I have added both the 60m and 80m extensions to the system
The 60 meter extension is particularly suited to the narrow allocation on 60m between 5.3 MHz and 5.4 MHz. The SWR is at or below 1.5:1 for the entire 60m allocation. See the image below:
Weight of the entire antenna is 316g with the 60m extension - or only 53g heavier than the base antenna with 40-6m coverage.
Testing of the antenna using the Reverse Beacon Network on December 26, 2020 showed that the second harmonic of the 40m half wave has a better signal than the third harmonic of the 80 half wave as seen on the 20m RBN hits at 1527 UTC on 14.061 MHz (third harmonic) versus the ones at a later time on14.065 and 14.067 MHz (second harmonic). RBN S/N ratio on both the 60m and 80m extensions were quite good and comparable to the 20m S/N ratio. One can easily be heard on the 60m and 80m extensions.
The band width on 80m is quite narrow - with the 2:1 SWR band width being about 100 kHz wide and the extension must be carefully tuned for the rig to be employed. If you are a recent buyer of the LNR MTR4Bv2 or the YouKits 7 Band 2020 version (https://www.youkits.com/products/youkits-hb-1b-mk5-2020-4-band-qrp-cw-transceiver-fully-assembled-and-tested), these extensions would be perfect.
Contrast the above image with the full size 135 foot EFHW Inverted L shown by the image below - shows that the shortening of the antenna has reduced the bandwidth by a factor of 3. The KX3 being my shack radio has no problem tuning the antenna in the upper portion of 75m in the phone portion
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