President Grant Read Me

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These Modifications have been sent to me by Andy, here are the files that he
sent me:

--------------------------------------------------------------------------------

--------------------------------------­This Zipfile contains the following six files..

GRANTPLL BIN Contains the binary file that must be loaded to EPROM
GRANTXL BMP Schematic of PLL translator circuit to be contructed
READ_ME TXT This text file
CLARBEFR BMP Clarifier circuit of stock radio
CLARAFTR BMP Clarifier circuit of modified radio
FREQLIST TXT Table of frequencies for modified radio
OVER_MOD BMP How to modify your radio to over-modulate
MIC_BEFR BMP Mic preamplifier circuit in stock radio
MIC_AFTR BMP Mic preamplifier in radio modified for DC-bias-style
preamplified (or electret condensor) microphones

These files are strictly for experimental purposes and are not to be used on the
air.
(C)1999 Andy Moss files may be distributed as long as they are not modified or
charged for in any way. [e-mail]

Andy's words of wisdom on the Grant XL PLL modifications.......

I have not included step-by-step instructions for my PLL expansion modification.
However, anyone with a smattering of ignorance in PLL ICs, and a clear diagram
of the synthesizer part of the radio,
should have little if any problem adding this modification to the unit.
You will have to build yourself a small circuit board and I suggest you test it
before you install it into the radio.
Do not delete any of the components on my diagram!

You can use the Tone switch on the front of the radio as the band switch.
You'll have to put it right in the middle to select band three, but it does work
pretty good.

This modification will give you the standard 1-40 channels;
switch to band two and channel one becomes 41 and it goes up to channel 80.
With the switch in the middle position, channel 1 through 20 become channels 81
through 100;
21-25 become 3A,7A,11A,15A,19A.
Channels 26-40 are channels -15 through -1.

The FREQLIST outlines these channels.
The .BIN file is the "programme" you will have to burn into the EPROM.

It only uses the first two pages of memory so you could use a much smaller EPROM
such as a 27C08.
I used the 27C64 because it is getting hard to find smaller EPROMs.

Andy's thoughts on Crystal Channel Expanders................

A waste of time and money on the 148/XL as this radio does not use a ROM
middleman on the PLL.
I do concede that the Crystal Channel Expanders can be a good way to expand
radios with ROM PLLs.

Andy's words of wisdom on Over-modulation..............

I have included a modification to allow you to defeat the modulation limiter in
the XL/148. Don't do it.

If you must do it, wire it to your dimmer switch, or another SPST switch, so
that you can enable/disable it easily.
I've seen modifications that call for the changing of a couple of resistors in
the microphone pre-amp section of the radio.
Once again, don't do it.

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The components in the mic preamp of the radio are specifically chosen to provide

read_me

a certain pass-band of audio to modulate the radio.
This is VERY IMPORTANT on SSB. If you defeat this function you will decrease the
performance on SSB Tx - I guarantee you.

Andy's words of wisdom on adding a pre-amplified microphone......

I have included instructions on adding a radio-powered preamplified microphone.
I did this myself and use a Shure590T.
It was probably more of a pain-in-the-neck to do this than it was worth.
But, if you have a favorite
microphone, like me, you can use this modification and you'll be all set.

Andy's words of wisdom on modifying the clarifier...........

On the stock XL/148 the clarifier (aka Voice Lock) will vary only the Receive
frequency.
The tuning range is approximately +/-1.5kHz.
In my modification it will vary the Receive with the Transmit so if you tune
someone in,
you know that when you talk to them you'll be tuned in already on their end.
However, the tuning range of mine is approximately +/-6kHz.

Given that CB channels are 10kHz apart, you can see that my modification will
"catch" any activity between channels.
This is definately a worthwhile modification.

I've seen other modifications that allow you to tune from +2 to -13kHz.
These modifications are a little easier to do than mine.
There are a couple of problems with them.
If your clarifier is swinging that wildly, it can be difficult, and sometimes
impossible, to tune in stations that are off-frequency.
The radio will not be stable with the clarifier turned all the way to the "-"
side.

There is no benefit in going lower than 6kHz if you use my channel expansion
modification above anyway!

Andy's thoughts on power and "swing" modifications..........

Cranking up this radio, and most any radio, is usually a waste of time.
If you crank it up, you will be in danger of over-driving the output circuit of
the radio.

This will cause the output to be "dirty" and will profoundly increase the
possibility of causing interference to TV sets and other CB users.
It will also make your signal less intelligible on SSB and AM. It will only
shorten the lifespan of the components, run the radio hot and generally kill it.

Swing mod's. These typically are reducing the carrier power and increasing the
modulation.
What this does is ensures that your output is distorted.

Your radio will be running in DSB instead of AM.
It will make you sound louder to the locals.
Guess what? Your signal won't travel nearly as far as a stock unit because your
carrier is necessary to demodulate your sidebands at the receiving end!

Of course, it will splatter so the "extra power" that you're generating will be
on other channels - which isn't particularly useful for the person you are
talking too.
If you really want to run more than the legal output of power add an outboard
amplifier and run the radio as it was intended. 4W AM with 100% modulation and
12W PEP on SSB.

This may sound outrageous, but this is the way the radio works best!

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