received this on packet:
 Msg# TSF  Size #Rd  Date  Time From   MsgID        To
30546 PY   4803   1 03-Dec 1626 G7IED  27645_GB7LAN WA2ISE ()
 Sb: C528

Here is a little mods list I find the 40ch mem a bit messy so
I don't use it and you can get the phone tones by pressing
the ptt and a number on the pad.
Hope this is of help to you
73s
Ralph

V7
The 520/28 is very flexible capable
of TX RX on 122.825 to 176.800MHz
and 328.000 to 473.125MHz.
And RX only on 820.225 to 972.500MHz.
The following are not in the owners book.
F=FUNC L=LIGHT
______________________________________
There are two ways to set Rx wide band
if you press reset you will need this
(A)
1  F + VHF
2  F + 0
3  F + D
4  RELEASE F
5  PRESS UHF
6  F + 0
7  F + D
8  F + L
9  F + B
10 F + 3
11 F + 0
12 F + 3
13 F + 0
14 F + 3
15 F + L
TO CANCEL RESET?
______________________________________
(B)
1  F + 0
2  F + D
3  PTT ON 145.00MHz IS DISPLAYED
4  PRESS VHF
5  F + L
6  F + 0
7  F + B
8  F + L
9  F + 3
10 PTT ON 433.00MHz IS DISPLAYED
TO CANCEL RESET?
THE RX IS NOW WIDE BAND
FOR TX CONTINUE BELOW
______________________________________
TX WIDE BAND PROCEDURE
1  VHF
2  F + 6
3  CHANGE FREQUENCY STEP FROM 10KHz
   TO 12.5KHz BY ROTARY SELECTOR
4  PTT ON 145.00MHz IS DISPLAYED
5  F + 8
6  F + 8  CONFIRM T AND + IN DISPLAY
7  F + 7
8  F + 7
9  F + C
10 SET 144.9875 BY ROTARY SELECTOR
11 CONFIRM THE SMALL 75 ON DISPLAY
12 F + 0
13 F + D
14 PTT ON
15 F + 8
16 F + C
TO CANCEL RESET?
_____________________________________
TO TOGGLE BETWEEN 3-400 AND 8-960 MHz
1  SET MAIN BAND TO UHF
2  F + 0
3  F + 3
______________________________________
DIRECT 4 DIGIT KEY INPUT
1  F + 0
2  F + 4
DISPLAYS A . BETWEEN 2nd AND 3rd DIGIT
TO CANCEL REPEAT ABOVE
______________________________________
10 MHz SHIFT BY UP/DOWN KEYS
1  F + 0
2  F + 9
TO CANCEL REPEAT ABOVE
______________________________________
40 CHANNALS MEMORY
THERE ARE 2 MEMORY CHANNELS PER MEMORY
NO ON VHF AND UHF.  THEY CAN BE USED IN 2 WAYS.
(A)TO PROVIDE PROGRAMBLE RX TX FREQUENCIES
(B)TO DOUBLE THE SIMPLEX CHANNELS AVAILIDLE
(A)
1  SELECT RX FREQ (VFO MODE)
2  F + D
3  PRESS MEMORY NO TO BE PROGRAMMED
4  D
5  SELECT TX FREQUENCY
6  F + D
7  F + THE MEMORY NO TO BE PROGRAMMED
+ - WILL APPEAR INDICATES THAT MEMORY
CHANNEL IS IN SPLIT FREQUENCY MODE
ONCE A MEMORY IS IN SPLIT MODE IT 
CANNOT BE CHANGED BACK TO A SINGLE
MEMORY UNLESS ITS PROGRAMMED AS A
EXTRA CHANNEL (SEE BELOW) OR RESET
F + 9 WILL SWAPP RX AND TX
(B)
EXTEND TO 40 MEMORIES
PROGRAM FIRST 10 MEMORIES IN EACH BAND
TO PROGRAM ADDITIONAL 10 MEMORIES
1 SELECT FREQUENCY (VFO MODE)
2 F + D    _
3 F + A AN M WILL APPEAR
4 PRESS MEMORY NO TO BE PROGRAMMED
TO RECALL EXTRA MEMORIES USE ROTARY
CONTROL IN MEMORY MODE OR ENTER MEMORY
MODE AND PRESS
F + A
THE M AND BAR APPEARS PRESSING
0 TO 9 WILL RECALL EX CHANNELS
THE EX CHANNELS CAN HAVE REP SHIFT
AND CTCSS TONES BUT VALUE WILL BE THE
SAME FOR BOTH CHANNELS IN ONE MEMORY
______________________________________
DTMF CLONE
COPYS YOUR SETTINGS TO ANOTHER 520/28
TUNE BOTH RADIOS TO SAME FREQUENCY
1  B P IS DISPLAYED
2  B C IS DISPLAYED
3  F +  0
4  F + PS
5  PTT ONLY ON THE RADIO THAT CONTAINS
THE MEMORY DATA
A SERIES OF TONES WILL BE HEARD FOR
APPROX 2 MINUTES THE RADIO MEMORYS 
WILL NOW BE IDENTICAL
______________________________________
DTMF SINGLE TONE
1  F + 0
2  F + 7
TO CANCEL REPEAT ABOVE
______________________________________
MUTING THE AUDIO OUTPUT OF PAGER
1  F + 0
2  F + 5
TO CANCEL REPEAT ABOVE
______________________________________
TONE SQUELCH SCAN STOP
1  F + 0
2  F + 2
TO CANCEL REPEAT ABOVE
______________________________________
H.H.TRANSPONDER SUB BAND TO MAIN
1  F + 0
2  F + 8
A . APPEARS TOP RIGHT OF MEMORY NO
TO CANCEL SET SUB BAND ON CLEAR FREQUENCY
BY ROTARY SELECTOR AND PRESS UHF OR VHF
_____________________________________
TOGGELS BETWEEN 100KHz AND 1MHz STEPS
ON ROTARY SELECTOR WHEN FUNC IS PRESSED (FAST TUNING RATE)
1  F + 0
2  F + 6
_____________________________________
SET FREQUENCY LIMIT ON EACH BAND
1  F + 0
2  F + 0
______________________________________
SET TX HANG DURING TRANAPONDER FUNC
1  F + 0
2  F + 1
______________________________________
Be very carfull with the h.h.transponder
and wide band tx func.

73s Ralph
G7IED @ GB7FCI