Can it be done, - yes...
Will it work well - maybe!
You are going to have mutual coupling between the loops messing up
resonance and impedence... You cannot just cut the loops per the
formula and nest them inside of each other, connected at the feed
point, and still be resonant... That is your first problem... Search
the literature on triband quad loop beams and their results will point
the way to the appropriate modification of the usual loop formula...
Next, your impedences will drop and 100 ohms is not likely to be the
number...
For a single feedline try a quarter wave of twin lead from the mutual
feed point to each respective loop... Personally, I would use relays
to cut out the unused loops and save myself a lot of cut and try...
ymmv...
15 -17 will talk to each other... Try hanging them at right angles...

denny / k8do



John wrote:
I have been researching for a while now around the area of nested delta
loops. I want to upgrade my multi-band vertical antenna with delta loops,
each one resonant to cover 20 to 10m. However there is nothing on the
internet about nested delta loops. My wish is to have the delta loops
orientated such that they are pointed at the top and fed one third of the
way up one of the vertical sides to get a low angle of radiation.

I realise that they have an impedance of around 100 Ohms and this would need
to be matched. The usual method of doing this is to use a quarter wave
length of 75R coax to match to 50R.

Much in the same way that parallel dipoles can be fed with a common feeder,
can 5 delta loops be fed via coax matching stubs with a common 50R feeder?
(i.e. bring the ends of the matching stubs together?).

I tried in the summer to nest 5 delta loops with the feed point as described
above and then brought the feed points together (without matching stubs) ,
however it is not physically possible to do this - they really need
separating out.

Any ideas any one? My basic aim is to have 5 resonant antennas with no
tuning unit involved.

Thanks

John