Get more TX audio from your IC-718. Look below...
Station Location - Single story apartment
Radio 1 : Icom IC-718
Headset : Heil Proset IC
Tuner : MFJ-901B 200W tuner
Antennas: Ground mounted vertical.Tunes & works 80M - 10M. Antenna is 15 feet high top loaded with ground screen and tuned radials.
Digital modes: PSK-31 (20-60 watts) 80M-10M, JT65 (10-40 watts) 80M-10M, SignaLink USB interface
JT9 (15 watts) 20M just started using this mode 4/28/2013, use WSJT-X for this mode along side (JT-Alert forWSJT-X)
See where your digital signal is being heard http://www.pskreporter.info
THIS ANTENNA HAS BEEN DISMANTLED AND NOT IN USE, IT HAS BEEN REPLACED WITH A WIRE VERTICAL
Center loaded vertical (better efficiency than base loading) 14' 80-10M with capacitance hat, helps distribute RF current along more antenna. Still a compromise antenna but works better than nothing. The center loading coil is used to resonate the antenna on 10M - 80M. It is a home made coil made of 50' #12 AWG copper wire round 4.5" OD 5" length. The ground plane is aluminum screen and 2 wire radials. The coax choke sitting on the ground keeps the RF at the antenna and not on the coax. All PVC is SCH 40 1" tube. Everything to make this antenna was purchased from LOWES except the coax and the SO-239. The wire is 16 AWG. The antenna has worked across the US on 80M JT-65 and into Europe on 40M. The small rod mounted half way is switched in to match the antenna on the higher bands.
The antenna in action on 80M JT65 running 50 watts
Icom IC-718 TX audio mod, resistor value to be replaced is very close to the value used in the IC-756PROIII mic amp circuit giving it more gain. The capacitor in parallel with R2211 in the IC-756PROIII mic amp circuit is a 100pF and not a 470pF as in the IC-718. May have slightly different TX audio characteristics than the 756PROIII if not changed. Schematic below is from the IC-718 service manual which can be downloaded by googling it.
This mod will give you all the modulation you need to kickup a little better average SSB signal on TX.
The surface mount resistor to be completely removed. Not an easy task. 1/4 W resistors shown for size comparison.
Other audio improvements: Icom HM-36 Chinese made microphone mods:
Replace the 22K resistor on the PCB of the mic with a 2.2K resistor which it should have been in the first place. The Chinese made HM-36 mics have the wrong value installed.
Homemade loading coils - Same coil used on antenna above
1218170 Last modified: 2014-08-27 17:49:16, 6669 bytes
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