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Icom IC-7300, Manual

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Icom IC-7300 Manual Download Page 31

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WHY ? I set the radio to punch out 800 watts and 
the ham across the valley can hear me !

D. Michaels  N1RF   Jan 10, 2017

Transmitter Monitoring

2

N1FD.org   TECH  NIGHT   Jan  10,  20117
Transmitter  Monitoring

Technician License Test:

Section T7B (2014): Common 

transmitter and receiver 

problems:  

symptoms of overload 

and overdrive; distortion; causes 

of interference

Summary of Contents for IC-7300

Page 1: ...GETTING THE MOST FROM YOUR HF TRANSCEIVER FRED KEMMERER AB1OC JANUARY 10TH 2017...

Page 2: ...Topics 2 Not to Scale Its mostly about the receiver Transmitter amplifier operation tips and tricks Common operating scenarios...

Page 3: ...Attenuator Notch Filters Noise Reduction Blanker Passband Tuning DSP Filter IF Shift Pan Adapter Spectrum Scope Its Mostly About The Receiver Commonly Available Controls Multi Function Screen Access...

Page 4: ...lters Dynamic Range the difference between the loudest and the weakest signal you rig can handle Want to maximize Dynamic Range for the target signal Mostly about adjusting for optimum RF gain and ope...

Page 5: ...Filters limit Bandwidth to reject unwanted signals preventing them from adversely effecting performance The Automatic Gain Control AGC System attempts to maximize Dynamic Range within Weak Signal Rec...

Page 6: ...lly AGC System must maximize A D converter resolution for the desired signal Many possible sources of non linearity are eliminated A D Converter Resolution and Oscillator Phase Noise become the main p...

Page 7: ...acent signal rejection RF Gain Control Preamp Attenuator and AGC Time Constant settings optimize Dynamic Range Adaptive Noise Filtering is used to reduce noise improving S N Ratio RF Gain Adjusts ed I...

Page 8: ...ters 8 Not to Scale Minimize Noise BW Interference Roofing Filters typically fixed BW filters applied before IF stages DSP filters Digital Signal Processing after IF stages Both are realized in Digita...

Page 9: ...ostly About The Receiver CW Reverse Sideband CW R 9 Not to Scale CW R Sideband VFO Freq Standard CW Sideband Desired Signal Interference VFO Freq Reversing CW Sideband to Improve Adjacent Signal Rejec...

Page 10: ...ntrol 10 A D Digital Proc FPGA RF Pre Amplifier Bandpass Filter D A Digital Osc AGC Loop IP A D Range 00 0 11 1 Too Little Base Gain Preamp Helps A D Range 00 0 11 1 Optimal Base Gain A D Range 00 0 1...

Page 11: ...ntrols to use Preamplifier Attenuator base setting to get in the ball park AGC Time Constant set to match characteristics of the desired signal RF Gain Control manual adjustment to fine tune AGC opera...

Page 12: ...tion Digital Magic to Reduce Noise 12 Adaptive digital filter estimates random noise characteristics to cancel Detects pulse oriented noise and eliminates using short duration blanking Use these spari...

Page 13: ...matched to mode Fast for CW mode Medium for Digital modes Slow for Voice modes SSB AM Roofing DSP filter s matched to mode no IF shift 2 4 3 0 KHz for Voice or digital pass band modes 500 Hz for RTTY...

Page 14: ...crease noise reduction levels and settings 5 As you do steps 1 4 pay attention to desired signal intelligibility not levels of signals and noise 6 Try manual RF gain control be careful especially if w...

Page 15: ...W or Digital Modes Manual Notch Filter Very useful for birdie elimination Don t forget to turn it off when before you move to a new frequency CW Auto Tune handy for zero beating but you should also le...

Page 16: ...avorite watering holes quickly ex digital sub band Good idea to set these up for 60m operation two sets CW and SSB Return to recent frequency programmed scans repeaters Receive Equalizer Settings Menu...

Page 17: ...TRANSMITTER TIPS AND TRICKS 17...

Page 18: ...Meters 18 S0 Receive Signal Strength Po Output Power SWR Displays Antenna s SWR when in Tx ALC Automatic Level Control Limits COMP Speech Compression Level VD Final Amp Drain Voltage ID Final Amp Drai...

Page 19: ...ing Adjusts Tx Pwr Mic Gain VOX CW Break in Your Transmitter Important Controls Multi Function Screen Access Function Screen Tx Incremental Tuning Auto Tuner Manual Tx Operating Mode Split Controls Tx...

Page 20: ...tion in a lightly filled band Set ALC so that you have 50 deflection on the peaks of your audio Test with close in speech to microphone and a little louder than normal Its OK to use a modest amount of...

Page 21: ...isp easy to copy audio for DX ing and Contesting Ask someone who has good audio on the air to help you with setup VOX Can use in quite conditions and adjust properly for you mic and environment Don t...

Page 22: ...you must tune up on the air do it at low power and off the operating frequency of others If you rig has automatic antenna switching configure it to put you on your best antenna for each band Your sta...

Page 23: ...a dummy load and use it to adjust your amplifier before going on the air Learn to quickly fine tune on the air and do it it off the operating frequency of others In all cases your station should be c...

Page 24: ...COMMON OPERATING SCENARIOS 24...

Page 25: ...B up 5 or up 5 to 10 Listening up 5 KHz or in a range starting there Strategies for working a split station Set you receiver to the DX s Tx frequency enable split and use XFC or a second receiver to t...

Page 26: ...atches Tx and Rx VFO Listen on Adjust Secondary Tx VFO 1 Tune to DX Transmit Frequency 2 Enable split mode 3 Set Tx and Rx VFOs to same frequency 4 Hold XFC and adjust secondary VFO to where the DX is...

Page 27: ...t time Avoid calling out of turn don t be QRM Don t use partial callsigns Ops trying to maximize their rates won t work you Wait enough time for most of callers to stop Try calling with a slightly dif...

Page 28: ...u see ALC meter deflection Be mindful of power levels when operating in shared passband modes like PSK or JT65 If not you ll be the strong close in interferer that everyone dislikes Use noise reductio...

Page 29: ...Getting To Know You 29 Reading The Manual Reading The Fine Manual For Your Rig...

Page 30: ...ch out 800 watts and the ham across the valley can hear me D Michaels N1RF Jan 10 2017 Transmitter Monitoring 1 N1FD org TECH NIGHT Jan 10 20117 Transmitter Monitoring Yep and the next door neighbors...

Page 31: ...can hear me D Michaels N1RF Jan 10 2017 Transmitter Monitoring 2 N1FD org TECH NIGHT Jan 10 20117 Transmitter Monitoring Technician License Test Section T7B 2014 Common transmitter and receiver probl...

Page 32: ...er Monitoring Devices in the Radio Shack D Michaels N1RF Jan 10 2017 Transmitter Monitoring 3 YOU Radio analog digital meters Stand alone power SWR meter Oscilloscope with RF sampler Dedicated Station...

Page 33: ...D Michaels N1RF Jan 10 2017 Transmitter Monitoring 4 Transmitter Monitoring Devices in the Radio Shack...

Page 34: ...es Is Your Power Meter Accurate D Michaels N1RF Jan 10 2017 Transmitter Monitoring 5 Oscilloscope with RF sampler Oscilloscopes can provide an adequate calibration of the power setting on your radio a...

Page 35: ...an 10 2017 Transmitter Monitoring 6 Transmitter Monitoring Devices Is Your Power Meter Accurate RF Sampler RF Sampler RF Sampler takes a very small percentage of the Tx power that can safely be sent t...

Page 36: ...nsmitter Monitoring 7 Current Transformer RF Sampler Resistor Divider RF Sampler Typical sampling power values are 1 100 20 dB 1 1000 30 dB 1 10 000 40 dB 1 100 000 50 dB Transmitter Monitoring Device...

Page 37: ...ransmitter Monitoring 8 Io Io sqrt Tx power 50 Is Io N I1 Is Rser Rsa sum Rj I2 Is Rsh sum Rj Io Is I1 I2 Simplification To maintain impedance balance and reduce required N for a given dB Rsh Rser 50...

Page 38: ...D Michaels N1RF Jan 10 2017 Transmitter Monitoring 9 Design for Current Transformer RF Sampler...

Page 39: ...Testing the 50 dB RF Sampler D Michaels N1RF Jan 10 2017 Transmitter Monitoring 10 Scope Chn 1 56 v p p Chn 2 0 180 v p p dB 49 8...

Page 40: ...ull Station Monitor D Michaels N1RF Jan 10 2017 Transmitter Monitoring 11 Frequency Counter Power avg peak PEP SWR Waveforms CW SSB AM FM Digital Keying envelope AM Modulation distortion SSB 2 Tone Te...

Page 41: ...D Michaels N1RF Jan 10 2017 Transmitter Monitoring 12 Digging Deeper with a Full Station Monitor...

Page 42: ...Digging Deeper with a Full Station Monitor D Michaels N1RF Jan 10 2017 Transmitter Monitoring 13...

Page 43: ...ransmitter Power with the Oscilloscope http preciserf com wp content uploads 2012 04 Appnote 4 Power tests1 pdf Build a Quality RF Sampler by Don Jackson W5QN www collinsradio org wp content Build a Q...

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