Weatherproofing indoor antenna for Outdoors

Hi - I’m new to antenna’s but I’ve got a question about outdoor antennas. I’ve got an indoor antenna that works well with my gateway from my 2nd floor window but would like to see if I can improve it by installing it to my TV/Satellite mast that is installed on very tip of my house.

Rather than buying a new outdoor antenna and run the risk of getting a poor performing one (I don’t have the equipment to test antennas and I wouldn’t know where to start!) I wonder if it’s possible to weatherproof my indoor one? I’ve been trying to find out what the core differences are between indoor and outdoor ones, and so far the only things I can find are that Outdoor ones usually use N connectors (but not always) and are usually encased in fiberglass tubes.

If I took my indoor stick antenna, put it inside a fiber glass or PVC tubing (is there a difference to radio blocking??) and then I was going to wrap the connectors and tube endings in combination of electric tape and then amalgamation tape to seal it.
Would this work at all?

If you put an antenna e.g. a dipole that is resonant into a plastic tube, the antenna will be detuned. This is because of the capacitive effect of the dielectricum “plastic” being in the reactive near-field of the antenna. The resonance frequency will decrease.
You need an antenna-analyser to observe this effect.
I would recommend to buy an outdoor-antenna with not too much gain (3 dBi is sufficient) that is appropriate for your frequencies.

Hi Wolfgang - many thanks for the reply. I might have to bite the bullet and look at getting an antenna analyser. I’ve just found a nanoVNA for about £60 - hoping that that might give me a better idea of how well an antenna may do. Are these any good to get a reasonably rough idea of how well it performs?

The VNA will tell you if the antenna is well matched, in that you will know how much of the transmitted power is being radiated.

And VNAs are very useful tools for basic checking of antennas.

However, how well the antenna performs in reality depends on where exactly the radiated power is going and the VNA cannot tell you that only practical experiments can.

I fully agree with LoRaTracker. In addition it makes sense to learn a little bit about antennas and what the values shown by a VNA or an Antenna Analyser mean.
E.G. resonance and matching are different things.
Have fun!