Amateur Radio Antenna Remote Disconnect for Lightning Protection from alk on Vimeo.
Video by Art K4FWJ
A single lightning strike can destroy thousands of dollars worth of radio equipment. Experienced amateur radio operators know the only sure protection is complete disconnection. This can be a chore, especially when multiple antennas are involved. As well, it is all-to-easy to forget to do it. This system makes it possible to accomplish hands-off multiple antenna disconnects and re-connects either on-site or remotely. It also provides for antenna rotator connect/disconnect. The on-site mode can be wired to automatically connect antennas when the radio equipment is turned on and disconnect them when the radio is turned off. The remote mode requires a web IP switch which is controlled by a PC or smartphone. The result is excellent lightning protection at any time from any place.
Here’s more detail of the particular installation shown in this thread: The Polyphasers aren’t strictly necessary but in my case they were already in place. Plus, since they are well grounded, using them probably adds protection from a major strike that might arc over to the other side. Lastly, the SO-259 side needs to be very securely mounted to prevent any movement. The Polyphasers provide for that.
The Polyhasers were, by far, the most expensive item. Technical Distributors, Inc. sells them to Hams for $62.84 delivered.
The next most expensive item is the 6″ stroke 12V linear actuator which cost $46.95 on eBay, delivered.
The 12VDC power supply for the actuator cost $12.83 on eBay, delivered.
Drawer slides found at Lowe’s, Home Depot, etc., were excessively long. I found a pair 10″ slides on Amazon for $13.04, delivered.
It was very important to pay strict attention to the fixed position of the Polyphaser SO-259 centers. To that end a strong but thin plywood base plate was needed. Reason for that: relative to the SO-259 centers, the drawer slide thickness “lifts” the base plate and creates a substantial mismatch. To solve that problem a thin, 3/16″ X 12″ X 12″ piece of 4-ply aircraft grade plywood was used. Source: Sig Manufacturing website – $12.63 delivered.
The push-on PL-259 adapters were bought on eBay from W5SWL for $15.51 delivered for the four used.
The 1/8″ thick by 1-1/2″ wide aluminum angle can be bought in various lengths from a hardware store.
To make the thing able to be worked remotely an IP power switch is required. Remoterig makes one but I already had another version (IP-9258) so I used it. Also is used a small DPDT 12V relay. When energized by the station’s main 12V supply the relay sends correct 12V polarity to the actuator to make the coax and rotator cable connections. With a smartphone and IP Power’s free software, the IP switch is used to turn on the following: Alinco 12V 32A main power supply (which signals the small relay to send actuator power and connect coax), 12V standby power to an RF amplifier, 12V power to an RS-232 conversion PCB (from DF9GR) installed in a HAM-IV control box (the 110vac for the box is provided by the IP switch), 12V power to a flourescent lamp directly above the operating position. Even at home those things are turned on with my phone. Then a K3 is manually turned on with its’ front panel on/off button. When operating remotely the K3 gets turned on with a K3/0-mini which is connected to the RRC-1258 box. Also for remote operation is installed in a laptop running Win7 the following software: DXlab suite for logging, spots, etc, YO3DMU’s “PstRotatorAz” for the beam position, and SPE’s “Term_2K_232.exe” for amplifier control.
A Lantronix EDS2100 2-port server is needed to assist communication between PstRotatorAz and Term_2K_232.exe and their respective hardware (rotator/RF amp). EDS2100s are rather pricey. Found the one on eBay for $209.58, delivered.
Finally, before leaving home a webcam is placed in front of a P3 panadapter. A corresponding app on a smartphone relays band condition information surprisingly well.
Source: Art (K4FWJ)
P.S. Similar Project by SM3JGG – Link