The FOXBOX

Number 9 on your Feedback card
The FOXBOX
A voice ID T-hunt controller.
by Rex Drake KISGH
D
o you need a simple, effective controlter
ror use during foxhunts'? I wanted such
a devicc, but was unable to find one that
i i t my dcsires. Most controIler circuits use
somc form of PROM chip. which 1 did not
want to use. I did Find a controller circuit'
thilt used 8-bit shirt registers to form a pmgramrnubie memory. To get the required
number of programmable bits to create the
memory, the device needs 16 register chips.
Buying this many chips could become expensive and the device still can only operalc in
cw.
I was browsing through the local Radio
Shack and Found a chip which intrigued me.
The ISDIOOOA i s billed as a voice record
and playback 1C. Even though the chip is
somewhat expensive, the price is roughly
equal to. or slightly chcaper than. buying a
PROM or buying 16-shift register chips. The
lSD IOOOA can bc used to identify a hidden
tnnsmiltcr with voice, or in CW like thc 0ther controller circuits 1 discovered.
T h e ID Circuit
The ISD 1000A comes packaged with' application notcs2. Imade a few changes to the
"simple record and playback" circuit. The
chip has an addressable memory. I decided to
use the memory to store a single messageso the-addmssingcircuitry was not used. Iobtained the microphone recommended by the
application notes. The notes and the mike dntrt differ sIightly in the circuits required to
I
RC-99
Rarnsey, NJ 07446
REPEATER/REMOT E
CONTROLLER
800,3454634
Phone 8 FAX 201.327-2462
ONV Safety Belt With Seat Harness
FEATURES INCLUDE: Hang up proof User
Programmable InitiallNormal C W ID'S,
passwords and lirners IC.900 pgrn. ICOM HF
pgrn. with scan and offsets Seleclive Muting
Molex con. Complete Audio Interface Aux.
Outputs Key Delay Adlustment Sublone
lnpuls Small Size Telemetry Response
.
- .
.-
Version 2 cassette today!
KAWA RECORDS
T h e Timer Circuits
Two timers are required for the FOXBOX.
I used a 55'6 dual-timer 1C to reduce the circuit size. The _chip includes two separate 555
ONV SAFETY BELT CO.
P.O. Box 404
"THE RHYTHM OF THE CODE"
Serrd 19.85 and we'll pay Vle shipphg Lo:
power the electret mike. The data included
with the mike described a simpler circuit than
that included in $e notes. Iused the simpler
approach and have encountered no problems.
My final modil'ications were made to the
speaker output o f [he ISD IOWA. Iinserted a
1 k potentiometer (R II ) which can be used to
adjust the audio {eve1 sent to the transmitter. I
also included a 1 : I audio transformer to provide isolation between the ISDICQOA and the
transmitter. Other than these 'changes, I built
the circuit as described in the notes.
Worldwide
Ordw Desk Open
$149.00 Assembled and tested
Optional Autopatch $49.00
P.0. BOX319-ST
PLUSTEN
ONV Toot Pouch $15.95
1067 1 Main 51. Elbildge. N I 13000-1157
{315) 589-1340
(3151 6W-1345Fax
Overseas please add S2.00 lor air mail.
MA residenls ada 5% sales t a r
CIRCLE 2 ON READER SERVICE CARD
-
CIRCLE 396 ON RE4DER SERVICE CARD
CIRCLE 102 O N READER SERVICE CARD
From
Micro
Computer
Concepts
RC-1000
REPEATER
CONTROLLER
R
Autopatch Reverse Autopatch
User Programmable CW ID,
Control & User Codes & Timeouls
Manual with schematics
90-Day Warranty
Wired & Tested wl manual .... $239.95
Micro Comwuter Concepts
LISA ffl0 CAHnM ORDERS
FAN LlPDeRg (809 J.il,na
W
CIRCLE 187 ON READER
8841 Gum Tree Ave.
New Port Rlchey, FL 34653
-37
SERVICECARD-
42 73 Amateur Radio Today * March, 3994
813-376-6575
CIRCLE 198 ON READER SERVICE CARD
CIRCLE 160 ON READER SERVICE CARD
timcrs. Timcr f controls the ovcratl limc period uf rhe FOXBOX. Thc timcr is uscd in the
astable modc lo provide a continuous repenting cyclc. At thc cnd of every timer cyclc. the
ID circuit is activated. The time period is adjusrablc by use of a potentiometer for R4.
Thc cycle adjusts between approxirnnte[y 30
and 90 seconds. A 1 megohm pot, used I'or
R4. w i l l allow I"or timcr periods up to approximotcly 100 or 300 seconds.
The sccond rimer i s uscd to control the
lime the transmitter i s held i n the transmit
modc. Timcr 2 operates i n thc monostable
mudc. A trigger signal is needcd to start the
[imcr cyclc. which runs for n sct lime pcriod.
Thc triggcr signal is providcd by Timcr I at
t h t cnd ul'each of its cycles. Timcr 2's cycle
3Cljus~svia R I, providing 'rl p~riudo f I0 LO 25
seconds. Thc adjustable period allows kcying
o f tlic [rat~sn~i~tcr
only as long ns !he 1D mcs-
! built scvcral radio keying circuits hchrc
I fuund onc which works rcliably ia this iIpplicaiion. ! wantcd ro be able l o key sevcnl
dil'l'crcnt radios with he circuit. Therefore.
11w circuit could not be built spccificnlly for
any particular radio. One o f the requirements
I had Ibr this devicc was the ~ l e c t r i c a isoial
lion o f the timcr from the pdio's press-to-talk
(mjcircuitry. I wanlcd the isolation to prevent currcnt flow between the two circuits. I
did not want audio signals interfering with
the timer outpur. When using my HT for the
[ox, the mikc and PTT circuits have to be
placed in series.
I solvcd the keying probtem by using an
1 - Packet Radio - 1
/
1
Portable & Affordable!
optois013t0r. The aptoisolator IC conthins an
infrared LED and an infrared phototransistor.
The two cornponenrs are conncctcd only by
an i n f r a r ~ d l i ~ beam.
ht
The isolator's LED is
driven by theL'output of the transmit tilncr
SOLDER P L - 2 5 9 s A SNAP!
SOLDER
M I R I A T U R E CONNECTORS W I T H EASE
S O L D E R ALUMINUM AIYD MOST METALS
Solder.lt Is stronger and more conductive than regular
solder and since it is a paste, flows at lower temperatures
so you don't burn your work. Just apply and heat.
* N o External Powcr
k Smart Dogm Timer
-k Pcrhct For Portable
t Assembled Sr Tcstcd
* VHF, UHF, HF
(JOM)
Our Kit includes four different
Solder Pastes. A professional
grade precision refillable butane
Pencil Torch w ~ t hStand, Vinyl
Storage Pouch. Complete
Instructions, Warranty.
The Reviewers agree... read
CQ, Jan 3 993 J
QCWA Journal, Fall 1992 J
Nuts & Volts, Dec 1992 J
Wl~erl~ur
you' rc an expericnccri packclzer or a newcunler wanling to
cxplorc 1,nckcl for the first linrc, lhis is whal you've been waiting for!
Thxnks l o a brcak~hrwgh i n rlipital signal proccsx~ng, we l ~ n v o
rlcvclnpctl n t i r ~ y ,full-rcar~lrcri,pitclrcl nlorlz~nst JII u r ~ l ~ r c c c r l c r ~ t c t l
low price. The BnyPac Morizl BP- t Irallsroruls ynw P C - c o r ~ ~ p ~ ~ i h l z
culrlpulcr inlo a powcrful Packcl TNC.
capiible of suppru[ig ~ o p l u s ~ ~ c afcnlurcs
~ed
11kc dlg~peabnp, file ~ransfcrl, ant1 rcrnole
~ ~ r r n l nncccsg.
al
NOW is thc rlrnt: Cnr YOU
Iojoln the PACKET REVOLUTION!
.
.n r ask someone who has used
Solder-It.
FREE CATALYTIC TIP WlTH
ORDERS BEFORE DAYTON
Send $59.00+ $3.50 S&H for The
Solder-It Kit to
Solder-It C o . ,
P.O. Box 2 0 100 Dept. A.
Cleveland. OH 44 120
Check OK. Ohio add 7.5% Tax.
We ship in 48 hrs.
For inlo or COO orders call 21 6-721-3700
.
- -CIRCLE 263 ON READER SERVlCE CARD
11
CIRCLE 325 ON READER SERVICE CARD
73 Amateur Radio Today March, 1994 43
C4
22
R4
f OOK
>I
-
4
3
- 5
6
l2
7
9
8
'0
-
-
J3 Pin3
R12
IK
J3 Pin4
b 53 Pin1
1
.,-
.
2
,
) J3 Pin2
I
Figidre I. FOXBOX circuit schcrnaric. Nures: All copucitntlcc vaIucs
~ I rnicrofurcrd~.
I
For
ICOM n~rdsimilar HE,short pins 2 and 3 of J3.
age measured at the ndio's P l T pin. I is the
maximum current desired to llow through
R13. Try to set the current at about 20 mA.
Do nut let the current become greater than
100 rnA or the optoisolator could be destroyed.
Thc.optoisoIator 1 used i s not available at
Radio Shack. To build a FOXBOX entirely
from Radio Shack parts, a small SV relay
(#275-740) can be substituted for U4. R12,
(Timer 2). The LED current is limited by
R 12. When the LED is lit. the phototransistor
is turned "on." acting as a P I T switch to key
thc tmnsmitler. R13 limits the current from
the ndio's PTT circuit to avoid destroying
the phototransistor. The resistor value may
necd adjustment to allow reliable keying of
somc ri_gs. Ohm's Law can be used to calculate R 13.
Let R equal the value of R 13. V is the volt-
and R l 3 . The relay coil is connected directly
to the output of Timer 2. The relay's normally open (NO) contacts can then be used For
the PTT switch.
FOXBOX Power
The FOXBOX is designed to operate
from 8V to 12V battery power. The circuitry
actually operates at 5V. A 7805 voltage
regulator ( U I ) is used to achieve the nec-
Optional Clrcult
Original Circuit
p~~-a-:
5V Relay
U4
p
"
~
J
RS# 275-240
3
P
i
n
J3 Pln 2
-
l
J3
53 Pin
Pin 2f
-
Fi~rlre2. Original mrd oprionai keying cirrliitsfor the FOXBOX.
44 73 Amateur Radio Today March, 1994
Figure 3. PC board pattern and parts placement.
'
, -. .
, ,
Constru&,,~
;': .' ,. .. ,.
essary 5 volts. No filtering capacito;s are' -bugging, I built thi prototype on a 3" by 4"
uxcd; due to the DC input. Revtrse polarity
The entire device was constructed on a piece of pgrfboard. Perbard construction reprotection is provided by a 1N4Mll rectifier breadbard in o r e to debug the individual quires careful attention to correct wiring condiode.
. circuits before actual construction. After de- nections. A printed circuit board would be
<'%;-',
'<..k:,"';
p.,<
..
,
QUALITY ];THAT'S .,.;
:; ;!i.:-AFF'ORDAB
LE
.
.
, . , ., .
,
,;..
...I
.
Tri-Ex is b;le&-to
innounce the reductlon in price on .
the most popular models of quality Tri-Ex towers for the, Amateur radio enthusiast. The overhelming acceptance
of the listed models has made it possible for Tri-Ex to.'
pass on substantial savings to our valued customers.
LM-470
NOW1
WAS
-
$3,658
Was
Now
m-51 $1,245 $1,050
LM-354 $1,865 $1,300
TO O!DER
CALL
-
TECH SUPPORT 209-651-7859
FAX 209651-5157
AH towers are wmplete with rigid concrete base mount and
rotalor mourning plate. Ti-Ex prints and calculations pmuided
with lwvar are wrnp#ant with 1991 Uriforrn Building Code
(U.BiC.) Engineering deagned to 1991 U.B.C. - 70 MPH
I ~nI
High Performance
PacTOR / AMTOR
Use an ordinary RTTY terminal unit such as
CP-1, CP-100, TU-170, ST-6, ST-5000,
ST-6000, etc. with G4BMK's BMK-MULTY
software running ,in your IBM-PC or compatible.
A TNC is not needed! (but we do have an
adapter for PK232). Version 3 now available.
Detailed literature upon request. Prices:
Base communications package with AMTOR,
RTTY, CW and QSOlcallsign logging database
$95..Base + Pactor $145. Extended audio
package adds Audio Spectrum Analyzer, HF
WEFAX and SSTV reception. Base + Extended
$140. Base + Pactor + Extended $175. Pactor
alone $50. PK232 Adapter $49. Shipping $3.
VISA/MasterCard accepted.
Amateur callsign required with order.
Please state 3'/2 or 51/4 inch disk preference.
-m-T@
--
I
Schnedler Systems AC4IW
P.O. Box 5964
TOWER CORPORAmON
7182 RasmussenAve. Visdia, CA 93291
Umutuassed Qualifvsince 1954
DRCLE
46 73Amateur Radb Tday* March, 1994
ON READER S-E
Asheville, NC 28813
CARD
(704) 274-4646
Pin Asslgnrnents fo,-.tJ3,:,,;.,
. .. . . - . .. ..>,- - - .*,; ;
.;--.
.
.
. . -,
Pin . .;:..
. .. - '.. .. .
-'-.PTT.,,
f
-,,..,
-:,
F.
-<
*
--;
P l T Ground
Mlke
Mlke Qmund
,Note: For use with ICOM or slmllar handhelds, .,
jumper p b 2 and 3 logether In me InterIaca Eable
plug1
2
3
4
,
hclpful for preventing wiring mistakes.
I. mounted most of the componenB on the
top side of the circuit board. The three adjustable resistors and the microphone were
mounted an the underside of h e board. The
undefiidc mounting is due to the board's'l*
cation close to the inside of the caw. I drilled
three holes in the case in order to allow for
timer and mike level adjustments to be made
externally just before hiding the fox. A fourth
hoIe was made to allow direct access to the
microphone.
I chose to use a readily available ABS
plastic case, even though i t offers no RF
shiclding. To date, I hove not experienced
any problems with RF interference.
For hiding. I wanted to use a piece of
large-diameter PVC pipe to house the
FOXBOX and transrnit~cr.Thc pipe would
help with disguising thc fox and would also
provide protcrtion to thc devices insidt. Because the FOXBOX was to be placed in the
pipe. I wanted a11 of the external jacks and
Continued 011 puge 50
. ..+ - '.. -.-.
,;< >:
Part
-
.. ...
.
-
- + ,, .
.,
,
~ ~ ' ; ; ~.. ~ .:!
l .w
,
~:'. :!
.
., - ,,,.
:-
svregulator
556 dual Urner
1 4 d n IC socket
,
.., .-ISD1000:,. 28.ph IC--t
:, f . ;
-':I ::,,-"
- 4N28 optokoktor : '-;,
&pin IC soelret '
1W k PC mount pot
l m k : ,,-,
35k.
22k
470k
Ik
10
u1
TBOS
'
U2
.
1.
Ra
R9,R12,R13
RIO
TI
1:I audio tramlamer
Mlnl DPDT sllda swltch
S1,SZ
Jl
$2
273-1374
275407
274-1583 or preference
274-248
274or preference
Power Input
tla"speaker jack
5g)n DIN Cck
Electreltype
33
MlaophDne
2MQM
Optlml:
Perlboard
276-162 or 275188
Case
Size to Ill
Relay
SV SPOT mkm
275-240
Note: The relay, if used, would replace W, R12, and R13. See text.
A drilled and etched'PC board'kr Ihk protact Is available for $4.25~1~8
$1.50 SgH from FAR Clreuits,
1 at4640 Field bud,
O. <y. d..w .IL- M118...:2 : ;
.,
.
, .
,
::?,
';,,-
-
(2-5,10,11,f2 and 15)
FREE Technical Suppor~
16550s Standard
MasCerCard, VISA and COO accepted1
NexL Day Service available1
30 Day Money Back Guarantee
PRICE: $89.00
;
."
- , .>
!
.^
.
-*
.: ;I 4
Now
-
.
..
'
*und&;. Wind6w%DOiS
w.',.;
:r
Two RS-232 Ports with full Modem Control
Signals
.
.
.
.-.dm
Part; #3088
.
-
.
L*<$&~$$&Pafls,
. . ...,
. List
.'
.. .__...
.:-
.
,
-
.
,*,
- '
,.
;>**
>
. 4,
.,:; $.-,.,
-
,c--L'*.,
.x- .
i
,-
9-
'.='-<-+
,:*;,:*
l*rd.l~~g~--rlpdm---ndmWlnp#PCUd S s s m * r r ~ P r J r * 4 u r p H r r u . ) M r a d I h . ! 4 a n m
Y O I L U ~ U ~ Y D ~ ~ ~
mr rowlr MUw p m &-
-*mwws k q h ~ p r U r w * l l h E Y B ~
m E w m * A Bup.rvm
-L.pr--8km
Pmgunmw-
-4rnM.l-opmA*.hm
----h-
SEALEVEL SYSTEM3 INCORPORATED
P.O. BOX 830 102 W. MAIN 5T.
LtBEKlY, SC 29657
ClRCLE 364 ON R W E R SERVICE C M D
U R C E 220 ON REABER SERYfCE CARD
..a
'$ 73Amateur Radio Today March, 1994 47
The FOXBOX
-. . .
47
.
to he able to use two r!iI!'crtnt radios Tor the
hidden T.The first radio. an AIinco 570 uses
a lour-conductor interlhcc cable to carry PIT,
,
.
Enter the exciting switches at one end of the case. I achieved'- PTT ground, MIC, and MIC ground signals.
~ o r l dof packet ra- the placement goal with one exception: i did The second radio, an ICOM 02-AT handdio today with How not leave enough room on [he end of the held, only needs a two-conductor cable. To
To Get Started In timer case to place the jack for an external , use the- HT, the MXC signal from the
FOXBOX is placed in serics with the FIT
Packet Radio. Dave; monitoring speaker. Placing the jack on the - ground
conoectim.
side of the case caused only a minor problem
Ingram, K4TWJ, because the speaker would not be used when
I had originally intendcd to use a third
. , wrote this begin- the FOXBOX was hidden. Careful attention switch in the FOXBOX to accomplish the sener's guide to should allow al] jacks and switches t~ be ries MIC connection for HT use. I decided
packet radio in an placed on the end of the case.
not to use the switch and instead just shorted
the appropriate pins in the interface cable
easy-to-understand manner.It sstarts with
connector. The decision to eliminate the
a nbn-technical description of packet ra- Connectors and Switches
Three external connection jacks and two switch saves the space required to mount the
dio, followed by chapters that include
getting started, setting up your station, swiiches are used for the FOXBOX. For the switch on the case.
networks, BBSs, portable and high-fre- power jack, I chose a conxial power connec- Conclusions
quency operation and even a Packet Ra- tor identical to the one used by my ICOM
Designing and building the FOXBOX was
dio Equipment Survey. There's also an HT. The speaker uses a standard 118-inch quite fun. If the relay keying circuit is countphono jack. I chose to use a 5-pin DIN plug
appendix that includes circuits for inter- for interfacing the radio. Any 4-or-more-pin ed, I achieved my goal of building the dcvice
facing equipment. Join the most excit- jack would have worked well here. The DIN entirely of pans availahlc at any Radio Shack
ing and rapidly growing area of ham plug wa5 the least expensive option explored, store. Furure improvements to the FOXBOX
radio today! Order your copy of H o w To I I wanted the switches to be low-profile could include filters Ior the audio output. AdGet Started I n Packet Radio book for I slide switches. A DPDT switch is required dressing circuitry could be used to allow the
for playbacklrecord selec(iun. An SPDT record and playback of several short mesonly $9.95! (plus $2,00 s&H).
switch is required for power. I used two small sages by the ISD 1000A. The FOXBOX will
DPDT switches because they were easily serve we11 to control many types of hidden
transmitters. If the FOX is to be hidden for a
avaiIabile.
long period of time, provide plenty of battery
P.O. Box 598, Rernond, WA 98073 Operation
capacity for the transmitter. The FOXBOX itOrders Only 1-800-GOT-2-HAM
Operating the FOXBOX is straightfor- self draws only a small amount of power SO
Inquiries (206) 869-8052
ward. Apply 8 to 12 VDC, then put the large batteries are not needed. Creative housplaylrecord switch ( S 2 ) into the RECORD ings tbr the entire FOXBOX package will
CIRCLE 223 ON READER SERVICE C A M
posiiion. Speak at a normal level into the mi- allow limitless hiding possibilities. Let the
Cjif
cmphone to record a message up to approxi- imagination fly.
mately 20 seconds long. The message inlist . ,
nor be long enough to entirely till U3's mem- ' 7 References:,
ory or messase playback may not occur prop- '
I. M ~ l l , . J o s e p hD..KBOV,and Thomns
erly. A t the end o f the message. place S2 N. CurIee WB6UZZ. Tmnsrnirrer Hr~ttring:
back i n the PLAY position. The newly Radio Direcrion Finding SirrtpiJicd. Blue
recordcd message will now play back once at Ridge Summit: Tab Books, 1987, p. 193.
to the
2. Tandy Corporation. ISDIOOOA Voice
the end of every cycle of Timer I .
An interface cable is required bctwecn the Remr.dlPlnyback IC. Fort Worth: Tandy CorFOXBOX and rhc hidden transrnitler. I want poration, 1992.
In Packet Radio
Cort~in~redJmnt
pngr
.
I
1
'The family suggests
that memorial
contributions be made
American
Heart Association ."
When people want to
honor a loved one
and fight heart dlsease.
<
1
HUGE
THE AMERICAN HEART
ASSCKIATION
MEMONAL PR13GRAMs
American Heart
Assocktion
This space prwided as a public service.
O 1%.
50
American Hew AssocialIan
73Amateur Radio Today- March, 1994
I00 PAGE
CATALOG
SLOW SCAN TV
with the Sound Blaster!
BImmrsr C m p a U b l a .ourad ud
Requlnr VGA W x U O - 2 5 B wlv
Portable Receivers
Scatlners
Amateur HF Transceivers
VHF-UHF Transceivers
HT's and Mobiles
Amateur and S W t Antennas
Accessories and Parts
RTTY and FAX Eqt-"- -----'
Books and Manual:
. This cafalog indud
IniversaI Radio
330 Americana Pkwy. 73
neynoldsburg, OH 43068
CIRCLE 187 ON REAl
SERVICE CARD
Say You Saw It In
73 Amateur Radio Today
h!EOh! CALL "SIGHS"
. e * d n e o n ~ r m ~ ~ ~ - n ~ r m
*w-wlrl.k"m
-thUI**.*Llw-Lhm
.wdbmrn.al*IwmSt,
-
- A v r u w a Won m r h w - a h , -.why*
. h p * * r l A . m h r
MWC.
-
-lyuU*-
m y Pu J-.*
r w-m
hdbbu 4,w * E r n d m*
-**erpl*am kb.
Cornplml. c h r n umA. 1 m l l . d and d.llu.nd: SZ25.W.
Mmd4 ~ ~ h p C u r d & m h a h m C s r M O ( I " y . P K ) t W " ~ ~
JUST NEON H. m.WMTVE
-
NM' York 1 W l
(315)792-9032 FAX
d a m n StmL U l l u .
(315)724-919
N.Y. Slorer Re-
AddSelFs Tax