Simple Wire Vertical Question

[KA1OWC]

Hi: I am putting together a very simple single wire vertical antenna for 20M...I will be using an expanding 20ft fishing pole to support the wire...(About 17 feet)...Now, here's the question: It is a single wire; It will only be for one band; It will be used solely for JT-65 and maybe other digital modes later on; QRP only (5-10 Watts)...I plan to feed it to the house with coax...Now: Do I need any sort of balun or un-un connected to the single wire? Should I run the antenna wire to a center coax conductor and the braid of the coax go ground if I don't need a balun/un-un? If I need to use a balun/un-un, would the attached pictured unit be good enough and just how would I connect a single wire to it? Sorry for the long question, but I am just starting our with digital and really need the help! Thanks a lot,

Steve KA1OWC

[PA5COR]

17 feet is a 1/4 wave for 20, put down some radials and it will be close to 50 Ohms anyway, the perfect 1/4 wave with perfect ground plane is about 36 Ohms, but with a few radials which isn't perfect the situation will be close enough for 50 Ohm.
Keeping the coax on the ground or better 2 inchees under the ground will keep r.f. off the coax and wwith a bitty tuner you get a good working antenna, for a mono band.
You can set the SWR also with varying the length of the radiating wire, so that a tuner is not needed.
Directly feeding it with coax, as i do with my verticals here.

[KA1OWC]

Regarding the coax: center conductor to the radiating wire; what do I do with the braid of the coax? Thanks for the help!

[PA5COR]

Connect the outer braid waterproof ( all connections) with the radials, you can drive an ground stake on which you connect all wires and braid.
I mostly use an chassis part and PL259 connector so i can disconnect it quickly in case of thunderstorms passing over.
Do make the coax connections waterproof, braid with capillary working will suck up water quickly and make the coax unusable in short time.

Radials should have about the same length as the radiating wire, it does not matter if you put them on the ground or bury them a few inches, the ground will detune them anyway.
Bare wire, isolated wire doesn't matter as well.
Just as much as you can put up, and where you can put them in the plot, even shorter ones will do if the space is short.
For my 160 meter vertical i have 3000 feet on my plot, put in everywhere i could get them varying in length of 200 feet to as small as 30 feet, covering as much ground as possible.
Put a 5 watt carbon composite 100K Ohm resistor from the radiator to ground, to direct static to ground, if you use an 100 watt transmitter an spark plug from an car can be used as lightning arrestor, for me that works up to 1000 watts.
In case of lightning it will form a spark, that leads most charge to ground.