New Firmware for the PRM8030/8025 It has been done… Here is new firmware for the PRM80 that gives us full control of all the VHF/UHF Ham Bands
In my previous article I showed how to convert an E band PRM80 radio to 6 metres, using nothing more than basic RF principals and some “outside the box” thinking to get the PLL down to 50Mhz. This all worked very well apart from a couple of side effects.
If you didn't see the other article, these side effects were Microprocessor noise on parts of the band and the lack of a repeater defeat option due to the hacked reference stepping.
While converting another E band PRM80 to six metres, I got thinking about the firmware and how the “words” are added to the PLL to not allow it to go below 58Mhz. So silly me started trawling through lines of code to find a pattern that looked familiar and I found it…..
I have on a link below, a modified firmware for the PRM8025 and PRM8030 and now the Dual Mode 8025/30. It may work on the PRM8038 but this has not been tested. It will work with PMR and Dual Mode type radios. This firmware has the following changes:
What this means is that the FPP software will still show the original Phillips designed frequencies, you still enter them as Phillips want, just the radio will behave differently. Here is an example for each band:
I was initially just going to change it for the 6 metre conversion and then I got carried away. There is 2 hidden bands in the firmware (called K1 and K3 I believe) that we cant access with our Australian software, it would have been nice to be able to use them, I could have left 4 metres in for our English mates.
It is possible if your radio had version 2 or lower of the Phillips firmware in it that it will make a beep-boop sound indicating that the software is corrupt. In most cases this can be cleared by loading a new job file to the radio but not always. If this does not work, you will have to have a look on the internet for a program called FP (Factory Programmer) and do a “re-format” of the radio's software.
Both side effects have been fixed by using this firmware. The repeater defeat button now works as the correct codes are loaded into both RX and TX. The microprocessor noise I was getting across the band has disappeared. I can only surmise that using the 8Mhz rock and already having a 12Mhz rock on the control board were mixing and causing all sorts of havoc. (we get 8, 12, 4 and 20Mhz and multiples of them).
If you have already done the conversion from my previous article, all you need to do is remove the 8Mhz crystal and replace it with the original 10Mhz one and change the firmware. The RF stages are all the same.
We now have a radio that is suited to all the ham bands from 29Mhz to 440Mhz depending on what RF board is installed. Here is a list of the frequency ranges now obtainable using the FPP software without band swapping or HEX editing:
|W4||24 - 50Mhz||10M|
|E||48 - 68Mhz||6M|
|B||108 - 132Mhz||Aircraft|
|A||146 - 174Mhz||2M|
|U||220 - 250Mhz||American 220Mhz|
|T||400 - 440Mhz||70cm|
|TU||403 - 470Mhz||70cm, Police RX|
|W1||470 - 500Mhz||UHF CB|
|UW||450 - 520Mhz||UHF CB, Police RX|
or if you feel like HEX editing (the higher value is an estimate as it depends on the step size):
|W4||10 - 75Mhz|
|E||38 - 99Mhz|
|B||100 - 180Mhz|
|A||140 - 200Mhz|
|U||190 - 320Mhz|
|T||380 - 500Mhz|
|TU||400 - 520Mhz|
|W1||445 - 565Mhz|
|UW||440 - 560Mhz|