Post by Paul OM0ET (Admin) on May 11, 2019 21:46:24 GMT
This 3th version of the QRP UltraLight MLA antenna has the same foldable construction designed for easy carry in a common laptop bag same as the 4th version. This antenna was designed primarily for 30m to 10m bands. Diameter of the main loop is 0,7m and same hight as the ver.4. I have used a wider PVC tubing of the foldable boom. All this changes caused higher efficiency on all bands, especially on 30 and 20M bands. Unfortunately by using the same variable capacitor I was not able to reach the 40M band. This band is included in the 4th version. Capacitor is connected in serial fashion because of very low resistance in a whole antenna circuit what is very important to secure a high Q and high efficiency of my loops. This serial connection causes lower capacitance of the capacitor and therefore the 40M band is missing in 3th version.
The tuning box is made of the solid ABS plastic. For SWR measuring I have used the QRP transceiver XIEGU X5105. The SWR on all bands is better than. 1:1.5
This ver. 3 MLA is working from 10MHz to 30MHz continuously and CB band is covered too. Total weight is only +/- 870 grams. No switch is needed. It's a QRP version for 5 to 20W (max. 10W CW / 20W SSB).
Please do not exceed the power limit of 20W! It may cause a fire on the capacitor plates or demage PA in your transceiver.
Dimensions:
Large loop diameter: approx. 70cm ( wire lenght is 2170 mm )
Small loop diameter: approx. 18,8cm ( wire lenght is 578 mm )
Capacitor: air type with 380pF+320pF (700pF) with small gearbox reduction - used as split stator type
Large loop is made of Nordix MWC 10/50 microwave coaxial cable (can be used RG213U but it's not hold the shape of ring as Nordix)
Small loop is made of 2,5mm copper wire PVC isolated
The boom is made of 3 pieces 20mm diameter PVC pipe
Total weight: 872g
Fishing tripod adapter:
I have made this new fishing tripods adapter. Is suitable for any standard fishing tripods. With this adapter is very easy to mount entire antenna on the tripod.
If you have some questions please write me down below
The tuning box is made of the solid ABS plastic. For SWR measuring I have used the QRP transceiver XIEGU X5105. The SWR on all bands is better than. 1:1.5
This ver. 3 MLA is working from 10MHz to 30MHz continuously and CB band is covered too. Total weight is only +/- 870 grams. No switch is needed. It's a QRP version for 5 to 20W (max. 10W CW / 20W SSB).
Please do not exceed the power limit of 20W! It may cause a fire on the capacitor plates or demage PA in your transceiver.
Dimensions:
Large loop diameter: approx. 70cm ( wire lenght is 2170 mm )
Small loop diameter: approx. 18,8cm ( wire lenght is 578 mm )
Capacitor: air type with 380pF+320pF (700pF) with small gearbox reduction - used as split stator type
Large loop is made of Nordix MWC 10/50 microwave coaxial cable (can be used RG213U but it's not hold the shape of ring as Nordix)
Small loop is made of 2,5mm copper wire PVC isolated
The boom is made of 3 pieces 20mm diameter PVC pipe
Total weight: 872g
Fishing tripod adapter:
I have made this new fishing tripods adapter. Is suitable for any standard fishing tripods. With this adapter is very easy to mount entire antenna on the tripod.
If you have some questions please write me down below