FT240-43 Torriod based on the W1JR design
£60.00
Email for availability
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Balun With Out Mounting Kit £60.00 |
Balun With Mounting Kit £75 |
FT240-43 Torriod based on the W1JR design
This form of choke is referred to as an Inline-Isolation Balun. Design is quite simple. 70cm of RG-303 high power coax coiled 8 times round a FT240-43 Toroid housed in a waterproof box and potted with Polyester resin. Termination is a chassis-mount SO-239 on opposite ends of the box.
Balun is tested with full UK power limit due to power restrictions; under perfect 1:1 SWR conditions the FT-240 can handle 1KW of power.
In-line Isolation Balun consists of
- 10cm x 10cm x 5cm UV resistant Box
- 1 x FT240-43 Torriod core
- RG-303 high power Teflon Coax or similar
- 2 x SO-239 Chassis Mounted Sockets
- All fixing hardware stainless steel
- Potted for 100% WX proofing
- Feed at lowest band, E.G. 20m
Make your own balun
1:1 Balun Options
Steve G3TXQ has done a lot of research on the use of different types of cores and air cored ferrites, the results can be seen on the chart below. For a link direct to his page please click here
The two types I refer to within this site are the 8T RG58 on FT240-43 but substituting the RG58 for RG142. Also the 6 x FB-31-1020 on RG213. There are many other ways listed on Steve's list below and more info can be found on his site.
http://www.karinya.net/g3txq/chokes/
