PreciseRF HG3 User manual

HG3 Loop antenna connections and trouble shooting
7/3/20 v2
If, after installing your HG3 loop, you are not receiving any signals or are having tuning difficulties,
make sure you have read the user guide and watched the demo video. 90% of all problems are the
result of not having the correct connections, bad or intermittent cables, cables not completely seated, or
not understanding the radio or controller controls.
1. Make sure the radio is receiving correctly
a) Set your radio to a 40m frequency, such as 7.15 MHz and select the SSB mode.
b) Connect a known good antenna (a length of 10’ piece of wire will also work) to the radio’s RF
input.
c) You should note an increase in the background static. This indicates that the radio is receiving
something and most likely working correctly.
2. Check for proper tuner and controller function
a) See the figure at right.
For this test, you do
not need to assemble
the HG3 in its
operating
configuration. We’ll
just use the controller
and the tuner (the light
gray case).
b) Connect the CAT6
cable from the
controller output (labeled TUNE) to the tuner’s CAT6 input. This cable must be pushed in
completely and securely seated.
c) Carefully remove the tuner’s cover (4 bolts secure it in place). DO NOT TOUCH THE
CAPACITOR PLATES.
d) Apply power to the controller and turn it on. You should notice that the green MOTOR LED
illuminates as the cap is indexed to 40m. If the cap is already at 40m, not much cap turning will
be observed.
e) Using the BAND F1 button and <- -> buttons, change the band from 40m to 20m, then back to
40m. You should notice the capacitor is opening and closing accordingly (at 40m it is mostly
closed).
f) If the capacitor is not opening or closing as the band is changed, then the controller, CAT6
cable, CAT6 connectors, a loose or incorrect connection, the tuner, or the tuner driver may be
the cause.
g) Check that the tuning capacitor is not shorted. Connect an ohm meter across the tuner input
connectors (located on the sides of the case) while tuning from 40m through 10m. There should
NOT be any DC shorts while doing so. If shorted, it must be returned for warranty service.
h) Using your ohm meter, make sure that the capacitor connections are properly soldered.
i) Re-install the cover.

3. Check that all the loop connections are good
a) Refer to the figure at
right. Assemble the
HG3 loop and connect
the radiation loop
(LMR600) to the
tuner’s HF connectors.
Ensure they are
securely fastened to
the tuner HF inputs
located on each side.
b) Connect a known
good 50 ohm BNC
cable from the copper
induction loop to the
radio’s RF input. (they
could be intermittent,
so jiggle them to check
them).
c) You should notice an
increase in the
background static.
This indicates the connections from the radio to the induction loop are good.
d) If you don not hear an increase in the background static, then any of the following may be bad:
Cable/connector, induction loop, radiation loop or the tuner.
e) To check the induction loop, use an ohm meter and check that it reads a DC short at the BNC
input (it is just a one turn copper loop). If it is open, the induction loop is defective. Use an ohm
meter to check the cables and all connectors.
4. Check the HG3 EXPRESS for proper operation
a) Make sure you have completed all the checks in 1, 2, 3 above.
b) Refer to the figure at
right. Assemble the
HG3 loop and connect
the radiation loop
(LMR600) to the
tuner’s HF connectors.
Ensure they are
securely fastened to
the tuner HF inputs
located on each side.
c) Connect the CAT6
cable from the
controller output
(labeled TUNE) to the
tuner’s CAT6 input.
This cable must be
pushed in completely
and securely seated.

d) Ensure that the copper induction loop is connected to the radio’s RF input/output connector.
e) For this test, set the radio to 40m (7.15MHz will work).
f) Turn the controller from OFF to ON (this indexes the tuner to 40m).
g) You should notice an increase in the background static. This indicates that the connections from
the radio to the antenna’s induction loop are good.
h) Using the controller’s tuning knob, adjust it for the loudest static. This indicates the HG3 loop is
working properly.
5. Check the HG3 PRO for proper operation
a) Make sure you have completed all the checks in 1, 2, 3 above and you have the USB PRO key
installed.
b) Refer to the figure at
right.
c) Assemble the HG3
loop and connect the
radiation loop
(LMR600) to the
tuner’s HF connectors.
Ensure they are
securely fastened to
the tuner HF inputs
located on each side.
d) Connect a known
good 50ohm BNC
cable from the copper
induction loop
(mounted on the
antenna) to the
controller’s BNC ANT
input.
e) Connect another
known good 50ohm BNC cable from the controller’s XMTR to the radio’s RF input/output.
f) Connect the CAT6 cable from the controller output (labeled TUNE) to the tuner’s CAT6 input.
This cable must be pushed in completely and securely seated.
g) Set the radio to 40m (7.15MHz will work).
h) For this test, turn the controller from OFF to ON (this indexes the controller to 40m).
i) You should notice an increase in the background static. This indicates that the connections from
the radio to the induction loop are good. If you do not get an increase in noise, the coupler
board, mounted to the controller main board, may be the cause.
j) Select a frequency on the 40m band (7.15Mz will work).
k) Press AUTO (F2) for auto-assist. The LCD prompts “Connect Radio Transmit 1-3 Watt CW”.
l) Transmit a low power carrier of about 2-3 Watt and press OK. If the power is not correct, it
prompts to adjust the power level accordingly. After finding an acceptable SWR, auto-tuning
ends. This indicates the loop is working properly.
If, after completing all these checks, you are still experiencing difficulty, contact preciseRF for
further technical support and or warranty service.
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