Our goal for this phase of our EME Station Project is to get our new tower up, install the Azimuth Rotator and Mast, and run the hardline and coax cables for our antennas from the shack to our new …
We got our new 26 ft EME tower up this past week. The new tower is a hybrid free-standing/guyed design and will support our planned 2M EME Antenna System.
Install the phase-tuned coax cables and hardline coax that will connect our antennas to the rest of our station
Connecting the coax cables and hardlines to an expanded station ground block at the entry to our shack
You can read all about this phase of our project via the link above. The next phase of our project will include running control cables and installing a control cable junction box on the tower, hooking up and testing the rotator, completing our grounding and bonding system, and preparing to install the antennas and tower electronics when they arrive from M2 Antenna Systems.
Our new 2M EME station will have Adaptive Polarity capability via MAP65. MAP65 requires that received signals from the Horizontal and Vertical planes of our antennas arrive at the receivers in our shack precisely in phase with each other. We used a VNA to precisely measure coax cable length…
We are continuing to make progress on our new 2M EME Station. The MAP65 adaptive polarity aspect of our plans requires that the phase relationship between the Horizontal and Vertical elements of our antennas be precisely maintained by our receive coax cables.
The construction of these coax cables required us to use a Vector Network Analyzer (VNA) to precisely measure and equalize the electrical lengths of our receive-coax cables. We know that a 1/4 wavelength section of coax cable which has an open-circuit at one end will appear as a low (resonant) impedance at the opposite end. If we use a VNA to precisely measure the minium resonant frequency of our coax cables in this way, we can use a simple formula to determine the cables’ lengths.
The article associated with the link above explains how a VNA can be used to measure the length of a coax cable. A frequency accurate antenna analyzer can also be used to make these measurements.
The first part of our EME project is to put up a new tower to support our antennas. Our plans call for a 26′ tower built using three Rohn 55G tower sections. Four feet of the first section of…
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