I’m so happy with the results of the Fritzel MFB-13 that I decided to put it on a rotator so I can swing it around from the shack. I had an old Daiwa DR-7600 lying around with DC7011 controller so I spend the afternoon installing that. I also put up my MasPro WN59N 2m/70cm combi yagi (not connected yet) in case I want to do some USB on VHF/UHF in future.

I tried to model the MFB-13 in MMANA and calculated the loss. On 10m it’s about 0.1 dB (it’s a full size dipole with the ends folded back about 40cm, on 15m it’s about 0.3 dB (not sure if that’s correct), on 20m it’s about 3 dB (half of an S-point). I’m probably going to use it on 10m/15m mostly because I didn’t have an antenna yet for those bands. 20m works fine on my EFHW as well so I have a choice now.

Pretty cool set up right now don’t you think?

73 Pleun

I just put up a Fritzel MFB-13, it was generously donated to me by PD9RD. The MFB-13 is a folded back rotary dipole for 10m/15m/20m. The width is only around 2 x 2.1 meters (so total length around 4.2 meters). It’s got a “double” (10m/15m) trap in both elements, while the element length is not even a quarter wave for 10m it’s a compromise on all bands but I’m hoping the directional effect and the height will compensate for that.

The SWR is very acceptable on all bands. Lowest SWR is a bit low on 10m and 15m but way below better than 1:1.5 on the entire band. I’ve tuned the end rods for 20m to have the lowest SWR in the middle of the band and despite of the two traps acting as loading coild on 20m the SWR is better than 1:2 on the entire band and seems to work fine on 14 MHz as well.

I haven’t put it on a rotator yet, it’s now pointing in NE / SW direction and I’ve let WSPR with 1W band hopping 20/15/10 since yesterday afternoon and, results are not bad at all:

Maybe this afternoon I will turn it in N/S direction to see if the picture looks very different.

73 Pleun