Letter Re: Build Your Own HF Transceiver Antenna

The following is my contribution to SurvivalBlog about antennas for High Frequency (HF) Transceivers. One antenna that has served me well over the years and easy to build is the G5RV antenna. Louis Varney, a British ham, came up with idea for the G5RV which also his call sign.

The G5RV is a dipole antenna with 51 foot legs and the center feed point being 28’6″ of 300 ohm twin lead transmission grade twin lead connected to RG58 coaxial cable (“coax”). There are other construction methods, but for simplicity, we use a 1″ outside diameter PVC Tee to create a center feed point. To seal this all up I used caps and cemented them to the two openings closed. Before you seal them up you drill a hole in end caps and slip them over the 51 foot length of wire and put a knot in the end of the wire that will be inside the tee. Pull both lengths of  wire through the tee and using a 10 to 12 inch section of PVC pipe that you cement in the opening that will point down the wire through the tubing and solder to the 300ohm twin lead. Before soldering the twin lead split it down middle about six inches. The reason for this is to allow the twin lead a little room feed the wire you will solder the twin lead to. This is where you have to eye this very carefully because once you seal this up in the tee then you are “up the creek” if you did not do it right. At the bottom of the PVC tubing we drill a couple of small diameter holes to slip a couple of tie wraps through to form a strain relief  on 300 ohm twin lead. Put enough caulking inside the end of the PVC to seal it up. On the tee I usually tie 550 cord or equivalent  small diameter rope so you throw this up in a tree and pull it up in a tree or a mast.  The length of RG58 we use is about 50 ft. at the most you can use more. But due to power loss we would keep it to that magic 50 foot mark. This just a guess but through 35 years experience as a two radio tech and U.S. Merchant Marine radio officer on Navy ships. Use your imagination connecting the twin lead to the coax.

When you solder this up make sure you do not short out the coax, We highly recommend using a 30-40 watt soldering iron to solder all connections. concerning the end of the dipole legs. We have used a one inch diameter PVC pipe/tubing cut to the length of four inches. Drilling holes in both ends put the wire from the dipole leg through it and using about a foot. wrapping a the wire around itself until you wrap it all the way. Then wrap electrical tape around to protect the end of the wire and keep moisture out.The other end put  a length of 550 cord though it and use it to tie off the dipole legs  I use Radio Shack  PL-259 crimp-on connectors for the connector to connect to the coax to the antenna tuner.  

Now concerning antenna tuners for the HF ranges. This probably is a mystery to you who are reading this posting. But to use a dipole or any other antenna with a HF transceiver you probably need an antenna tuner. HF transceivers cover from 1.8 to 30 MHz . This is not like your CB radio, as it uses a small section of the HF frequencies. 26.5 to 27.5 Mhz and this only a guess. We are covering almost 30 MHz with a real HF transceiver.

You match the different impedance  to the radio. The radios are set up to work with 50 ohm inputs. Using the antenna tuner you match the radio to the antenna keeping the 50 ohm match to the radio. Now what brands are out there that affordable and reliable. Over the years we have used a MFJ 949D/E etc antenna tuner it match  many a ham transceiver. MFJ Enterprises makes a great line of HF tuners. Also, I’s would like to write about automatic antenna tuners. One brand we have used and very happy with is LDG Electronics. LDG makes a variety of  tuners. The one which I chose for simplicity and the price was the Z-100. This operates on the same 12 VDC power supply that many ham HF radios already have available.  LDG and other manufacturers make connecting cable to use with different radios. We used the Z-100 with a Yaesu FT857D  which is small HF solid state transceiver and also has 6 meters, 70cm, and 2 meters. We used this combination while on a month-long school in Florida, six years ago. I used a commercial antenna that adjustable in length up to a hundred feet.

In closing, this is one of many wire antennas that can be used portable as well fixed location. Also another radio that is small (and also 100 watt) is the Icom 706 MkIIG, a great little radio with a good receiver. A lot of the information you will need is on the Internet and also in amateur radio books.

Just one final warning: Don’t just get a HF rig and get on the air without a license. A lot of ham radio operators will direction find (DF) you, and turn over to the FCC. In an emergency you do not need a license. – Ben N.