Modifications for the Kenwood
TH-79
19-07-1998 TH-79 clone memory contense of two
radio
Dear friends
Hope a lot of you enjoy to play with the TH
79. I want to explain how to clone the memory contense of two radios on the air.
The clone procedure is same with all others. ( use of DTMF tones, do not disturb
transmission etc.)
You must take care that both radios are really same: both
have extended range or not, both are E-version or not etc.
It will cause some
problems if you try to clone i.e. an E version without expansion into a A- or J
version.
If you have both radios please hold down the -0- key / PAG L Key
when you switxh on the radio. So you see the letters CLONE on the display.
Please push the ptt on the radio which has to be the master.
It takes a time
to transmit all memory with maybe names, call sign etc.
After Clone is
finished you see END written in Display. Best is to switch of both radios. After
switching on again you will have two same radios !
Enjoy it and best
wishes..
73 from hanno
19-07-1998 TH-79A extended RX and TX range
for new radio
Remove diodes D304 and D307.
Thats all...Don't
cut the green wire, or install any jumpers as before.
Just take out these
diodes...A WHOLE lot easier than moving and jumpering..
With this mod the
capability is same as the other mod, ie: 67-174.995 and 400-511.995 RX,
136-174.995 and 400-511.995 TX.
Mine wouldn't recieve all the way down to 67
MHz, but it did go to 85 MHz.
It changes to AM receive below 136 MHZ
automatically.
My TX power was gone above 505 MHz but was solid elsewhere in
VHF and UHF.
Enjoy, but don't create problems with the new
capability...Wouldn't it be nice if Kenwood would make a RX only mod with these
capabilities and we wouldn't have to worry about accidental transmissions where
we shouldn't be transmitting. I, for one, don't want or need to TX, just
RX...
73, Cole AA7RDAugust 11, 1994
19-07-1998 TH-79A Wide Band
Modification
Following is a modification for the Kenwood TH-79A
Dual Band HT which opens it up to tuning from 67-174 MHz and 400-511 MHz. Actual
receive was 85-135.995 AM and 136-179.995 FM with reasonable (0.5 microvolt or
better) sensitivity at all the points I measured. Transmit was 136-179.995 and
400-511 with power dropping off at the ends but still usable (about 0.5w on the
high scale at the band edges).
This mod is the official one from Kenwood,
taken from a data sheet put out by them. It supercedes an earlier one I posted
involving moving some diodes. As usual, I take no responsibility for the mods,
or your use of the unit after mod. Please exercise good judgement and don't
endanger our ham bands with your irresponsible
actions.
WARNING-CAUTION-LOOKOUT-ETC!!!
The diodes to be moved are
microscopic!! About 1mm long by 0.5mm wide.
This mod should be done by
professionals on a closed track only.
Children, do not attempt this at home!!
Requires extremely small soldering tools and MUCH skill.
- Open the unit by removing three screws from the back and one under the DC
power input cover. Carefully separate the front and back pieces. The two case
halves may be disconnected by pulling the wired plug and by prying the brown
latch on the ribbon cable connector up enough to release it.
- On the front PC board in the lower right corner as viewed from the rear
with the knobs pointing up there are seven spots for diodes in a row, with one
diode missing.
| o o o o x o o |
________________|
2 3 4 5 6 7 8
The numbers are D302-D308, left to right, with D306 missing.
- Remove diodes D304 and D307.
- Reassemble and apply power. Mod complete.
PS:
Just cutting the
green wire by the recharging jack is the MARS mod.. Don't cut if you intend to
do the above mod.. Good Luck.Cole AA7RD
19-07-1998 MARS/CAP modification for the new
Kenwood TH-79A
Here is the MARS/CAP modification for the new
Kenwood TH-79A dual-band HT. Usual disclaimers about doing mods apply.
- Remove battery.
- Open case by first removing 3 screws (#00 Phillips) on back and 1 screw on
side hidden underneath the rubber flap covering the DC power jack. Gently pry
apart starting at top; BNC connector will move with back, knobs with front.
- Spread unit out. Wires will "hinge" on the side with the PTT button.
- Looking on the back of the keypad (front) half, locate green wire on upper
left, just below the CTCSS decoder module.
- Neatly cut this green wire, and tuck back in so ends won't touch each
other or other components.
- Reassemble.
Programmed memory will be lost since the CPU will
notice the strap change and reset itself.
End result -
Before: VHF RX - 118.000-173.995 TX - 144.000-147.995
UHF RX - 438.000-449.995 TX - 438.000-449.995
After: VHF RX - 118.000-173.995 TX - 142.000-151.995
UHF RX - 420.000-449.995 TX - 420.000-449.995
Automatic repeater offset and shift selections remain normal.
If I read
the schematic right, the green wire corresponds to "W301", which also serves the
same purpose as removing "D308". More research needs to be done on other mods;
I'm especially interested in extending UHF receive beyond 450. There is a row of
diodes right below the uC which appear to be D302 through D308, the
configuration straps. HOWEVER - I need to caution anybody thinking about playing
with the diode straps that it will not be a casual operation. For one thing, the
diodes are SMD "603" style - extra, extra tiny - and the plastic board
hold-downs molded into the front case are right on the landings for most of the
diodes. This means that the board will have to be removed from the case (a very
involved procedure), and working with the tiny diodes *will* require
magnification tools as well as the correct micro-tip iron. It is not a job for
the inexperienced or all-thumbs.
Also, as noted previously, the non-US
versions of the TH-79 have an 800 MHz receive section. All RF components of this
section are not present in the US version. Frankly, it would easier to import a
gray-market version of the radio than it would be to attempt restoring this
coverage in the US with parts.
...mike musick/N0QBF
19-07-1998 Hidden options
TH-79
Playing around with my Kenwood TH-79 handheld, I discovered
some "hidden" possibilities that are not mentioned in the user
manual.
A. Clone:
Action to be taken by both stations:
- Switch power off
- Press both the PTT and the VFO key, and keep them pressed while switching
the power on
- Switch power off again
- Press the PAG.L key (figure zero) and keep pressed while switching on the
power again Now, in the display the indication CLONE will appear
As
soon as the station that will transmit presses the PTT switch for a while,
cloning will start. This will take several minutes.
After cloning is
finished, the transmitting station's display will return to "normal", whereas
the display of the receiving station will indicate END.
B. Switching
to other VFO's (other bands)
As you may know, in the menu 4 VFO's are
possible, namely menu nrs. 13, 14, 20 and 21. Menu 13 and 14 being the
"standard" VFO's for vhf and uhf and menu 20 and 21 for the bands 300-399 Mc and
800-999 MHz.
It appeared to me that the vhf band (menu 13) can be
switched to 300-399 Mc (menu 20), whereas the uhf band (menu 14) can be switched
to 800-999 Mc (menu 21).
Just make the band you like to change the active
band (PTT indication in the display near to the frequency) and then first press
the function key, followed by pressing the LOW(hi/lo/el) key.
Needless to
say that in order to be able to receive those "alternative" frequencies the
handheld should have been modified (in my case I provisionally did cut the green
wire).
I hope you will enjoy these "hidden" options.
In case I do
discover more of them, I will share them with you.
On the other hand, if you
have further information on hidden options and/or modification I would be please
to know them as well.
Best 73 from
Hans - PA3ESZ @
PI8VNW.
19-07-1998 TH-79
WIDEBAND-RX ONLY
Yeahh, this is the modification you all have
been wating for !!!
Recently I purchased a TH-79A in the United States
having the idea that is was possible to convert it to a model TH79E.
After
some research i discovered that it was possible to make a TH79E.
Inspired by
this succes i wanted to have the extra RX possibilities, and after the so called
'green-wire' cut i had the wanted RX but also TX. Because of government
regulations this extra TX it is not allowed in Holland. So i searched a little
farther and fixed the job.
The following modification is called the E3
modification.
This modification gives you:
TX 430-440 MHz and TX
144-146 and RX for all built in frequencies that the hardware of your radio is
capable to receive.
What to do ?
Find some one that can manage very
tiny SMD components. Cut the green wire and change your diodes under the CPU so
that it looks like this:
X X - - X X X X X
R D D D D D D D R
5 3 3 3 3 3 3 3 4
0 0 0 0 0 0 0 0 0
2 2 3 4 5 6 7 8 2
X = component present
- = no diode here
R = Resistor
D = Diode
R 402 and R 502 are only displayed for reference.
Hint ! in the SCHEMATIC DIAGRAM you received with your radio there is also
a diode program diagram wich lists the E3 version and other versions
also.
For example the K version is the American version. Please note that
in this table D 302 and D 305 are not drawn, and have to be
present.
Background information:
I chose for the E3 type because i
had a modification note of the TM 733.
In this note i read what the different
type's (letters) had for operating RX/TX frequency's.
So if you want to find
out what the other types would do see if you can put your hand on this TM 733
modification note.
WARNING:
The radio you purchased is very
expensive, don't give me the blame if something does not work.
If you
diside to make this modification is on your risk only !!!
THIS IS A
SPECIALIST JOB BE WARE OF THE TINY COMPONENTS !!
For stations who live
nearby i can give assistence.
REMARKS
Only the normal TH79E
HARDWARE is capable of receiving 900 MHz.
This is not possible for the other
versions.
FINALY
I hope you will enjoy these "hidden"
options.
In case I do discover more of them, I will share them with
you.
On the other hand, if you have further information on hidden options
and/or modifications I would be please to know them as well.
Best 73
from
Ron - PE1OZH @PI8EZQ
19-07-1998 Umbau TH79e auf
9k6
From: DG3MMU @ DB0KCP.#BAY.DEU.EU
(Andreas)
Hier kommt ne Anleitung zum Umbau des TH-79e auf
9k6.
1. Oeffnen des Gerätes:
Alle Stecker incl. Antennenkabel
abziehen, den Akku entfernen.
Auf der Rueckseite des Geraetes die 3 Schrauben
loesen, ebenso wie die kleine Schraube an der Seite beim Antennenanschluss.
Vorsichtig das Gehaeuse oeffnen. Nun die Haelfte mit der LCD-Anzeige nach links
legen, und die andere nach rechts (wer haette das gedacht :-)
Falls ein
CTCSS-Modul drinne ist, kommt das auch raus :-)
2.
RX-Modifikation:
Die vier Schrauben in der (ich nenn sie mal)
"Power"-Haelfte (mit den beiden HF-Hybrids und dem vielen Kupferblech)
rausschrauben und vorsichtig rausnehmen. Dazu muss noch die BNC-Buchse
weggeloetet werden.
Auf der Unterseite gibts nen IC Marke Motorola MC3372D
(Demodulator), der ist fuer UHF. Das RX-Kabel wird da am Pin 9
angeloetet.
Damit ist der RX-Ausgang vom UHF-Empfänger IC schon mal fertig
:-)
3. TX-Modifikation:
Im zweiten Gehaeusedeckel (mit den Potis
und den MIC/Lautsprecher-Buchsen) gibt es eine "Tochterplatine", die den
Mikrophon-Amp beherbergt.
Einfach die Platine runtermachen, ein Draht an den
Widerstand neben dem IC 308 (TA75W558F) und das ist die
TX-Einspeisung.
Ich hoffe, in der kleinen Zeichnung kann man was erkennen
:-)
Der Draht wird am oberen Kontakt vom R angeloetet (wo das R steht),
der betreffende Widerstand ist ein groesserer Widerstand als es die andren
sind.
+------------------------------+
! R + !
! ## + ***(IC308) !
! ## *** !
! ## !
! ## !
! ## !
+------------------------------+
Steckkontakt zur
grossen Platine
Wenn fertig, wieder die Platine auf den Kontakt stecken.
4. Letzte
Schritte:
So, die typischen 2 Draehte sind angeloetet, ist auch keine
Bruecke unerwuenscht entstanden ?! OK, dann das ganze Geraet in umgekehrter
Reihenfolge wie beim Zerlegen unter Punkt 1 wieder zusammenbauen, kurzer
Funktionstest, und dann kann das ganze schon an das FSK-Modem angeschlossen
werden.
Gedanken muss man sich nur noch über die Verbindung zur
Aussenwelt machen, entweder einen kleinen Platinensteckverbinder (3-polig und
einen Pol davon abfeilen) oder eine 2,5mm Monobuchse (passt wahrscheinlich
ebenso nur abgefeilt rein) ins Geraet reinbauen.
Ich uebernehme keine
Verantwortung für die Richtigkeit der in der Anleitung gemachten Angaben und für
Schaeden die im und am Geraet durch die Modifikation entstehen. Die Anleitung
ist etwas groesser geworden, dafür aber (hoffe ich) einfacher und auch für
Nicht-Profis (etwas Loeterfahrung braucht man schon!!) verständlich.
Ok,
73 de Andy DG3MMU @ DB0KCP.#BAY.DEU.EU
19-07-1998 Kenwood TH-79A(D)
Review
The TH-79A(D)'s approach to programming is largely
intuitive, and that's an advantage when you're trying to become acquainted.
Jumping from memory channels to VFO (and back) is as simple as pressing a single
button. The same is true for hopping from 2 meters to 70 cm, or vice versa. When
you're in the memory mode, twisting a single knob will step you through the
channels. The same knob functions as a free- wheeling frequency control when in
the VFO mode.
If you forget how to use a specific feature, the "guide"
function is ready to assist. Simply press the F key followed by the GUIDE
button. By rotating the ENC knob, you're presented with a list of functions.
Each is described with text flowing from right to left across the display,
Thanks to Kenwood's unique dot-matrix LCD, the scrolling instructions are easy
to read.
After you've programmed the TH-79A(D), you can share the
contents of the memory channels with other TH-79s through a wireless cloning
feature. In fact, one TH-79A(D) can upload data to several others at
once!
Several team members commented favorably on the multipurpose timer
functions.
A battery-saving mode shuts down many of the energy-intensive
functions if the radio is not used after 10 seconds. The time-out timer answers
the prayers of many long-winded hams. If your favorite repeater drops out after,
say, three minutes of continuous babble, you can program the timer to cut you
off well before then. (The TH-79A(D) simply drops back to the receive mode.)
Finally, the TH-79A(D) offers a timer that shuts down the radio completely if it
hasn't been used for one hour. All of these timers are programmable, or they can
be disabled altogether.
One interesting feature of the TH-79A(D) is not
mentioned in the manual, although it is mentioned in the advertising: AM
aircraft receive capability.
As it turns out, the TH-79A(D) has a hot
aircraft receiver. Team members enjoyed listening to airliners in contact with
Boston Center, or on approach to Bradley International Airport near Hartford,
Connecticut.
The TH-79A(D) was judged awkward in only one respect: the
operation of the squelch. There is no squelch control on the TH-79A(D) in the
traditional sense (a knob). Instead, you must select among several squelch
levels by bringing up the appropriate program menu. Most team members didn't
find it too objection-able, but it might drive you up the wall if you're the
type who often fiddles with the squelch.
Reprinted with permission from
JULY 1995 QST, © ARRL
19-07-1998 Remote Base Operation with Kenwood
732/733
Kenwood has now simplified remote base operation of their
mobile rigs with the TH79.
I will not give a step by step on how to
control the mobile rigs, since they are different. Hoewever, to really
understand this feature, I would first get to know the remote control feature on
the mobile very well. This makes the following explanation a little
clearer!
To access this feature, hold [PTT] and [MR] while [POWER
ON].
The display will indicate -RC-, which I presume means 'Remote
Control'.
If you have correctly matched your DTSS codes, frequencies,
etc, the dual bander's keypad now becomes a function pad. Pressing certain keys
enables or disables functions on the mobile rig by sending the DTMF sequences
for you.
Please note that all this fuction does is send the DTMF tones
over the air to control your mobile rig. I have not made a list of what each key
does, but as the 79 sends the DTMF tones, the display will indicate the
function. (i.e. - RPT ON, RPT OFF, TONE ON, TONE OFF, etc.)
73 de Clayton
KD4IDN
And this from Chuck Scott, N8DNX...
"The "RC" function
is configured to directly control radios such as the TM-732. In fact, if you
look at the layout of the microphone remote commands for the 732 it very closely
matches the key assignments for of the "RC" mode. Since I have a TM-732
installed in my car, I had a chance to try this out and it's VERY convenient.
Everything from direct frequency entry with the "F" key to enabling X-Band
repeat. I'm really surprised they aren't marketing this feature of the
radio.
19-07-1998 Post
Modification Spec Sheet
Author:
Clayton Wagar, KD4IDN
Here is a small chart showing the measured
specifictions of TH79 S/N 60300272 after modification. The measurements were
made with an IFR 1200S Service Monitor, on the bench, with a 6V power supply.
Your milage may vary - these are just what happened with mine, and I would
suspect that most units are pretty similar.
73 de Clayton
KD4IDN
Band - VHF -----------------------------------------------------
Frequency Sens (uV) Power Mode
--------- --------- ----- ----
108 4 - A3
110 2 - "
115 .75 - "
120 .40 - "
125 .30 - "
130 .30 - "
135 .30 - "
140 .12 2.9 F3
145 .12 2.9 "
150 .13 2.8 "
155 .15 2.4 "
160 .18 1.9 "
165 .20 1.45 "
170 .21 1.10 "
175 .30 0.85 "
179.995 .35 0.70 "
Band - VHF (2) (set to 300Mhz) --------------------------------
Frequency Sens (uV) Power Mode
--------- --------- ----- ----
300 50/75 - A3/F3
320 4/20 - "
340 .3/.6 - "
360 .2/.5 - "
380 .2/.6 - "
400 .2/.75 - "
Band - UHF -----------------------------------------------------
Frequency Sens (uV) Power Mode
--------- --------- ----- ----
400 11 1.0 F3
410 4 1.5 "
420 1 1.85 "
430 .2 2.2 "
435 .12 2.3 "
440 .10 2.5 "
445 .10 2.5 "
450 .10 2.5 "
455 .15 2.3 "
460 .16 2.3 "
465 .20 2.0 "
470 .45 1.8 "
480 1 1.6 "
490 2 1.3 "
500 6 1.1 "
510 no RX over 509 0.8 "
19-07-1998 Cross Band
Repeat
from Chuck Scott, N8DNX
The TH-79 does go
into X-Band repeat. Press the "F" key then the "MONI" key to enter repeat
mode.
Use the same to return to normal.
There is a 10 min transmit limit
so it's not useable for long duration monitoring of a continuous transmission.
That's understandable in light of the number of horror stories I've heard of
people frying their HT's in repeat mode.
03-01-1999 TH-79 Save function &
packet!
From: [email protected]
From some
testing I've done it looks like it's necessary to set the SAVE mode on the
TH-79's menu to OFF for proper packet radio operation.
When this function
is ON, my PR system misses the first FBB UNPROTO updates after an update request
(originating from my station) unless another packet arriving in between the
request and the first UNPROTO packet 'wakes' up the TH-79.
If not woken
up the RX seems to miss (some of) the first update packet and Winpack shows only
the second and following, which generates repeated requests for an update of the
message list. The updates go to the FBB Unproto buffer, but the BBS system keeps
repeating them all over and over again including one final time when the first
FBB UNPROTO update does happen to get registered and the buffer
clears.
When I first got the TH-79, I measured current consumption and
saw it going down during standby without a signal, then when a signal was
received the current would go up and stay 'high' for a rather short while after
the signal had disappeared and then it would go to sleep again. This behaviour
is present when the SAVE mode is enabled. I assume the squelch is too slow for
packet when the SAVE mode is enabled. (I need to have the squelch at position 4,
btw, because of digital noise on 144,675 MHz.)
Does anybody else have the
same experience with the TH-79 SAVE mode and the FBB UNPROTO updates?
tu
es 73 de Arjen, OH2ZAZ@OH2RBI
Current QTH: Helsinki - KP20LD