Topic: Increase your 2902 range in ten minutes, at no cost

[WA4OPQ]

Here's an easy mod to increase the array-console range. It's merely straightening out the console antenna to increase it's efficiency.
I'll do some testing tomorrow to see how much of an improvement it is, but I'd guess 20% to 35%.

First, make sure you have the right tools, specifically a small diameter jeweler's screwdriver for phillips. The lower two screws have a small diameter access shaft. If you can't unscrew these screws Amazon is your friend.

To start remove the batteries, all five screws and break the case open with your fingernails.

Picture 1: [ You are not allowed to view attachments ]
See how the red antenna wire on the right is curved over? A required mechanical compromise for a poor RF design element. You can also see where I have drilled the hole. I started with a 1/16" drill and then used a 5/64"
Picture 2: [ You are not allowed to view attachments ]
The antenna now routed through the hole. If I did it again I would drill the hole a bit further to the right.
Picture 3: [ You are not allowed to view attachments ]
How the console looks with the completed mod.

My example is a WS-1900, but it's just a 2902 with the WiFi removed. Otherwise identical.

[WA4OPQ]

I moved my array 40 feet further away, to a location that didn't work before. It's receiving fine on the console.
I'm pleased.

[the beteljuice]

Seems to be plenty of space in the case, why not just double the length ? - of course you can still add a little bit on externally.

Remember the little transistor radio telescopic aerials ...

[WA4OPQ]

Seems to be plenty of space in the case, why not just double the length ?

At 915 MHz the optimum length is 78mm, 3.07"

[CW2274]

Seems to be plenty of space in the case, why not just double the length ?

If I recall back in my CB days, this is the way to go as it's a more efficient wavelength of antenna (i.e. making a 1/4 wave to a 1/2 wave).

[WA4OPQ]

An external center-fed half-wave antenna would be more efficient, but it's no longer a ten minute project.

[Bushman]

Seems to be plenty of space in the case, why not just double the length ?

At 915 MHz the optimum length is 78mm, 3.07"

At quarter wave.

[galfert]

You could probably create a dipole by soldering on another equal length antenna wire to the ground point closest to the antenna point and have it point in the opposite direction (down). A dipole antenna increases the gain.

I can't tell from the pictures but is the black wire possibly already there acting as the dipole?

[WA4OPQ]

The red wire is a 1/4 wave antenna using the circuit board as a ground plane, similar to an antenna sticking up in the center of the roof of a car.
A 1/2 wave dipole is fed at the center, so it would involve running small coax from the circuit board out to the insulated center of a 6.14" piece of wire.

I chose the simplest solution. If I still needed more gain I'd add a yagi to the array. Which I may still do.

[WSWeather]

Did this change the rssi indication ("number of bars") on the console?

[WA4OPQ]

Did this change the rssi indication ("number of bars") on the console?

It went from 3-4 bars to 5.

[DaleReid]

Is the transmitter vertically or horizontally polarized?

[WA4OPQ]

Is the transmitter vertically or horizontally polarized?

The antenna in the array is vertically polarized.  It's been helically shortened.