The December 2012 VK3PF SOTA station

Colin (VK2JCC?) posted a comment asking about the station, so I decided to add this little item.

The Radio: Yaesu FT-817. Just a standard FT-817, so 5 W output. It has been “temporarily” removed from my microwave transverter rack, which also has a FT-817ND so that I can operate with 2 m or 70 cm IF frequencies with minimal operator errors when changing bands – the 2 m IF transverters go to a switch box then one FT-817 on 2 m, the other FT-817 is on 70 cm and is currentlt manual changed between the 2 trtansverters currently using a 70 cm IF. The FT-817 has had the SO-239 replaced by a type N socket.

Battery: I use an external 4S 5.0 AHr LiPo battery, which goes to a DC-DC switchmode downconvertor set for about 10.5 V output. I usually carry an extra battery as a spare. I hook a monitor alarm up to the LiPo to let me know when volts are getting down. On the trip over teh Xmas/New Year period, one battery was enough for all contacts from the start of the trip through to the Mt Granya activation, without any recharging. The alarm went off whilst I was chatting with VK1DI/3!

Mast: I use a 7 m heavy duty squid pole purchased from Haverford in Sydney. The local club (Eastern Zone ARC) purchased a box of 20 units, which worked out nice and cheap – about $35 per pole IIRC, the Club making a small amount at that price. Haverford offer a discount for a whole box, which more than covers the freight cost. Definitely a worthwhile buy if you or your club is interested in obtaining squid poles. Delivery was very rapid – only a couple of days.

Initially I used a 10 m squid pole, but the top 1.5 m is too flexible, so the maximum usable height is about 8.5 m. Then one day the pole snapped at the 8.5 m mark, so I decided to save mass and use the 7 m HD pole: the 10 m is 1.5 kg, whilst the 7 m HD is 1 kg. Every bit helps 🙂

Feedline: about 7.5 m of LL195 coax, BNC at the top and N male at the bottom end. The coax is a little stiff, but lightweight and low loss for its size. For a few trips I was using some RG316 teflon cable with SMA connectors at each end, but I noticed after a few trips that the shield was starting fray with all the rough handling, so switched to the LL195. I use 2 lengths of double-sided Velcro to coil the coax for transport, and then use them to hold the coax to the mast once on site.

Antenna: I normally use a homebrew 40/20 m link dipole, which in theory gives me 40/20 and 15 m. No balun used to date and no issues experienced with the QRP power level. I use a cut down dipole insulator from TET-Emtron.

I also have an alternate antenna system, which I used in November when I activated Mt Disappointment VK3/VC-014. It is a second 7 m HD pole which be used with the 40/20 link dipole, OR I can switch to 2 m to operate with a 6 element Yagi at 4 m above ground. Sections 5 & 6 of the pole have holes drilled to accept the 3.2 mm Al welding rod elements. I use 2 O rings and a poly pipe T piece as a mast to boom attachment, which slides over the book, with the bottom of the T sitting on the top of section 4 of the pole. I often pack both in the car and simply grab the pole & antenna combination that I intend using on that occasion.

Here is the kit, as per the Mt Disappointment trip (with the white RG316 cable):

VK3PF_Gear

The antenna is wound onto 2 cable winders from TET-Emtron – one for each half of the antenna plus some 3.5 mm cord tied to the far end of the dipole leg to string the ends out. The 2 m Yagi dipole and reflector need to be packed separate to the squid pole, but all the other elements can be packed inside the smallest pole section, making for easy storage. After this trip, I purchased and modified a fishing rod bag which accepts the squid pole, the driven and reflector elements and the poly T piece. The dipole plus some small tent pegs go into a nylon stuff sack. The FT-817 goes into another stuff sack, which has some cushioning made from closed cell foam to give the radio some protection. The 2 LiPos plus the regulator and the alarm go into a LiPo Guard bag.

I use an old JanSport back pack. The inner waterproof coating has had it, but I have not yet gone looking for a replacement. This pack is a narrow cut, allowing lots of free movement for the arms back and forward. It was purchased as a day pack for cross country skiing trips may years ago. Yes, it is still bright, colourwise, but it sits well and gives freedom of movement.

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