VHF experiment

[Werthers]

First off I just want to say that I've built a new dipole for 2 meters and up on the first test SWR is flat right across the band... I did no tuning or trimming of the elements what are the chances of that I got it accurate straight away by sheer fluke

I set it up in the living room just for testing purposes and did a quick range test on low power 6 watts and got a good signal report from another ham about 8 miles away so I know its working. I tried to see if I could see my signal on the websdr which is about 40'ish miles away but no signal showing on the water fall. Not really bothered as I'm just testing indoors.

I did another test on 4 meters with a homebrew 4 meter dipole with 4 watts but could not be heard at all even within 2 miles I was back of the box.

What I find interesting is that 2 meters seems to travel much further than 4 meters which is odd but then again these are indoor tests.

At least I know now that my 2 meter dipole is ready to go when I get a suitable pole to clamp it to so that it can go outside above the roof. I will also be adding a 70cms dipole to the mast as well.

[Tigersaw]

I would question how good the other guys 4m antenna is, you should cover 2 miles on whip even.
Presume dipoles will be vertical?
I thought you have said many times you cant put anything up.

[Werthers]

I would question how good the other guys 4m antenna is, you should cover 2 miles on whip even.
Presume dipoles will be vertical?
I thought you have said many times you cant put anything up.

I'm going to put up the VHF dipole and UHF dipole anyway and wait to see what happens its really the only way to do it even though I was told no in the past. I will just have to find a way to challenge it if and when I get told to take it down.

[Werthers]

I've been trying now for a couple days with experimenting with different configurations for a 4 meter antenna... its either ok or bad to worse but nothing satisfactory.

Here's what I've tried so far...

Inverted vee antenna - terrible, worked but range wise not good even when stuck out of a window on a pole and tried this in many configurations.

L antenna - better but still not good range wise.

1/2 wave dipole - slightly better but still not good range wise.

1/4 whip on a mag mount with foil as a ground plane in the loft better but still poor range

So even when the antennas were tested outside the window range was still poor. The 1/2 wave dipole would work theoretically if it up high enough with it being a somewhat larger antenna, I would never be able to have it as a permanent antenna anyway as I'm restricted to height and what I can get away with.

I've had permission from my landlord who said I can put up a "small" antenna 2 meters pretty much meeting that limit so for 2/70 I'll be able to have those outside but for 4 meters it will have to be an attic antenna.

Many people have given up with 4 meters so I'm not sure whether its worth the hassle so I've lined the attic floor with foil with a mag mount and 1/4 wave whip which is ok but not brilliant. I think I could get another 1/4 wave whip on the top but I will need to think of a way of making a impedance matching section to join it, and that should give me a bit more performance and with that I might just be able to make the trip for the 4 meter net but only just.

[mr_m3]

Some of the colinears you can get now do 6m/2m and 70cm. You may be able to find one that does 4m and a lot of them are below 2m in length.

Spraying the antenna black may help disguising it slightly

[Werthers]

What I've learnt from experimenting with 4 meters is that you really need the height/elevation for a 4 meter antenna to work decently and if there is to much in the way, such as buildings, hills etc the range will be crap. Its a tricky one because the same theory is the same with any band the higher the better, but 2 meters dose go further with less elevation. Its a bit like CB except 27MHz CB is better for range than 4 meters under normal conditions.

Its a confusing one and I know people will tell me 4 meters goes further than 2 meters because its lower in frequency and all that. Theory is never the same when you actually conduct the experiments. People from back in the day who used to run pirate radio stations would say its a watt per mile and this is true in some sense but based on many factors like height and terrain etc etc.

[Werthers]

Some of the colinears you can get now do 6m/2m and 70cm. You may be able to find one that does 4m and a lot of them are below 2m in length.

Spraying the antenna black may help disguising it slightly

Well I've been a bit naughty and just went for it and I haven't received any letters yet despite being told no in the past I just say sod them with everything that's going on in this country which I wont get into. I'm going to be cheeky and push my luck further with another antenna for 10/11 meters.

Just an update. The 70cms dipole wasn't that great performance wise but the two meter dipole works pretty nicely. I'll need something better for 70cms with some more gain for working simplex but nothing to directional so a collinear is in the pipe line to see if I can get a better chance of working simplex on 70cms.

The experiments continue for that ideal homebase VHF/UHF setup. I'm at a lose with 4 meters though.

I'm sorted for HF up to 14 MHz from 5 MHz and I'm almost there with 160/80 meters "Mag Loops for HF"