hupRF PAT Manual de usuario
hupRF © 2016
PAT Install 718 10 Sept 2016
hupRF Panoramic Adaptor Installation – IC718
These instruction cover installation of the PAT board in the 1st IF of the ICOM IC718 –
64.455MHz – this gives access to all receiver options on the main receiver.
Although the rig uses separate mixers in the Rx and Tx paths, the 1st IF filter (FL301B) is
common to both directions. The connections shown here pick up the output of the filter after
the diode switch, so significant Tx signal should not be present. However, it is recommended
that PAT is powered from the R8V line, which will automatically mute it on transmit.
Basic instructions are given for installing the PAT as an IF Panoramic Adaptor Tap – used in this
mode your SDR must be tuned to the 1st IF of the radio, and then your display will track the
tuning of your rig – however, the displayed frequency will be that of the IF, not the radio.
Because the connection point on the IC718 is after the IF filter, the bandwidth available to
display is restricted by the filter.
In the block diagram to the left, the PAT
input signal will be picked up just before
D401, the second mixer.
There are no convenient test points
provided by ICOM, so the signal and
power must be picked up directly from the
Main circuit PCB.
The PAT output can be brought out by
either a socket mounted in one of the
ventilation slots of the rear panel, or by a
flying lead with a free plug on the end –
this latter method is easier.
The circuit diagram to the left shows the
pick up point for the PAT input and the
connection point for the Vcc power,
taken from the R8V line. In practice,
this measures about 6.9V on Rx and 0V
on Tx.
hupRF © 2016
PAT Install 718 10 Sept 2016
1Build and test the PAT kit – use a 9v supply and you should measure a gain of
approx 1dB at 70MHz.
2Remove top, bottom and inside top covers from the IC718
3As stated above, the output can either be by a socket mounted in the vent slot or by
a flying lead. The pictures below show the mounting of a socket in the vent slot –
this is quite fiddly, but saves any drilling of the panel.
Fig 1 – position of SMA connector on rear panel
4The PAT board can be located on a screening can as indicated on the PCB diagram
below. This also shows the two connection point to the circuit. Make sure that the
Input end of the PAT is to the right in this diagram to keep the lead short.
hupRF © 2016
PAT Install 718 10 Sept 2016
5The PAT board is held in place by double sided tape, so can easily be removed
should it become necessary for any adjustment of the cores below it.
Fig 2 – Location of PAT inside IC718
6The connection points on the PCB can be accessed without removal of the PCB, but a
fine tipped iron will be required to reach the small pads that must be soldered to.
The black wire in Fig 3 is the PAT input signal, whilst the red wire in Fig 4 is the power,
taken from the R8V line.
Fig 3 – PAT input connection
hupRF © 2016
PAT Install 718 10 Sept 2016
Fig 4 – PAT power connection
7It is easier to pas the RG178 cable through to the output if the two TMP connections at
the rear of the Filter PCB (top side) are temporarily removed. Don’t forget to replace
them!
8The output connection from PAT to the rear panel will need approx 100mm of RG178A
miniature coax. If the PAT is mounted as shown in the pictures, the path is quite short
and direct. If you use a flying lead output, it is recommended that you use a small cable
tie to secure the lead as it exits the rear panel – this avoids any stress on the
connections.
Fig 5 – PAT output connection
hupRF © 2016
PAT Install 718 10 Sept 2016
9 Dimensions for preparing the ends of the cables are given in Table 1 and Fig 9. Do not
pigtail the ends of the coax, but make them off as in Fig 2. See also details at the end of
this note.
Fig 6 – RG178 output lead terminated on the SMA socket
10 Replace the covers, and test with your SDR
Terminating PTFE Coax cables
These instructions could be used, with suitable modification, to correctly terminate any of the
PTFE coax cables, such as RG142, RG178, RG188, RG196, RG316, etc. The termination method
ensures good quality RF connections up to higher microwave frequencies
•Using a scalpel, cut the sheath back at the required length.
•With a hot iron, tin the exposed braid fully.
•With the scalpel, score around the point where the braid must end.
•Use long-nose pliers to bend the end of the coax outside the score line – the braid will
crack on the score line and the excess can be slid off the dielectric.
•Strip the dielectric to reveal the inner.
Fig 7 shows a prepared ned of the RG178 cable ready for installing in the IC718; other examples
may be seen in the other instruction sheets posted.
hupRF © 2016
PAT Install 718 10 Sept 2016
Fig 7 –RG178 cable prepared for terminating
Table 1 below shows the measurements recommended for the cable end preparation for the
IC756 installation and Fig 7 below gives further clarification.
Cable
IC718Connection
Sheath
Braid
Dielectric
Inner
Output
PAT
9mm
3.5mm
2mm
3.5mm
Output
SMA
9mm
3.5mm
2mm
3.5mm
Table 1 – Cable stripping details for IC718 installation
Fig 7 – Cable termination preparation details
Extracts from the ICOM IC718 Service Manual are acknowledged as the copyright of the ICOM
Corporation.
Tabla de contenidos
