Monthly Archives: April 2014

Using Petroleum Jelly for temporary antenna connectors

I’ve been trying to find a product to protect my temporary antenna connectors for either Field Days or my holidays near the sea. The problem is two-fold; firstly water ingress to the coax and the connectors from rain and secondly corrosion. The corrosion issue only seems to occur near salt water and spray and occurs within a couple of days.

petroleum-jellyI used to use self-amalgamating tape for Field Days but the effort in applying and removing it forced me to rethink. I started using high quality insulation tape instead – the stuff that has some nice stretch and doesn’t go brittle in the cold. This worked for many years. Unfortunately, the cheap stuff, from say Maplins might have the required insulation properties but has a brittle plastic feel and not very pliable – it’s certainly difficult to make waterproof between layers. Last time out for Wythall Radio Club SSB Field Day, torrential rain found its way through a crack between two layers of tape and the SWR went high.

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TS990s External Keypad

I recently had the privilege of dealing with Chris Taylor of Taylor Made RF who supplied me his rather excellent custom keypad for the Kenwood TS990s.

Chris gives the device the part number TMRF TS990KP and it follows the convention as outlined in the user guide 16-7 of the TS990s user manual which allows for the user to program each of the 8 function keys a specific task, for instance; change antenna, play a recorded voice macro or change filters. An extremely handy accessory.

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Of course, you could build one of these but for an “appliance” operator and for sheer mini-bling, the TMRF TS990KP is a delight to use. It comes very nicely packaged with basic instructions, a simple 3.5mm jack to jack stereo lead and of course, the engineered keypad.

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How to make a stealth amateur radio wire antenna

Until recently, I had a) a 40m triangular loop in the back garden which I called a “micro-mega-loop” and b) a 60m loaded loop that allowed me to get on 80m. The two loops looked a bit horrendous not only because of the wire in the air, but because I used halyards to lift them in the air to the top of wooden stair rails. It was all very messy. They were also extremely close together along the back of the garden which meant some of my RF was absorbed by the other loop. See here: http://www.m0mcx.co.uk/sg-230-feeding-60m-skyloop-deltaloop/

DSC_0217I like loops for two reasons, a) for my small garden plot, I can achieve in half the size, what other do with a full size dipole and b) a resonant loop will also resonate on every harmonic, that means tuning a 40m loop at 7.1 Mhz means I also get 14.2, 12.3 and 28.4 Mhz.

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