I've also got the SMC version of the user manual - SMC took over the manufacture of the HF150 from Lowe for a time - and it explains more fully how to use the keypad. The manual file is too big to attach either as a .PDF or a .ZIP, so I have transcribed the bit about the keypad below. It will be interesting to see how much of this works for you Steve, it depends, I think, on whether your keypad is the original one based on the remote control IC or the V2 based on a microcontroller. I know for a fact that mine won't do the shift-number function for mode selection because it doesn't scan for more than one key held down.
Cut out and keep:
-------------8<----------------
Code:
KEYPAD ENTRY
If you plug in the optional remote keypad then you can tune the receiver by entering
frequencies directly. This is very useful for quickly checking stations at known
frequencies, or for setting the frequency in a particular band of interest and then
searching for signals with the main tuning knob. The keypad is separate from the
receiver so that it can be positioned alongside for convenient use. It is connected
by a short cable which should be plugged into the KEYPAD jack on the rear panel of
the HF-150. The keypad has 12 keys - the digits [0] to [9], the [#] key (enter) and
the[*] key (Cancel). As keys are pressed the digits are shown on the receiver's
frequency display.
Frequencies are entered in Kilohertz. The receiver will only tune to the entered
frequency when it is complete - either when sufficient digits have been keyed in
or when the enter key [#] is pressed. Frequencies above 3000KHz will enter
automatically as soon as the last digit is keyed. Those below 3000KHz should be
followed by the enter key [#].
For example
[1] [2] [0] [9] [5] tunes to 12.095MHz
[1] [9] [8] [#] tunes to 198KHz
Supplement to 'Keypad Frequency Entry'
The keypad is now being replaced with a re-designed internal configuration which
employs a small micro controller to decode the keys and output the data. While
the physical layout of the popular keypad has been retained a few extra features
have been included which still allows the keypad to be used with previous Lowe
receivers i.e. HF125/HF225.
The frequency entry remains unchanged, with frequencies of 3000KHz and above
being automatically selected as the last digit is entered on the keypad.
Frequencies of 2999KHz and below are selected with the [#] key as the last
digit.
HF-150 users may also access the different modes in any order by holding down
the '*' key and then using any of the numbers 1-8 as indicated by the keypad
diagram below.
Keypad V2 layout showing mode selection via keypad.
[LSB] [USB] [AMn]
[ASL] [ASU] [AM]
[ASD] [ASF]
[*] <------ Shift Function
Because frequencies entered by the keypad are to the nearest kilohertz, it
may be necessary to retune the receiver slightly to correctly resolve single
sideband signals or when using the receiver in AMS mode.
If you press an incorrect key on the keypad, the current digits can be cleared
by pressing the cancel key[*], after which the frequency should be re-entered.
Please note that once keypad frequency entry is started the other controls
on the receiver will be inoperative until entry is completed or cancelled.
There is quick access to frequencies stored in the receiver's memories. If a
number between 1 and 60 is keyed in, followed by the enter key [#] then the
appropriate memory is recalled and the receiver's mode and frequency set. To
key in a frequency below 60KHz, prefix the number with a zero.
For example
[2] [#] recalls memory 2
[4] [5] [#] recalls memory 45
[0] [4] [5] [#] tunes to frequency 45 KHz