Complete 1:9 UnUn DIY kit for long wire antennas.
1:9 UnUn 600 Watt DIY kit 1.8 – 30 MHz, with proper strain relief. This 1:9 UnUn is built around an FT240-43 ferrite ring core. Around this ring core an impedance transformer with a ratio of 1:9 is built up. Now with handy attachment plate to be able to attach the ring core, this means gluing is no longer necessary.
The long-wire antenna has the advantage that when using the right length wire, it can be used on many HF bands. This means that the antenna on many HF bands shows a reasonable SWR and often the internal tuner of the transceiver is sufficient.
A long-wire antenna requires a countercapacity. This can be resolved in several ways:
- Use the power line coax cable as a countercapacity (high risk of interference problems)
- Use an earth pen or earth net as countercapacity
- Use one or more pieces of random wire length as countercapacity
The 1:9 UnUn is wrongly called a 1:9 BalUn in many sources. In my opinion, this is incorrect because there is no transformation to a balanced antenna system.
TIP: With a 1:9 UnUn and long wire antenna always use a common mode choke. The main reason to use a common mode current filter is to ensure that the coax cable does not become part of the antenna system and therefore starts to radiate unwanted. This has all sorts of nasty effects, think of: interference, EMI, RFI disrupted radiation pattern of the antenna, restless noise level. This last point is because not only does the coax cable’s shield radiate when you transmit, but the shield also works as a receiving antenna. You can link the common mode choke directly to the 1:9 UnUn with a PL-male-male connector or leave some distance. This piece of coax cable between the 1:9 UnUn and the common mode filter then serves as a countercapacity.
1:9 UnUn 600 Watt Parts
This kit includes:
- IP65 enclosure 100x100x55 mm
- Toroid Amidon FT240-43
- Winding wire 1.25 mm – 1.8 mtr. – enamelled copper wire
- PL 259 Chassis
- Toroid mounting plate
- 4x Stainless steel M3 6 mm screws
- 4x stainless steel M3 washer
- M3 Cable lug
- M5 Cable Shoe
- Stainless steel (A4) M6 strain relief
- Stainless Steel M6 Nut
- Stainless Steel M6 washer
- Stainless steel M6 Spring washer
- 2x Stainless Steel M5 Bolt 25mm
- 2x stainless steel M5 wing nut
- 4x Stainless Steel M5 Nut
- 4x Stainless steel M5 washer
- 4x stainless steel M5 spring ring
- 4x stainless steel M5 toothed washer
- 4x stainless steel M3 Bolt 12mm
- 4x Stainless Steel M3 Nut
- 4x Stainless steel M3 washer
- 4x stainless steel M3 toothed washer