF t s I- MM NN K J G k m LL h i P R S T U 27k < MHz 1 MHz Select details on page 2 khz select Homing only Lamps H g M L j z a F G + 27V H J +27V ntenna tuner U 9 or U 9 Pins not used in - p. n, Pins not used in K,W, h, i, r, p,n, - / R / R -1 ontrol Panels Not in b kb FM communication control panels 6