-----------------------------------------------------------------------------
The Complete (and Mostly Accurate) Guide to Undocumented Features
           of the Kenwood TH-78a Handheld Transceiver

                          02 Feb 94

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

PURPOSE: This file contains descriptions of all the undocumented features
of the TH-78a I could find as of this date. It doesn't attempt to explain
anything covered in the manual, but it does pass on pointers to interesting
uses of documented features (such as using message write 0 as a start-up
screen).

VALIDITY: This file supercedes the following: th78a-0.mod, th78a-1.mod,
th78a-2.mod, th78a-complete.mod, th78a-new.mod, th78a-warn.mod. I've run
this file by the authors of those mod files, where I could find them. Be
assured that you have the best information about the TH-78a we could put
together.

WARNING: This information is furnished without guarantee or warranty.
Working with surface-mount diodes is delicate work. Or as Eric Williams
(wd6cmu@netcom.com) so eloquently says "Lawyer bait: If you screw up your
radio, it's your own damn fault, don't blame me. (But it worked on mine.)"
These modifications (mods) may or may not work on your particular unit
according to Kenwood. I certainly accept no responsibility for your
handiwork or your transmitting on frequencies that you're not allowed to.
You may have good reasons to transmit outside of ham bands as I do during
search and rescue work (typically on CLEMARS, NLEMARS, and CALCOORD).

ACCURACY: Please mail me (Michael Sattler, KE6DZF) at msattler@jungle.com
if you see any omissions or mistakes. Make sure to pass along the date of
the version you're seeing (it's just under the title).

THANKS: Thanks be to all those who helped me, including
George_Lin@mindlink.bc.ca, Brendan_Hoar@notes.pw.com, rfc@allegra.att.com,
wd6cmu@netcom.com, elendir@enst.fr, nyu@flute.aix.calpoly.edu

AVAILABILITY: I'll attempt to have the latest version of this file (named
"th78a.kensho.mod") placed at the following mod servers:

Server  Directory
-------------------------------------------------------
ham.eetech.mcgill.ca    /pub/ham-radio/mods
(aka atlas.eetech.mcgill.ca)
bubba.business.uwo.ca   /mods/
garfield.catt.ncsu.edu  /pub/hamradio/HAM_MODS
kilroy.jpl.nasa.gov     /pub/hamradio/Mods
ftp.geo.brown.edu       /pub/hamradio/rigmods
(no longer accepts anons)

And one mail server:

pcserver@novell.business.uwo.ca
examples of main body email requests are as follows:
HELP
SENDME RADIO MODS
SENDME TH215 MODS
SENDME ALLBAND MODS

SCOPE: Ever since this guide has been loosed on the net, every so often
[someone] asks:

>Would you happen to know a similar list for the Kenwood TH-77A (next one back)
>Hand Held or the TM-721A (way back) mobile radio?

I would not know about radios other than the one I own, sorry. I compiled
this guide from old mod notes, tidbits I found on the net, and personal
experience. I'm guessing that there are others out there that have done the
same for their radios; I suggest that you look through all the mod servers.
(If you know of other mod servers, please let me know.)

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Contents of this file

What is a "new" TH-78a?
Basics of modifying the Kenwood TH-78a
Potential case design flaw
C-17 design flaw
Mutually exclusive mods
The "beyond MARS" mod
The "CAP/MARS" mod
The "extended receive" mod
The "cross-band repeat" mod
Toggle SHIFT button function
Toggle CALL button function
Observations on post-mod performance
Cloning
Cellular Telephones
Battery life on the TH-78A
The TH-78A (USA) vs. the TH-78E (European/Japanese)
CTCSS
Frequency range differences
Customizing the start-up message
TH-78a loses the call channel CTCSS tone Greg Hammond's Receiver Tests
Stuff that didn't fit anywhere else
Game Mode

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What is a "new" TH-78a?

Kenwood says that any TH-78a with a serial number greater than 405xxx is
considered a "new" TH-78a. I've not authoritatively determined the
difference between the old and new models, but the mods differ, so it's
worthwhile to check the serial number. The ARTSCI 5A techmod book calls
this the "Later Model (with green jumpers)". I use the terms "early model"
and "late model" throughout this document.

William_A._Kirsanoff@smtpgty.anatcp.rock says:

"I can tell you the difference between an "old" and "new" TH-78A. The "old"
78As had a fault in the microprocessor resulting in an inability to store a
pl tone in the call channels (and possibly some other bazaarities). People
who complained got the new processor installed by Kenwood when it became
available (there are actually 2 microprocessors in the HT, I think the one
changed is IC 5, mine has a paper label pasted over it). It seems they also
added the jumpers on the programming diodes, probably to keep hams from
using their soldering irons on the SMC diodes while making mods. :-) When
my "old" unit was upgraded to the new processor, my mods from removing the
diodes remained in place."

-----------------------------------------------------------------------------
Basics of modifying the Kenwood TH-78a

To open the radio, follow the instructions on page 64 of the manual.
(Unscrew four screws and break apart the radio halves.) The two TX/RX busy
indicators (LEDs) have rubber seals placed over them. These have a tendency
to fall off when opening or closing the radio.

All position references in this document assume that you are looking at the
CPU board with the rotary encoders and TX/RX busy indicators at the top. If
you have installed the ME-1 EEPROM, I recommend that you temporarily remove
it to facilitate access to the diodes.

You'll see a brass shield about one centimeter square covering the
processor chip and the surface-mount diodes on the back half of the radio.
De-solder the shield's four corners and remove it. (I used an right angle
surgical tweezers in conjunction with the pin-point soldering iron to lift
the brass shield.)

Uncovered are the processor (which we ignore) and six surface-mount diodes,
numbered sequentially from one through six (D1 - D6), top to bottom. These
are about one millimeter wide; remember the note about skill and finesse.
New model radios also have two large loops of green wire, numbered one
through two (W1 - W2), bottom to top.

You'll need a pinpoint-tip soldering iron and some braid to wick away the
solder before you lift out the diode. Alternatively, Rich Garcia
(n2czf@wt3v.nj.usa) suggests leaving the diode in place. "I found if you
BRIEFLY touch the iron to the right side lead while gently pulling up on
the SMC diode it should completely come off without needing to apply heat
to the other side and further risk board damage."

After you perform some or all of the mods listed below, replace the brass
shield and re-assemble the radio. Then reset the processor (as documented)
and re-enter any frequencies into memory.

-----------------------------------------------------------------------------
Potential case design flaw

>From wb1e@k1rqg.me.usa.na (which no longer exists):

In the course of performing mods on my Kenwood TH-78a dual band handheld,
I've discovered a potential flaw in the case design. While handling my
walkie one day (after the mods were done), the display went blank and I
could not turn the radio back on. With the radio split in half again, I
could turn the radio back on but discovered all the memories were erased.
The cause turned out to be some component pins on the front face coming in
contact with the square bodies of the two volume/channel/squelch switches,
when the case is screwed back together snuggly. I placed small strips of
electrical tape on the sides of the switches to insulate, and reassembled;
problem solved. Now I have to reprogram the darn thing....

molson@bml4380.cpg.cdc.com (Mark Olson) said:

There is a warning on some of the rig mod bulletin boards about this. The
problem is that pins on the back side of the PCB that is mounted on the
front half of the TH78 can come into contact with the volume control
housings mounted on the PCB on the other half of the unit. My radio had
this problem until I put electrical tape across these housings. Symptoms
were: Display blanking momentarily and the unit power cycling, sometimes
causing memory erase, when pressure was applied to the front of the unit or
to the volume controls. I originally thought that it was a loose battery
connection...

Open up the radio and you will see what I mean... Believe me, the fix is
simple and it works.

-----------------------------------------------------------------------------
C-17 design flaw

William_A._Kirsanoff@smtpgty.anatcp.rockwell.COM said:

"The 78A WILL lose C-17 on the control board if dropped, period. This
causes loss on receive audio on the left-hand side of the radio. The solder
pads for that cap are not big enough. If you find the need to replace C-17,
use a gap-fill cyanoacrylate glue like Zap-A-Gap (tm) to increase the
device footprint. I have learned the hard way. Otherwise, I have found it
to be a fine radio. My only problems have been related to the C-17 issue
and attempts to rectify it. Had I been given the above advice, it would
have been a one-time only issue. As it is, I took out one of the
microprocessors yesterday looking for a bad solder joint that was induced
by my attempt to solve the C-17 problem (sigh). This radio gets a lot of
use and a lot of travel. C-17 is the only thing that I have broken with the
case closed. :-)"

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Mutually exclusive mods

Some of these mods are reputed to be mutually exclusive. You must choose
one of the following levels of performance:

The "beyond MARS" mod - gets you the widest tx/rx The "MARS/CAPS" mod -
halfway there
The "extended receive" mod - more of a good thing

plus

The "cross-band repeat" mod - a repeater that weighs almost nothing

There is no mods that manipulate diodes D1 or D2 (I've seen it suggested
elsewhere that this is toggles the USA/Europe-ness).

Brendan_Hoar@notes.pw.com suggests:

"I think removal of D1 causes "Forced Channelized Mode", at least on the
"new" radios. If you put both VHF and UHF memories into a TH78A without D1
and
power on, you are stuck in channel mode until you do a full memory reset.
Remember, you can't add frequencies or do any tuning in channel mode.

If you think about it, you'll want to be very careful not to let D1's
circut become an open circut."

The "beyond MARS" mod:
---------------------

This mod provides the widest possible range of tx/rx. The mother of all
TH-78a mods.

To mod (early model): remove diode D5 only.

To mod (late model): remove diode D3 and cut wire W1. D5 has priority over
D3, so if you've already made the mods for the old model (which included
the removal of D5) you must resolder D3 into D5.

Yields RX 50-179.995, TX 136-179.995, RX 300-399.995, RX 400-511.995, TX
400-511.995, RX 800-999.995.

To use: buttons operate the same way as described in the "extended receive"
mod, except that you can transmit on a much wider range.

NOTE TO ALL: I haven't been able to verify the actual operation of my radio
on all these freqs. Kenwood talks about the difference between the
"dialable" range and the operating range. I'd like to come up with a chart
for each level of mod that combines the above and the two following
offerings. Help me, please.

* * * * * * * * * * * * * * * * * * * * * * * * * * * *

Left VFO        Right VFO
50.000-85.2x (with beep)        50.000-110.xxx (with beep)
85.2x-179.995   110.xxx-179.995
300.00-399.975
400.000-511.9875        400.000-511.9875
800.00-999.9875

* * * * * * * * * * * * * * * * * * * * * * * * * * * *

Receive Transmit
--------------- ---------------
50-135.995 (AM) VHF     (NA)
136-179.995     "       136-179.995
300-399 (AM & FM)       "       (NA)
400-511.99      SUB-UHF 400-511.99

400-511.99      UHF     400-511.99
900-949.9875    "       (NA)
50-179.995 (FM) SUB-VHF 136-179.995


The "CAP/MARS" mod:
------------------

This doesn't cover as much room as the beyond MARS mod does, but may be
more appropriate for those who use the CAP or MARS frequencies.

To mod (both early and late models): remove D6 only.

Yields RX 118-173.995, TX 142-151.995, RX 400-511.995, TX 425-454.995.


The "extended receive" mod:
--------------------------

This is the mod that's usually given to hams to pacify them (the beyond
MARS mod is closely guarded).

To mod (both early and late models): remove diode D5.

To use: press 'F' for one second and then pressing the Band button will
switch the UHF VFO to a 800-999.995 MHz band and the VHF VFO to a
300-399.995 MHz band. The regular VHF VFO can now receive down to 50 Mhz.


The "cross-band repeat" mod:
---------------------------

Allows you to... (WHAT!?!)

To mod: remove diode D4.

To use: press 'F' for one second, then '0'. Repeat to disable. The MHz dot
will flash when in repeater mode.
-----------------------------------------------------------------------------
Toggle SHIFT button function

Press SHIFT during power-up This is described in the manual, but the
documentation is not complete. The TH-78A can operate in two modes: In
SPLIT mode, non-standard offsets (i.e. split frequencies) are supported,
but the default offset is not programmable. In SHIFT mode, non-standard
offsets are not allowed, but the default offset is programmable. To select
the default offset, press F for 1 second, then SHIFT. See p. 30 of the
manual for details on changing the default offset.

-----------------------------------------------------------------------------
Toggle CALL button function

Press CALL during power-up. The CALL button can operate in one of two
modes. In the default mode (CALLSW), it switches between the call channel
and the last memory channel (if in memory recall mode) or last frequency
(if in VFO mode). After toggling the CALL button functionality (VMC), it
will switch from the VFO to the last memory channel and then back to the
CALL channel.

-----------------------------------------------------------------------------
Observations on post-mod performance

Rich Garcia (n2czf@wt3v.nj.usa) observes "all original functions have
maintained the same which is great. Aircraft band which was accessible
before the mod remains with the same characteristics. It seems that
VHF-High band has improved a bit on sensivity where it was dead as a dog
before the mod (above 155.000MHz) but the 162.000 MHz band where weather
radio is is still a bit deaf for reception at any distance but about 20
Miles. This depends on your (or my) terrain and transmitter output power.

"On UHF all public safety frequencies up to about 500 MHz seem to come in
well but sensivity greatly drops from there (we really can't ask for more).
Frequencies can be programed in up to the 920MHz ham band but I have no way
of measuring sensivity. 800MHz works but the signals are very weak, you
must be near the transmitter for reception. Assuming you are in the town or
city where the transmissions originate it should work.

"Transmit is enabled up to and incl. 500MHz but after testing this on a
frequency counter I find that a signal is only generated to about 490 MHz,
even though the trans. LED shows output in the higher frequencies.

"Crossband repeat seems to work fine but the audio is unacceptable for use,
BE AWARE the radio gets HOT! Prolonged use or use on a busy frequency would
not be recommended. Also remember this is a dual band HT please use a
proper antenna while in this mode to avoid a high SWR, we should all know
better... Right?"

Someone else said:

"I found that marine weather reports at 162.40MHz in my area were received
much better on the SUB-VHF band, than on the VHF band...

"If you are having problems with intermod, try switching bands (i.e. using
the SUB-VHF band rather than the VHF band.)"

blood@vnet.IBM.COM says:

"I did the beyond Mars mod for the newer model. All worked as described.
One note however, I seem to have lost the automatic repeater shift
function."

elendir@enst.fr (Elendir) speaketh from across the "pond":

"Hello, I have a TH 78E (European version) and I have made the "beyond
MARS" mod. I found this afterwards :

The key combination POWER + CALL acts as a toggle on the CALL key. Either
the CALL key has it nominal function or the CALL key acts as a V/M/C scan
initiator. (In the manual, it is said to be possible for US version only).
Does the US version acts similary or is it a specific behavior?"

shortly thereafter he sent a follow-up:

"Ok, it was a little mistake. It doesn't act as a V/M/C automatic scan, but
a V/M/C switch. I mean if you are using the VCO, CALL switches you to the
CALL channel, then to the most recently used memory channel, then back to
VFO.

Also, the combination POWER + DUAL displays something like "SAMPLE".
Anybody knows what it is about?"

-----------------------------------------------------------------------------
Cloning

The TH-78a's memory can be copied from one TH-78a to another TH-78a
entirely through radio waves "over the air" (i.e. without cables or other
special equipment). Theoretically, this could be done via repeaters,
although I've never heard it done. Allegedly this requires a mod that
includes removal of D5 or D6, but I haven't researched it.

Cloning is a real boon to groups that want a bunch of radios to contain the
same memories, such as amateur radio clubs, search and rescue units, and
people too lazy to program their radios. Of course, given that the ME-1
memory expansion unit has 250 memories, laziness is understandable :-)

(1) Set both radios to the same frequency.

(2) Activate both radios by pressing the '0' key while turning the power
on. The radios will display the word "clone".

(3) Now, click the PTT button of the "master" radio. The radio will
transmit in the economy low power mode. This may take about 4 minutes for
fifty channels, or 20 minutes for the 250-memory ME-1. When the data has
been transferred, both radios will revert back to their original frequency.
(It is recommended that a dummy load be used to prevent unwanted
interference.)

(4) Turn both radios off and then on again. The slave is now a mirror-image
of the master radio.

-----------------------------------------------------------------------------
Cellular Telephones

Cellular phones operate at (tx) 824.040 - 848.970 (rx) 869.040 - 893.970,
within reach of your modified TH-78a. The increments are, however, every
30kHz; the TH-78a will only increment in 25kHz steps at this frequency
range, so the exact cellular frequency cannot be tuned in (most of the
time).

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Battery life on the TH-78A

wd6cmu@netcom.com (Eric Williams) says:

Some people have complained about the battery life on the TH-78A. I came up
with these tips by checking out the power consumption under various
configurations. In the case of power-saver mode, figuring out the average
current with my DVM was impossible, so I ran the radio on a large capacitor
and timed how long it took to die. These tips won't solve everything, but
they might help.

The rig draws close to 2ma even with the power turned off, so don't leave
the rig off with the battery installed for several days and expect full
capacity to be maintained.

If you're only using one of the bands, shut down the other to extend your
battery's life -- current consumption with the squelch closed is cut by
almost a third.

If you're monitoring two frequencies on the same band, use the f2 button to
receive both simultaneously rather than scanning between them -- the
battery saver with two receivers will use about half the current of one
receiver that is scanning.

You can make up a battery pack by putting nickel metal hydride AA cells in
a BT-8 battery holder. A small strip of aluminum from the positive battery
terminal to the depression in the top of the case will allow you to
recharge the pack inside the rig. This will give you 1000mah capacity
without enlarging the size of the radio, and NiMH cells have no memory
effect. (But they *are* expensive.)

-----------------------------------------------------------------------------
The TH-78A (USA) vs. the TH-78E (European/Japanese)

CTCSS:
-----

Eric Williams (wd6cmu@netcom.com) reminds us that:

>The manual says that the CTCSS module is an option on the European model, but
>standard on the U.S. one.

Vince (elendir@enst.fr) replies:

>That's ... because [the French] repeaters are activated by a 1750-hertz tone.
>If I intend to go to US this summer, must I buy the CTCSS module ?

biocca@csg.lbl.gov (Alan K Biocca, WB6ZQZ) says (and I paraphrase):

>While it varies geographically, where I am (Lawrence Berkeley Laboratory,
>California) very few 2-meter repeaters require CTCSS tones, most 440 MHz
>repeaters do. Many of those that do are closed anyway. You can probably get by
>without them.

gsm@mendelson.com (Geoffrey S. Mendelson, N3OWJ) tells us:

>It depends on where you are. In the Philadelphia area most of the open 440 MHz
>repeaters use CTCSS and none of the 2-meter ones do. At least one uses CTCSS
>for remote inputs.

>About 60 miles away in southern New Jersey, all of the 2m and 440 repeaters
>use CTCSS.

Frequency range differences:
---------------------------

Someone (I've forgotten who) suggested:

>Um, I'm pretty sure that the unmodified UHF TX range is different.

Kenneth E. Harker (kharker@bnr.ca) wrote:

>These are the VHF - UHF bands authorized in France :

>50.2 to 51.2 with a special authorization. 144 to 146
>430 to 440 (shared band)

Whereupon Lawrence "The Dreamer" Chen (dreamer@lhaven.UUmh.Ab.Ca) said:

>In North America the authorized bands are:

>50-54
>144-148
>220-225 (222-225 in US and soon to be Canada) 420-450 (420-430 is only by
>special permission) and its a shared band.

>I would guess that the TH-78E only does 144-146 and 430-440 while the TH-78A
>does 144-148 and 440-450.

torsten@rnivh.rni.sub.org (Torsten Leibold) summarized for us:

>Yep, you're right. The A version is the American version and the E stands for
>Europe. The E version does 144-146 MHz and 430-440 MHz without modifications.
>(I guess there are some secret codes to switch it to the "A"-bands, but I
>don't know them).

I don't know of any "secret codes", but I'd heard that D1 toggled between
'A' and 'E' performance. Unverified. -- msattler

-----------------------------------------------------------------------------
Customizing the start-up message

William_A._Kirsanoff@smtpgty.anatcp.rockwell.com says:

Just in case you are doing a message write, don't pick slot '0', that would
change your start-up message (default is "TH-78A", mine is "KD6MCI" :-) )
You can then crack open the manual and read up on how these features work.
I use the autodialer regularly. I don't have much use for the message
memory other than the start-up trick though.

-----------------------------------------------------------------------------
TH-78a loses the call channel CTCSS tone

George_Lin@mindlink.bc.ca says:
>Michael Sattler writes (regarding George's comments):

>Can you come up with an easy procedure for the readers of the guide to check
>whether their particular TH-78a loses the call channel tone? (I want to hear
>what you do, rather than make something up.)

Sure.

Go to the oscillator on the right (UHF oscillator). Select a UHF frequency
on the VFO. Set the CTCSS tone frequency to some arbitrary number, say,
94.8 Hz. Turn on the CTCSS. Save the whole thing under the call channel for
UHF. Select another UHF frequency. Select another CTCSS tone. Turn the
subaudible tone on and save it under a spare memory channel. Go back to the
call channel and check the tone frequency.

Greg Hammond's Receiver Tests

gregh@swifty.dap.CSIRO.AU (Greg Hammond) in a rare moment says:

"Some time ago I did a quick comparison of TX power output between the
TH78A, the Alinco DJ580 and the Standard C558. The Kenwood had BY FAR the
highest power output at 477MHz."

Greg's done both RX and TX power measurements of the TH-78A; the RX numbers
follow and the TX numbers are forthcoming. As I can't make head nor tails
of these numbers (remember, I have to wait for the soldering iron to get
hot to figure out which end's which :-) I'd appreciate your comments on
Greg's work.

Test conditions.

Powered from 7.2 volt battery pack.
Single band mode used.
All figures are for NFM mode unless stated otherwise.

Method.

FM mode: The audio output from the earphone jack was measured
with an AC millivolt-meter. A calibrated RF generator was connected to the
antenna BNC. The RF generator output level was increased until a 12db fall
in audio ( noise ) was measured. The generator level was recorded in the
'Sensitivity' columns below. There was no modulation on the RF signal.

AM mode: Same as above except the generator level was adjusted so
that changing the AM modulation from 0% to 90% caused a 12db increase in
audio output. The modulation frequency was 400Hz.

Sensitivity was measured at the displayed frequency and the 1st. IF image
frequency. Note that sometimes the TH78A is more sensitive at its image
frequency. ( 395MHz to 430MHz is best received by tuning from 305MHz to
340MHz )

Image freq. = Displayed freq. +or- ( 1st. IF freq. * 2 )

TH78A Receive sensitivities. ( MAIN UHF )

First IF = 58.525 MHz

Signal Sensitivity      Image Sensitivity
MHz     uV      MHz     uV

400     33      282.95  235
405     4.8     287.95
410     2.5     292.95  990
415     1.2     297.95
420     0.58    302.95  1200
425     0.28    307.95
430     0.18    312.95  1800
435     0.18    317.95
440     0.16    322.95  1750
445     0.22    327.95
450     0.34    332.95  260
455     0.9     337.95
460     2.1     342.95  185
465     4.4     347.95
470     9.3     352.95  160
475     17      357.95
480     39      362.95  160
485     94      367.95
490     130     372.95  155
495     225     377.95
500     400     382.95  90
505     670     387.95
510     1350    392.95  23





TH78A Receive sensitivities. ( Sub UHF )

First IF = 45.05 MHz

Signal Sensitivity      Image Sensitivity
MHz     uV      MHz     uV

400     4.63    309.9   2920
405     2.85    314.9   2190
410     1.64    319.9   1230
415 0.693       324.9   468
420     0.32    329.9   184
425 0.224       334.9   200
430 0.191       339.9   200
435 0.166       344.9   129
440 0.155       349.9   94.5
445 0.137       354.9   66.1
450 0.135       359.9   36.4
455 0.137       364.9   19.5
460     0.2     369.9   13.2
465 0.372       374.9   11.9
470 0.751       379.9   9.34
475     1.37    384.9   10.6
480     2.49    389.9   8.72
485     3.59    394.9   5.32
490     3.94    399.9   2.22
495     3.64    404.9 0.956
500     3.76    409.9 0.583
505     4.27    414.9 0.625
510     5.25    419.9 0.742
515     6.03    424.9 0.924
520     6.93    429.9 0.945
525     7.42    434.9 0.913





TH78A Receive sensitivities. ( Main VHF )

First IF = 45.05 MHz

Signal Sensitivity      Image Sensitivity
MHz     uV      MHz     uV

90      1.9 AM  180.1   1.48
95      1.32 AM 185.1   2.09
100     0.95 AM 190.1   4.68
105     0.75 AM 195.1
110     0.49 AM 200.1   33.1
115     0.4 AM  205.1
120     0.33 AM 210.1   234
125     0.26 AM 215.1
130     0.25 AM 220.1   933
135     0.24 AM 225.1   1780
140     0.14    230.1   600
145     0.13    235.1   980
150     0.14    240.1   2100
155     0.16    245.1   8400
160     0.24    250.1
165     0.33    255.1
170     0.5     260.1
175     0.76    265.1
180     1.1     270.1





TH78A Receive sensitivities. ( Sub VHF )

First IF = 58.525 MHz

Signal Sensitivity      Image Sensitivity
MHz     uV      Mhz     uV

110     1.8     227.05  410
115     0.69    232.05
120     0.4     237.05  655
125     0.32    242.05
130     0.32    247.05  785
135 0.258       252.05
140     0.2     257.05  1502
145 0.165       262.05
150     0.15    267.05  7400
155     0.15    272.05
160 0.175       277.05
165 0.168       282.05
170 0.225       287.05  6200
175 0.335       292.05  2150
180     0.44    297.05  1200





TH78A Receive sensitivities. ( Sub UHF 320MHz, NFM Mode )

First IF 45.05 MHz

Signal Sensitivity      Image Sensitivity
MHz     uV      MHz     uV

305     1.59    395.1 0.324
310     1.32    400.1 0.285
315     1.06    405.1 0.232
320 0.832       410.1 0.189
325 0.646       415.1 0.178
330 0.576       420.1   0.17
335 0.372       425.1   0.18
340 0.335       430.1 0.186
345 0.351       435.1 0.214
350 0.412       440.1 0.292
355 0.519       445.1 0.324
360 0.685       450.1 0.427
365 0.924       455.1 0.625
370     1.28    460.1 0.924
375     1.7     465.1   1.26
380     2.17    470.1   1.76
385     2.6     475.1   2.54
390     2.99    480.1   3.31
395     2.27    485.1   3.2





TH78A Receive sensitivities. ( 900Mhz )

First IF 58.525 MHz

Signal Sensitivity      Image Sensitivity
MHz     uV      MHz     uV

800     1.46    682.95  178
810     0.8     692.95  237
820     0.56    702.95  442
830     0.51    712.95  232
840 0.525       722.95  82.3
850 0.617       732.95  49
860 0.814       742.95  35.1
870     1.15    752.95  27.3
880     1.46    762.95  17.8
890     1.89    772.95  11
900     2.49    782.95  7.34
910     2.95    792.95  4.47
920     3.17    802.95  2.63
930     3.2     812.95  1.68
940     3.24    822.95  1.32
950     3.35    832.95  1.19
960     3.64    842.95  1.16
970     3.94    852.95  1.22
980     3.99    862.95  1.28
990     3.68    872.95  1.35
1000    3.28    882.95  1.34



-----------------------------------------------------------------------------
Stuff that didn't fit anywhere else

Early on, msattler@netcom.com (Michael Sattler, KE6DZF) mentioned:

>I've had one report that the TH-78A is capable of in-band full duplex
>operation. I've been unable to repeat this on my unit, which only has the
>CAP/MARS mod perform. Confirmation of this feature would be appreciated.

nyu@flute.aix.calpoly.edu (Neal, KD6HPG) replied:

>My friend (N6RNF) has a "early" model radio and it was capable of doing
>in-band full duplex. I have a "later" model of the TH-78A and I can't get it
>to work on mine. My friend's radio has the beyond MARS mod.

-----------------------------------------------------------------------------
Game Mode

ORIGIN: aviator@athena.mit.edu (who no longer exists), who credits
james@brokaw.lcs.mit.edu for "much of this".

To enter the game mode press M and PTT during power-up. Be careful not to
accidentally reset the memory, which happens with M + power-up. (Don't
freak; you'll see the same "all screen items lit" when entering game mode
as when you reset memory.) To exit the game mode at any time, press the
LAMP key. The volume, lamp, or frequency settings can't be changed while in
game mode.

The top part of the display will show "H.00", which represents the high
score. The lower part shows a scrolling message, "PRESS ANY KEY". Pushing
any key starts a "Follow Simon" type game. The display will briefly show
one of the characters '1', '2', '3', or 'F'. Press the corresponding key.
The game consists of repeating the displayed character sequence, which
increases by one character each round.

After you "win" the Simon memory game by getting correctly entering a
sequence of twenty characters, the next game is a draw poker game.

The way it works is that you choose your bet (from 1 to 10) by pressing '2'
to increment the bet and '5' to decrement the bet. Then, press 'F' to deal
the five cards. The face value of the cards is displayed, and the suits can
be seen at any time by holding down the PTT key. Any number of cards may be
discarded, and to select (or deselect) a card for discarding, press the
keys '1', '2', '3', '4', or '5'. If a card is selected for discard, it is
displayed "face-down".

Press 'F' again to draw new cards. Your new cards will be displayed, and
then if your hand is 2-pair or better, the screen will show the rank of
your hand on the left (2P for 2-pair, 4K for four-of-a-kind, etc.). On the
right the pay-off for that hand will be displayed. Your bet is multiplied
by the pay-off factor,and the resulting pile of cash is displayed in the
right hand side of the upper screen. (The left-hand side of the upper
screen contains your table stakes, which are initially 100 coins from
winning the Simon game.)

If you win the poker hand, pressing any key steps into the next stage. If
you lose the poker hand, your bet is deducted from your stakes and you are
asked to start another poker hand. In the next stage, you are asked
"TRYB/S" which means, "Do you want to try double-or-nothing in a guessing
game for Big or Small cards?" Press 'F' for yes, press TONE for no. If you
say no, your winnings are credited into your stakes and you are asked to
start another poker hand. If you say yes, then a single
shuffling/incrementing card is displayed on the left, and three stars are
displayed on the right. You have to choose to go for either BIG or SMALL,
by pressing '2' or '5'. You can keep pressing '2' and '5' to change your
mind. When you are ready, you must try to hit the 'F' key to stop the
rotating card display, and the card will show, and you will either win,
lose, or draw. If you draw, you have to play big/small again, I think. If
you lose, your winnings are gone and you can play poker again. If you win,
your winnings double and you are asked whether you want to play big/small
again.

The payoffs on the poker are set against you, odds-wise; the
double-or-nothing game includes a draw, so the odds are against the player
there unless you can time hitting the 'F' key to win more than half the
rounds. I haven't managed to do this, so I don't know if there is anything
beyond this, all I know is that when the table stakes are exhausted, you go
back to playing Simon again.

----------------------------------------------------------------------------
This is the end of The Complete (and Mostly Accurate) Guide to
Undocumented Features of the Kenwood TH-78a Handheld Transceiver.
----------------------------------------------------------------------------
