Type 3 Surge Protectors for SPGP

The Isobar surge protectors referenced in the book for mounting on the SPGP have a UL1449 Type 3 rating and carry a warning that they must be used 10 meters or more from the ac service panel.  The 10 meters (or more) of wiring adds inductance to the ac supply circuit that modifies the waveshape of the transient to make it easier for the surge protector's MOVs to withstand the surge.  In most stations, the SPGP is far enough from the ac service panel to meet this requirement.

If your SPGP is closer to the ac service panel than 10 meters, though, in addition to the Type 3 protector on the SPGP, you must add either:

a) a Type 2 surge protector at the circuit breaker for the protected circuit, or

b) a Type 1 "whole house" surge protector at the main breakers

The Square D #SDSA1175 surge protector is an example of a typical Type 2 protector and there are numerous Type 2 protectors on the market.  They typically install in one of the service panel "knock-out" and connect between the circuit breaker for the protected circuit (hot wire) and the neutral bus (white wire).

Do not simply add more cable to the branch circuit to make up a 10-meter length.  The extra cable can pick up the magnetic field from lightning and increase the magnitude of the resulting transient.

Size of Grounding Conductors

On page 3.11, the statement "The ground conductor must be at least as large as the current-carrying conductors..." is a good guideline but the actual wording of NEC Article 250.122 is that "the ground conductor can not be required to be larger than the current-carrying conductors." (Other ground conductor sizing rules are also given for situations unlikely to apply to amateur stations.)  This is a good example where the book must simplify the NEC rule in order to be understandable and useful to the individual ham.  If your station wiring is in any way unusual, unorthodox, or combined with other non-ham equipment, you should consult with a licensed electrician.

Old Power Strips with Surge Suppressors

The recommendation to avoid surge protectors was aimed at the inexpensive power strips that don't meet UL 1449 or that were manufactured before 2009 when the current version of that standard went into effect.  In addition to UL 1449, IEEE C62.62 establishes methods for testing and measuring the performance characteristics of Surge Protective Devices but doesn’t specify limits or ratings of any sort. IEEE 62.72 is a guide for manufacturers to aid in the selection of SPD’s for use on the AC mains, which is heavily biased towards MOV performance.  Those old strips are still powering a lot of stations - the author found two bad strips in his own collection, for example.  If you can't be sure the surge protection is up to current standards, remove them.

Building Your Own Power Distribution Box

Some readers asked about where to get multi-outlet cover plates.  The words to use in an internet search are "5-gang duplex receptacle wallplate" - you will discover a number of sources.  Wallplates are available with quite a variety of configurations and sizes.  Here is a 5-gang wallplate similar to that shown in the book.

Building the power distribution center requires attention to detail if you want the one you build to be safe.  Using in-wall back boxes is not OK in a wet environment, for example.  Be SURE the ground conductor is securely attached to the metalwork and can't come loose.  Plastic-housed strips meeting current standards are OK in this regard although they can't be grounded directly to an entry panel.

AC Surge Protector

The abbreviation PLDO is not defined in the book (see Figure 4.9) but it is discussed in the series of Ron Block NR2B articles in 2002 QST.  It stands for Protected Line Duplex Outlet (PLDO).  The PLDO contains surge suppressors to limit transient voltages on the output and protect the branch circuit it is connected to.  The PLDO should be mounted on a grounded panel or surface.  The Tripp Lite guide to surge protection might be helpful in selecting an appropriate model.  The original model only had 2 outlets (a duplex outlet) but available models have several duplex outlets.

DX Engineering sells panel-mounted ac line protectors for the amateur station
Tripp-Lite manufactures a wide range of ac surge protectors and line conditioners such as the 600 W 120 V panel-mountable LS604WM.
 

Portable GFCI - "GFCI In a Box"

Individual GFCI outlets are not intended for outdoor or portable use but there are portable GFCI units available (such as this one from Woodhead) that don't require assembly. The are designed to require line voltage be present before they can be "set" to operate, and disconnect automatically if either the hot or neutral connections are lost.

If you decide to build your own, the electrical aisle at hardware stores will have suitable weatherproof boxes and covered outlets such as these from Lowe's:

Electrical box  (you'll need a plug for the holes, too, or a sealed plastic box can be used)
Weatherproof cover
Sealed cord strain relief

You can also buy GFCI kits for outdoor use and installation - here's a photo of mine.  This box is sealed and has a waterproof cable entry, as well.

Installing a GFCI Receptacle - this downloadable PDF is a leaflet included by many manufacturers with GFCI receptacles purchased separately.

If you do build the GFCI-in-a-box or add a GFCI to a homemade power distribution box, the NEC specifically prohibits connecting multiple GFCIs in series. Standalone GFCI boxes should not be plugged into another GFI or GFI protected outlet, which should be present in any situations where water is within 3 feet of an outlet (RVs, park shelters, etc.)  Field Day generators may or may not be GFCI-protected - the popular Honda EB2000i generator outlets are GFCI-protected, for example - so check first.

WARC Band Chokes

Table A.5 - Ferrite Transmitting Choke Designs
For 18 and 24 MHz, us the second line of the 21 MHz entry

Table A.6 Coiled-Coax Transmitting Choke Designs
1.8 MHz - this technique is not recommended
18 MHz - for RG-213 and RG-8, use 9 feet of cable, coiled into 6-7 turns; for RG-58, use 7 feet of cable, coiled into 8 turns
24 MHz - for RG-213 and RG-8, use 7 feet of cable, coiled into 6-8 turns; for RG-58, use 5 feet of cable, coiled into 7 turns

If you would like to contribute an example of your own, please contact the author at n0ax@arrl.org or pubsfdbk@arrl.org.

Bonding

Jim Brown, K9YC, sent this photo of grounding jumpers (green wires) in the back of a nice portable station built by Glen Brown, W6GJB, for the California QSO Party.  The jumpers are all short and direct, keeping the equpment bonded together at RF.  Note the use of Powerpole connector to make disconnecting easy. The use of the standard green insulation and connectors for equipment ground wiring also makes the wires easy to identify as ground.

Single-Point Ground Panel (SPGP)

Contest operator K4RO decided to install a large SPGP to improve his station's ability to deal with lightning and to minimize RF voltage differences throughout the antenna switching and filtering system.  The panel is installed on an exterior garage wall under his station - which is effectively a second-floor station.  The ground conductor is attached at the upper right to ground rods installed outside the wall.

RF Ground Plane

Ken Chechura, KC9UMR, was rebuilding his station and got a great deal on some surplus wire rack shelving.  Not only does the wire mesh act as an RF ground plane, it provides for airflow that ventilates and cools the equipment, as well.

Dale Hammer, K9NN, is the equipment manager for the W9SU club.  In preparation for the 2021 Field Day, Dale built some very nice RF ground planes to use for each station. They are built with 20” wide roof flashing wrapped around 18”x48” fiberboard.  The 1” overlap on all sides is covered on the back by duct tape and also held in place with the copper pipe mounting screws.  Adding the power strip takes care of connecting the ac safety ground to the RF ground plane through the metal of the power strip enclosure.  The paint on the mounting tabs of the power strips is scraped to enable good contact with the flashing.   Dale reports that using these metal panels resulted in no problems with RFI at their 2021 Field Day operation.

Lightning Protection

This shows a set of DX Engineering lightning protectors mounted on an aluminum angle bracket at the author's station.  The bracket is then attached to a grounded aluminum panel.

No errata yet reported in the second edition.  All errata for the first edition were corrected in the second edition.