Comet H-422 40/20/15/10M Trapped Dipole Antenna + 80 meters band
Antenna Comet H-422. I have my Comet H-422 in a V configuration on a 10m Spiderbeam mast on the second floor balcony.
Performance on 40 meters is great, works much better than my 40' vertical. On the higher bands, it's great.
Is it possible to use H-422 on 80 meters band? Of course the size too small for that band, just 0.125 wavelength.
This is prototype of 5 bands antenna system. Dipole Comet H-422 and some extra parts, two inductors and switcher on the top of mast. On high-frequency bands coaxial cable is connected to the dipole, on 80 meters disconnected.
Inductors connected between the dipole arms, and the mast. The dipole arm is connected with the inductance with the mast, and coil tuned to the desired frequency of 80 meters.
Screen-shot of the SARK-110 Antenna Analyser. Without antenna tuner MFJ-926, frequency is 3530 kHz. SWR meter of Yaesu Ft-1000 shows 1:1, but SARK-110 shows three resonance frequencies.
Two resonances close to 3530 kHz- resonances of dipole arms with coils. SWR on desired frequencies is 1:1. We don't need to use antenna tuner. The resonance close to 5 MHz - resonance of mast plus radials. On 80 meters band antenna works excellent.
Skimmers of east cost show good level of signal. Transceiver FT1000D, output power 150W.
The inductance is connected in parallel to the dipoles.Separate wire from the middle of the inductance 2x16 uH to the ATU at the base of the antenna.
Two reed relays are housed in a balloon housing. In the ranges of 40m to 10m, the relays connect the cable to the dipole. On the 80m band the cable is disconnected and the antenna works as a vertical. Load - dipole arms connected via 16uH inductance to the vertical part of the antenna.
Previously, when adjusting the dipole arms to an 80 meter band by changing the inductance - the antenna worked very effectively. The tuner is designed and tested to replace the inductance and allow you to adjust the dipole arms in the 80 meter band.
© V.Dmitriyev 2018