Table of Contents

Cornell ARC Meeting 2012-2-16


High Frequency Presentation

Kevin gave an overview of working HF bands. I have included some notes from his presentation. (Thanks Kevin!)


Always disconnect the antennas and power source when you are not using it. Not really important during snow season, but during rainy seasons lightning can take out our antennas. We have decent dummy loads to prevent this, but lightning is mean and we prefer to be safe.

TS 2000s (the power supply - 12 Volts). The driver transistors will fail, and they are very hard to replace. If they burn out we will no longer be able to transmit on 6m. One theory has to do with the standard amateur equipment creates spikes. To address this issue turn the power supply on before hooking up the power supply to the transmitter.

Remember when transmitting to check the band plans. Technicians have very restricted access to HF (though there are some bands). Generals have acces to a good portion of the bands, however.


We are near the peak of a minimal sunspot cycle - more information here. In short, more sunspots means more radiation, which ionizes the atmosphere and widens the D, E, and F ion layers. The ion layers bend signals back to the earth. Wider layers means greater bending, higher frequency means less bending. Between any two points on Earth there is a frequency (called the Maximum Usable Frequency) that is the highest frequency that will still bend back down.

Currently 10 meters is on the edge of good propagation during the day. The best times for long distant propagation are in the morning and the evening, as you will hear Europe/Asia but not the States. At those times 20 meters is about the MUF.

The distance is proportional to frequency. To talk twice as far double your frequency. If you don't hear anyone, try calling CQ for a while because someone might be listening. Around 28100 there are beacon stations. They send a callsign followed by /b (Dah-dih-dih-dah-dit Dah-dih-dih-dit).


Before transmitting listen for a while. If you hear someone tune up until you don't hear any interference and listen again. If you don't hear anyone try calling “CQ” a couple times. However, there are skip zones that keep moving during the day. Be prepared to accommodate new people as they might have been talking for a while already. If someone is calling “CQ” respond <their callsign> <your callsign>. There will often be roundtable conversations that flow in a ring-type pattern.

The Tuner

Listens for frequency and it has a (4000+) memory as well. When you key up a new frequency it will loop through a bunch of capacitor/inductor combinations. To help the auto-tuner give it a steady carrier around 5-10 watts. To do this, change to FM mode, set power to 5 watts, key up (but don't talk) and wait for the tuner to tune itself. After a brief time it will converge, stop switching stuff out, and display the SWR/Power meters. There are two antennas - press the ANT button to switch which antenna it is using (right/left).

The Transmitter

The ANT1/ANT2 are for HF (up to around 6 meters). The VHF connector is on the top right of the back of the transmitter - you don't need the tuner hooked up for the VHF antenna but you will definitely need it for the HF antennas. There is some color coded marks to help you connect the cables up. There is a Kenwood manual that should be kept next to the transmitter at all times - it is very useful! A quick note on squelch control - it does not work well on SSB; you want to set it low so it doesn't end up quieting your actual signal.

On SSB you can adjust the frequencies you will listen to. The transmitter can be set to 5000 hertz bandwidth, but it can't actually handle that wide a band very well. You don't want a wide band either, because you will pick up noise. Around 2600-2800 Hz should be good.


There is a satellite (information here) that flies by about once a day. It listens around 435.250 and repeats (while flipping the signal to prevent Doppler effects) on 145.900.


There will be a fox-hunt this Saturday


Coordination on repeater this Sunday for fox-hunting. There will be discussion on the 61 (146.61 kHz, -500 offset, 103.5 PL tone) this Saturday to coordinate rides with some experienced hunters. Kevin will be in the Phillips parking lot at 10 AM.