I'm trying to get into backpacking QRP, which has lead me to read up on various ways to construct very portable wire antennas. I would ideally like to have a single antenna for the CW parts of the 40, 30 and 20 m bands, while avoiding having to bring a general purpose tuner.
There are various options, but one that caught my eye and which I want this question to be about is the use of crocodile clips to simply disconnect parts of the wire. Using my current needs as an example, an end fed wire around 20 meter long could thus work as half wave on 40 m and as a full wave on 20 m, and if I want to work 30 m I just disconnect 5 meter at the end to get a half wave once again. Perhaps I could even put a pair of clips in the middle as well if I want a half wave antenna for 10 m as well(?) I don't want to get the question too stuck on this precise design though, but keep the focus on the technique itself.
My main question is: Are there any downsides to using crocodile clips to change the length of the antenna? (or even to change its topology?) Is there anything special I need to keep in mind if I go with this approach?
I could see how this could be less appropriate if you plan to transmit several hundred Watts, but I'm thinking QRP.
I imagine it might be hard to get the connection good enough in terms of resistance. Also, the resistance of the clips themselves, being different from the wire, might be a problem. I've tried using a search engine, but it's hard to separate pages where crocodile clips are discussed from those where they are simply used in experiments.