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SENSOR 1 MENU – SENSOR CABLES CALIBRATION
When supplied cables are not long enough to connect a sensor to the SMΩRF, and it is necessary to use longer
cables, the question is how to obtain new calibration data to the Sensor Cables Table. Solution is in this menu,
providing a cables calibration process, which helps you to calibrate new sensor cables yourself by comparing
them to known calibrated reference (supplied) cables without any other tool than your transceiver and a dummy
load.
1
2
CONTROLS:
CURRENT
1.
Sets which cables are used for sampling.
REFERENCE sets supplied, factory calibrated cables matching the Sensor Cables calibration table.
NEW CABLE sets new, custom sensor cables.
2.
FREQ [MHz]
Sets calibration frequency in MHz.
SAVE
3.
Saves newly taken samples and recalculates Sensor Cables Table.
EXIT
4.
Leaves the menu.
Please note, if you leave menu prior saving new values, all taken samples will be lost.
1.
Prepare new cables. Cable type is important, use only good quality, 50Ω coaxial cables. For lengths up
to 10m (33ft) we recommend to use 5-6mm thick cable, avoid thinner cables. Good quality RG58 is fine.
They can be bought from electronics part suppliers (Mouser, Digikey, Farnell) already terminated with
SMA male plugs on each end. If you prefer to make them yourself, make sure to cut them for exactly
same physical length and solder or crimp connectors precisely.
If you need even longer cables, use thick 7-12mm cable, double shielded RG-214 is fine again. As a
termination use SMA female connectors and add short (up to 1,5m) RG58 or RG-174 cable jumpers
terminated with SMA male connectors to each end. Avoid adapters.
Connect sensor to the SMΩRF using supplied, REFERENCE sensor cables. Connect radio to the
2.
sensor and terminate sensor with 50Ω dummy load, rated for 50W power.
Prepare transceiver frequencies and power. On each band set frequency from the Sensor Cables Table,
3.
switch mode to CW and set power to 50W. If you cannot set 50W power, use any lower, maximum
available power. Once you set frequencies and power, do not touch frequency and power setting knobs
anymore.
On screen set CURRENT cables to REFERENCE. [1]
4.
5.
On screen set frequency [2] and switch the radio to this band. Verify that the frequency on the screen and
the radio match.
6.
Key the radio, let output power to stabilize for a second and push the MENU button to take a sample.
You should see captured levels in the table, REFERENCE row.
7.
Unkey radio and return to the point 5, until after you sampled all bands.
Replace reference sensor cables for new cables. Keep reference cables together with matching
8.
certificates on a safe place. You will need them whenever you will want to recalibrate or replace your
custom cables.
microHAM © 2015 All rights reserved
CALIBRATION PROCEDURE:
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