Embed Size (px)
Citation preview
November, 2014
Many all band mobile rigs do not have cross band repeat
capabilities.
This is an example of how to implement a cross band
system for the IC-7000
o Uses a Baofeng UV-5R to interface with the IC-7000
o Three modes of operation possible
• Listen to repeater output remotely
• Standard cross band
• Full mobile repeater – requires two HT’s
Note: This works just fine with my rig. However, I am not
responsible for any smoke released from your equipment should
you choose to try this project. Attempt at your own risk.
Sometimes conditions don’t allow reliable repeater access
with a handheld.
o Too far from repeater
o Obstructions (in a building, behind a hill)
Being confined to a truck or setting up a portable station
can be problematic.
Cross band repeating combines the portability of a
handheld with the capability of a mobile station.
Many HF mobile rigs do not have cross band repeat
capabilities.
This example applies to the IC-7000. Probably
compatible with other Icom rigs using the 13 pin
DIN accessory port.
o Likely works with IC-706 rigs without modification
o Should work with most rigs. Just check ACC pin outs
Mobile Rig
Operating on VHF
repeater pair
UHF
Wired
Interface
VHF
Repeater
Remote handheld transmits on UHF
Handheld in vehicle receives signal
o opens squelch, output to speaker
o This output is used for the keying circuit and to pass audio to the IC-
7000
o Closes squelch when signal ends
IC-7000
o Keyed
o Transmits audio to the repeater on the VHF input frequency
o Un-keyed
IC-7000 receives a signal from the repeater
o Squelch opens, audio received
• Use this to key the local handheld
• Audio passed to the local handheld
o Squelch closes
• Un-key handheld
Local Handheld (UHF)
o Keyed
o Transmits audio
o Un-keyed
To make IC-7000 transmit
- Pin 2 (GROUND)
- Pin 7 (KEYING)
- Pin 11 (Audio In)
To make handheld transmit
- Pin 2 (Ground)
- Pin 12 (Audio Out)
- Pin 13 (Squelch Signal)
SPK-
PTT SPK+
MIC-
PTT
MIC+ - SPK+ to SPK- has a 3.5V DC offset
voltage when squelch opens
- Can be used to key IC-7000
using a simple NPN transistor
circuit
- Not present on Baofeng although
they use the same mic.
- To key the Baofeng, close the circuit
between MIC- and SPK-/PTT.
- Triggered by squelch on IC-7000
This connection is common to multiple radios.
However, this system will only work when the
3.5 V offset voltage is present during receive.
It is not present on Wouxun radios.
SPK- / PTT
1k Ohm
SPK+
3.5 V
Pin 7 - Key
Pin 11 – Audio In
.005 micro F
Pin 2 - Ground
Pin 12 – Audio Out MIC+
MIC-/PTT Pin 13 – Squelch
Grounds on open
~10k Ohm
NPN Transistor
2N2222
or equivalent
SPK- / PTT
Cable 1
2.5 mm
Cable 2
2.5 mm
2nd UV5R
(Optional)
Cable 3
3.5 mm
DIN 13 CABLE
The NPN transistor circuit is used to key the mobile rig.
When the transistor sees voltage from the speaker it
grounds Pin 7.
The .005 micro F capacitor is used to increase highs in
transmit audio. The audio out of the Baofeng speaker port
had too much bass without the capacitor. You can play with
capacitor values to fine tune audio to your preference.
The 10k Ohm resistor reduces the audio level from the Icom
receiver. Without this the audio was “hot” and garbled.
Mobile Rig
Operating on VHF
repeater pair
UHF Cable 1
VHF
DIN 13
- Handheld acts only as
a receiver
- Not required to wait for
repeater to drop
Mobile Rig
Operating on VHF
repeater pair
UHF
Cable 1
Cable 2
VHF
DIN 13
- Required to wait for
repeater to drop before
transmitting
Mobile Rig
Operating on VHF
repeater pair
UHF Cable 1
VHF
DIN 13
- Handheld 1 operates as a receiver on
1 UHF frequency
- Handheld 2 transmits repeater audio
on a second UHF frequency
- Need separation to avoid
interference between 2 UHF
handhelds (frequency separation,
distance between antennas)
Cable 2
Cable 3
DIN 13 Cable o $12 Buxcom
Circuit Board (1.75x1.75”) – makes 2 o $2.50
Project Enclosure (4x2x1”) o $4.00
Transistor, capacitor, and resistors o 1 k Ohm, 10 k Ohm, 2N2222, .001 micro F
o $3.00
2.5 mm stereo cable (2 male ends) o $3.00
3.5 mm stereo cable (2 male ends) o $3.00
Baofeng UV-R o $35.00 each
Soldering iron and solder
Multi-meter
Shrink tube or electrical tape
Drill and drill bits
Screw driver
Radio Shack
Model: 276-148
Radio Shack
Model: 270-1802
< $30 for interface materials
Break the circuit board in half.
Sand/cut the sides so that it will fit in the enclosure.
o Slot holes so that it can be mounted in the base of the enclosure.
Cut the 3.5 and 2.5 mm cables in half
o Remove 2.5 - 3” of outer insulation, Remove ~.25” insulation from each strand.
o Ohm out to determine wire color for the different plug contacts.
Prepare 13 pin DIN cable.
o Remove 2.5-3” of outer insulation, Remove ~.25” insulation from each strand.
o Ohm out to determine wire colors for pins 2, 7, 11. 12, and 13.
Measure the cable diameter. Drill holes in the box for each cable or add slots to the top so that the board can be taken in and out (what I did).
Run cables through holes (if not using slots).
Mount the components on the side without copper.
o See schematic
Solder in place. The solder should connect the leads and
bond with the copper dot on the board.
Label cables!
Note: I used two 4.7k Ohm resistors in series to obtain 9.4k Ohm.
With power off to the mobile rig, insert the 13 DIN plug.
Mode 1 Test – Remote transmit only (listening to repeater output) o Program the HT to 445.100 MHZ with tone encoding.
• Set the volume control at about 90 degrees from the off position.
o Program the remote HT to 445.100 MHZ with tone transmission (same tone as above). Program the second frequency to the repeater output frequency.
o Connect cable 1
o Turn on the mobile rig and tune to your favorite repeater. Have one of your pals listen.
o Transmit using your mobile rig for a baseline on audio.
o Next transmit using the remote HT. • If audio sounds low … increase HT volume slightly
• If audio sounds hot … decrease HT volume slightly
o Once dialed in … place a mark on the HT base and volume control for future reference.
With power off to the mobile rig, insert the 13 DIN plug.
Mode 2 Test – Cross Band Repeat
o Program the HT to 445.100 MHZ with tone encoding.
• Set the volume control in position (from mode 1 test)
o Program the remote HT to 445.100 MHZ with tone transmission (same tone as above). Connect cable 1 and cable 2.
o Turn on the mobile rig and tune to a repeater in operation.
• Open the squelch (the HT should start transmitting to the remote HT)
• Check audio
• Close the squelch (HT transmission should stop)
o Next transmit using the remote HT.
• Wait until the repeater is clear … call someone.
• NOTE: You must wait until repeater drops to transmit!
With power off to the mobile rig, insert the 13 DIN plug.
Mode 3 Test –Mobile Repeater o Program the HT1 to 445.100 MHZ with tone encoding (receive)
• Set the volume control in position (from mode 1 test)
o Program HT2 to 446.900 MHZ (transmit)
o Connect cable 1 to HT1, and cables 2 and 3 to HT 2
o Program the remote HT to 446.900 MHZ with tone transmission (same tone as above). Set the offset to -1.8 MHZ • The 2 HT’s act as a repeater system with reception on 445.1 and transmit
on 446.9.
o Turn on the mobile rig and tune to a repeater in operation. • Open the squelch (the HT2 should start transmitting to the remote HT)
• Close the squelch (HT transmission should stop)
o Next transmit using the remote HT. • The transmission should be routed through HT1.
Mount the circuit board in the base of the box
Position cables and lock in place (I used tape to wrap the cables).
Consider adding chokes to each cable.
Install the cover and enjoy your accomplishment!
Usage o Take care not to interfere with repeater operation. Monitor while using
and shut down if there are issues. Never leave unattended. • Local noise causes HT squelch to break – keys repeater
• Dead battery will cause HT to cycle on and off – keys repeater
o Use tone encoding
o Check local frequencies to make sure you are not interfering with other stations.
o Use low power setting (1 W) when possible.
o Consider using a battery eliminator if using for long periods.
