To solve that problem, I’ve constructed some antennas. The most effective one so far is one I can place outside my rented house based on simply cutting 1/4 wavelength of casing, shielding, and dielectric away from one end of a long run of 75ohm RG6U TV coax. Of course, if I don’t want to lose all the signal in reflections between the radio and the antenna from the impedance mismatch, I had to find out how to match the radio’s 50ohm impedance with the cable’s 75 ohm impedance.
I overcame that obstacle, anecdotally at least, using the technique of cutting the coax so that it is approximately 1/2 wavelength multiples of the frequency I want to operate on. To be clear, that means the length of my coax was some multiple of 1/2 wavelengths + 1/4 wavelength. I learned about this technique from http://www.jpole-antenna.com/2015/01/28/using-rg-59-or-rg-6-catv-cable-with-an-amateur-radio-antenna/
This made it so that when I removed the top 1/4 wave of shielding to form the antenna I had a multiple of 1/2 wavelengths of cable remaining. I thought this was kinda cool since I got out of needing any hardware to connect the antenna to the transmission line.
Of course, you need a way to connect the male F connector of the CATV cable to the BNC connector of the average 2M transceiver. I splurged on that at my not-so-local RadioShack in Ellsworth, Maine. There they had a pretty cool old-school selection of electronics DIY components — I was amazed. Anyway, I spent about $6 on an Female F <-> Male BNC and I was in business! Here is the antenna on a piece of copper pipe with an old light fixture base as a reflector/ground plane that I later placed up off the ground a little temporarily:
At a later date I’ll do some testing to see how well this antenna works. SWR and field strength measurements anyone? I think I’d like to call my new antenna a “C-Pole” for Cheap-Pole. Making a terrible play on the “J-Pole” name 🙂