NCE Radio Tips

By Don Fiehmann

Don's Test Report for NCE High Gain Antenna
NCE Radio Users Guide
Review of the New NCE Radio Base Station and Repeater

Thanks to Don Fiehmann for documenting his efforts to extend the performance for NCE radio!

BATTERY LIFE IMPROVEMENT

My layout was not used for over a month due to back surgery. When I did get back to running the layout
I found that the batteries were depleted in both of my wireless cabs. They were both OK before the surgery. My reasoning as to why this happened was that there was some leakage in the circuits that drained the batteries. To verify my theory I put in two new batteries (3volts) in my Pro-Cab and then measured the current by connecting a meter to the terminals of the other two batteries that were not installed. I measured 0.15 milliamps(150 microamps). While this is not much current, it is draining the batteries 24 hours a day 7 days a week.

Rechargeable AAA Ni-cad batteries have 180 mAh (milliamp-hour) available. The leakage current would drain these cells in less than two months even if the cab is never turned on. I check the leakage current on my wireless Cab-04 with the two batteries installed and found that the “off” leakage current was about the same as the Pro-Cab. My solution was to install a small slide switch in the back of both cabs that was connected in series with the red wire from the batteries. The switch opened the circuit so no current would flow. Before using either of the cabs I simply turn the switch on. When finished using the cabs the switch is turned off until I use it the next time. Normally I turn it on at the start of the evening secession and off when I shut the layout down for the night. The switches I used were from Radio Shack. They were a SPDT Submini Slide Switch with a 3 amp rating (RS 275-409). Note that the RS catalog listed this number with a different description . There are a few more in the RS catalog that would also work OK. A package of two of these switches is under $2. This is about the cost of one battery for each switch.

Three small holes were need in the backs to mount the switches. I used a pin vise and a small file to make the holes. The switch was attached with a couple of short 2-56 screws and nuts. Then the red wire to the batteries was cut and the two ends soldered to the switch. Be sure to use the center lug and the lug near the top of the cab for the two wires. This way up is on and down is off. The switch handle is small enough that it barely sticks above the plastic back. This makes it hard to accidentally switch the setting, but easy to switch with a finger nail.

Arrows show location of Submini slide switches.

Cab open shows switch. Be sure that the switch does not touch internal metal part in the cab.

CHOICE OF BATTERIES

Choice of batteries are one-time use like alkaline batteries, rechargeable like Ni-cads and the newer Nickel-Metal Hydride batteries. Rechargeable cells would seem to be the way to go, but, there are some problems when you use these. They both have a self-discharge that will have them dead after while even when they are off and not used. Nickel-Metal Hydrides have high capacity, but also a high self-discharge rate. I use this type in my digital camera it they are fine, leave it set for a month or so and I need to recharge the batteries. Nicads also self-discharge, but not as fast as the Nickel-Metal Hydrides. Ni-cads also do not like to be in a string of cells when they get low and the power is turned on. The problem here is that as a cell become discharged there is a possibility that one or more of the other cells will continue to put out voltage and cause the discharged cell to become reverse biased. Ni-cads do not like this condition and can cause the cell to fail. Rayovac makes a Renewal Alkaline that claims to have long life. I have no information on this other than what is in the Radio Shack catalog. For me the best choice is good alkaline batteries and to replace them or just remove them when dead.

BASE STATION SIGNAL IMPROVEMENT

It has been suggested that adding a ground plane to the antenna of the base station would improve the operation of the wireless cabs. One of the suggestion that I read was to use a pie tin with a hole in the center for the antenna. I was in Safeway and saw the aluminum pie tins at 3 for $1.50. These are a very thin aluminum that is a little thicker than aluminum foil. I painted the 3 with black paint and then drilled a hole in the center that would allow the antenna ground to connect to the surface of the tin but not short to the antenna. (If you paint it be sure to remove any paint that would be in the area of the antenna connector.) One was installed on my layout and the other 2 were given to two others for use on their layouts. All three of the installations described the same results. Improved operation! You could tell that the signal strength was improved because the activity LED on the cab did not blink as much as it did before the ground plane was installed. The commands seem to act faster with the ground plane installed. This is a cheap way to get better operation out of you base station. If you need to see the activity LEDs on the unit, just cut a window in the pie tin. If you are creative a little paint and couple of LED can make the pie tin into a flying saucer.

Base on top with “Pie Tin” ground plane. (Tom Towner’s On3 Layout.)

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