NOTES ON THE INDEX LABS QRP PLUS TRANSCEIVER
After using the new QRP++ and Companion tuner since February, here are some
notes and mods. I have been using the QRP++ and Companion mostly from hotel
rooms on business trips. Antenna setups have been fair to miserable.
When receiving CW with the bandwidth set tighter than about 1.4 Khz, strong
adjacent signals in the IF passband swamp out the desired signal. It sounds
like a extremely strong, noisy CW signal. Setting the SCAF filter to 2.4
Khz position helps but then you have minimum selectivity. I tried the RF
gain mod suggested by Bruce. It helps some, but not much.
The SSB transmit audio is excellent. I've gotten very good reports on the
audio even on 75 Meters. My mike is a generic electret mounted in a surplus
I attached a switch to a small cable with a plug into the key jack to use
as a "tune" button.
The noise bridge in the Companion takes getting used to but it appears to
The tuner circuit has worked on both twinlead and coax type feeds. I've
used small resonant loops, a 60 ft., 30 ga. wire, and a coax fed, 20 meter
dipole. I also use 2 - 16 ft. or 1 - 33 ft. radial on the tuner ground lug.
The Companion has no ON/OFF switch or fuse between the battery, the noise
bridge and the radio cable. Once after being stored for a couple of weeks
without charging, the battery died while I was trying to check into a net.
The noise bridge had drained down the battery. The cable to the radio,
being hot all the time, also arced on the radio connector while trying to
plug it in.
After this happened several times, I decided to do a field modification to
the Companion. I added an Airpax 4.0 amp circuit breaker between the
battery and the noise bridge and radio power cable. I got this breaker at a
hamfest but Ten-Tec has used this same type of breaker on their HF rigs. It
mounts in a 5/8" hole and looks like a toggle switch on the outside. I
opened up the tuner case, unsoldered, and removed the cable for the wall
cube charger from the power supply board. I mounted a coaxial socket (Radio
Shack) on the upper right rear of the tuner (to the right of the GND
binding post) and wired it to the power supply board. A coaxial plug (Radio
Shack) attached to the end of the cable completed the new wiring for the
wall cube charger. I removed the strain relief grommet from the original
hole for the charger cable, enlarged it to 5/8 ", and mounted the circuit
breaker. The circuit breaker is an exact fit for the available space so go
carefully if you try to duplicate this. From the rear, on the left side of
the tuner the circuit breaker is at the bottom, next up is the cable for
the radio, then the two SO-239s for the tuner. It is not shown in the
schematic but the power supply board has a blocking diode on it to prevent
discharging the battery. (Unplug the battery connector first) I removed the
noise bridge and the radio cable positive leads from the power supply
positive terminal post and attached them to the "load" terminal of the
breaker. I ran a new wire from the other breaker terminal back up to the
power supply positive terminal post to complete the circuit. Now the
circuit breaker provides protection and switching for the noise bridge and
radio power. The battery can be charged whether the breaker is on or off by
plugging in the charger cable. I may also be able to use the new charger
connection to supply power from a solar panel to charge the battery.
I'm working on some kind of padded box to put all the radio stuff in that
will survive air travel.
So far, in the airport security lines I've had to unpack the radio gear to
get down to the laptop PC to turn it on but no one has even commented on
the radio, tuner, keyer, wires, and other stuff.
73 - Dave, N4ELM.
My thanks to Dave N4ELM for allowing me use his file on my web site - G3YCC.
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