630 Meters for 2020

Project 3 of 7 for 2020

Upgrading from last year’s 630 meter station is underway. The antenna will be reused. A new station transceiver was added during the year and can provide the 630m signals on the XVTR port. The biggest addition will be a linear amplifier to improve the transmitted signal. Actually, it’s a non-linear amplifier because the WSJT-X digital modes do not require the amp to be linear. A non-linear amp is just fine. The amp decided on is the K5DNL. http://k5dnl.com/sale_amp200.htm

Two Hundred Watts? Yes, it’s legal because with a 2.5% efficient antenna the radiated power is a perfectly legal 5 watts.

On 630 meters, or 474.2 KHz, the antenna’s phase is very important. The rf current and voltage need to be in the same phase for the best radiation. An oscilloscope is used to make the phase measurement, with current on one channel and voltage on the other. When the sine waves line up the phase is perfect. K5DNL has available the hardware to sample the current and voltage to feed to the scope. Ken calls it the Scopematch. One was obtained along with the amplifier for this project. The scope in the shack here is the Hantek DSO5102P dual channel oscilloscope.

A big jump ahead happened when the decision was made to reconfigure batteries and build a 24 volt system temporarily. The amp runs on 24 volts. The main batteries for the permanent 24v system are on order but are still off shore.

Status: A temporary 24 volt supply has been set up and the project is awaiting time to complete it.

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