Out of Band Programming

Taking a P100/HT50 out of band is VERY simple.

Unlike later Motorola products, the archive file is actually a straight hex/binary file. Just program everything except the frequencies like you want it, and save the archive. Use your favorite text editor to fix up the frequency info and save it.

Then, read the archive with the RSS and, without making any changes, program the radio.

If you attempt to program an out-of-band frequency, the code plug WILL accept the information. However, the RSS will notify you that the frequency is out-of-band and to "Return the radio to Motorola for service".

If, for instance, you convert an HT-50 to amateur service, what is needed after programming is a field alignment. This essentially consists of aligning the (4) receive helical resonators per channel for maximum noise, as well as adjusting the PA for each channel for maximum output. If aligned properly the receiver is quite hot. The HT-50's are capable of +-5MHZ out-of-band. Attempts to go farther than this range will result in a very unhappy PA section and a very deaf receiver.

The only bad news is that the VCO is a sealed unit. So, some P100's will go farther out of band than others, and there is no alignment "tweak" to extend the range. Most will do at least 2MHz and some as much as 10 or so.

Out of Band Programming, Method 2

This method should work for VHF radios.

For out of band programming, just edit the last 3 bytes before FF FF FF FF series at the end of the archive file. They should be changed to 06 45 36 from 03 78 36.

This should open up the full VHF range for the radio.

The only limitation you will run into is the VCO. Depending on how far out of band you go, you may find degraded RX sensitivity, low TX power, or both. If you go too far, the VCO may unlock completely, and the radio will not TX/RX on that channel.

Channel Expansion

It is relatively easy to convert a 2 channel to a 6 channel. If, the unit in question uses the 2/6 channel controller.

Be aware, however, that there were a few units built with a 2 channel only controller and cannot be converted.

The 2/6 channel controller is a NTN5239, the 2 channel controller is a NTN4862. According to the service manual, the NTN4862 was used only in models ending in 7120AN, but I don't think this is entirely accurate, so it is best just to open up the radio and have a look. The controller number is stamped on the flat side of the controller and is visible without any serious disassembly of the radio.

The conversion involves changing the selector switch from a 2 position toggle to a 6 position BCD and adding the 2 wires for the '2' and '4' positions. Then just program it with an archive from a 6 channel unit. The P100 RSS performs no serial number or model number check at all.

We would suggest obtaining the P100 service manual before attempting this upgrade. It will have the part numbers of the switch, knob and escutcheon needed. If your P100 is a low power unit (no Hi/Lo switch), use the old freq switch to add the Hi-Lo function. All P100's are built with the High power final Amp anyway!

The service manual shows a different part number for the top cover for a 6ch vs. a 2, but the only actual difference is the diameter of the hole for the freq. switch, so just drill it out a bit to mount the rotary switch.

Cloning Information

Basically, the cloning cable is 2 programming cables hooked together.

	Source		Description	Target
	Pin1		Ground		Pin1
	Pin6		Busy		Pin6
	Pin15		Data		Pin15

Pin numbers are for the DB25 end of the programming cables.

Cloning Procedure

General Information

A bad voltage regulator chip in radio causes a howl or microfonic RX.

There are three separate sources of five volts coming out of the regulator IC. Remove the bad regulator IC. It is best to cut the shield loose and break the IC loose by flexing the IC and the leads will break off.

Tie the three five volt lines together at the IC pads, and install a small three lead five volt regulator IC.

These radios can also have severe frequency drift due to the zener diode that regulates the 6.8 volts at this reference oscillator.

If you need the pinout of the microphone connector for the HT50/P100 then check here.