Radio and Light Signalling

Radio

Typically, the 'line-of-sight' distance between the launch-point and winch is ~1.2Km - low power radio should easily span this distance but close adjacency of the two antenna and an aluminium pole severely compromise the antennas and reduce the efficacy of any hand-held radio.

Previously, we used modified PYE (Taxi?) radios tuned to the 'BGA Common Airfield Frequency - 129.975MHz'. These were very complex to repair and there was some doubt that using this frequency for communication to the winch was appropriate.

Licence-free, hand-held PMR446 radios proved to have insufficient range to/from launch-point, caravan, retrieve vehicle and winch.

Around 2015, Business Radios and Licences were obtained. Fixed on Channel One (173.0625MHz) with no user (glider-pilot) ability to alter any parameters - even the power on/off button is disabled.

• 3x Hytera HYT TM-600 or TM-610 mobile radios:

1. Mounted in the launch point caravan.
2. On a slide mount for the winch (kept in parachute cupboard).
3. Spare (kept in parachute cupboard).

• 1x ICOM F3002 hand portable with BC-193 charger mounted in the caravan.
• 1x 8.33KHz spacing Yaesu FTA-250L Ultra Compact Airband Transceiver tuned to old 129.975MHz (common field frequency).
  New 8.33 channels for gliding are likely to be announced in late 2018.

Faults and Maintenance

2018: The winch radio was stuck on 'transmit'. No electronic fault found. The inadequate (1.6mm, 1/16") pivots were broken, probably due to operators pressing too hard on the lower end of the switch rather than 'thumbing' the upper end as intended. Pivot point replaced with a slug of 'hot glue' - working OK so far.

2018: During regular operation, the Winch Radio tripped the (10A?) CB. A reconditioned radio (with microphone) was purchased for ~£60. Geoff Grayer diagnosed and replaced the failed, reverse polarity protection diode.

2018: The Caravan radio microphone failed. One of the pivots was broken but it still does not transmit sound, only carrier. Diagnosis in hand as of 24Sep18 (Alan S).

September 2018: Transmitting on the Business Radio caused loud, annoying mush on the Airband Radio. Increasing the separation of the antenna fixed this but the new LED lamps switching regulators are causing a similar problem. The antenna must be separated from each other and from the aluminium mast as far as is practical.

Light Signalling

Despite previous problems, the last evolution of the 'Launch Point Caravan' achieved adequate light signalling from single 55W (35W?) 20° beam quartz halogen lamps with minimal effort to line-up the caravan with the winch. This was mostly due to adequate sizing of the cables and subsequent minimal voltage drop.

Faults and Maintenance

2017: The up-slack/all-out toggle switch tended to stick in the all-out state - maybe having exceeded its 10K operation lifetime?. Subsequent to replacement the automated panel would randomly switch to 'all-out' or 'stop' from 'up-slack' - I believe the switch may have been replaced yet again?

September:2018 I removed some 'extraneous equipment' and tested the unit in continuous 'up-slack' - after 30 minutes it went to a permanent 'all-out'! By disturbing the connecting wires on the board I was able to induce 'all-out', 'stop' and even inability to boot. The problems were in the negative (0V) circuit. Primarily, three wires into a single 'blue insulated' crimp were very poorly made and the 6.3mm terminal was very loose. I replaced this terminal with a stacked connector with two red crimps though this has strained the wire to the stop switch. Further testing revealed a fractured solder joint from the same switch which I re-soldered. After much disturbing of the board and wiring plus five hours of 'all-out' without a hiccup I believe this problem is resolved. Alan Saunders

2018 Launch-Point Caravan The 2018 caravan design has little consideration to correct wiring size. The lamps were running at ~10V (~60% of rated light output) and one bulb now had brown deposits, typical of end-of-life bulbs, especially those run at less than their rated voltage.

The 55W quartz-halogen lamps have been replaced by 2x 36W 30° LED lamps switched via the MOSFET relay as designed by Alan Sparrow. At ~6A the wiring and multiple terminals still dropped ~1V but these LED lamps maintain constant output from 10V to 30V. Winch drivers have found visibility of theses lamps to be more than adequate.

Unfortunately, the switching regulators in these lamps cause loud, annoying 'mush' on the airband radio.

Alan Saunders 04:24, 25 September 2018 (UTC)