IC-703

Icom IC-703

The Icom IC-703 is a great choice for radio communications out in the wild such as when the SHTF. Not only is the size of the IC-703 attractive to preppers and survivalists alike it has a great many features that could be a great assets in survivalist and/or prepper situation. Some people will comment that the IC-703 radio is “just a QRP rig” and they might be right in a way. But a radio’s performance is based more on the antenna than on its power output. A good QRP rig such as the IC-703 works very well in mobile radio situations as well as with base station use. Running an IC-703 portable, such as a prepper or survivalist would do, is a very good application for this versatile little ham radio. Here are some of the features of the IC-703 radio by Icom:
  • Comes with a general coverage receiver
  • Many memories
  • RIT (receiver incremental tuning)
  • Preamp as well as an attenuator (although preamps are generally though to be worthless on the HF bands)
  • Dual VFO’s
  • 1 Hz display for tuning into odd frequencies
  • DSP, auto-notch, and noise reduction
  • SWR meter
There are TWO IC-703 models out there so be sure you look at a prospective purchase closely before you buy it. The last IC-703 was designated as an Icom IC-703 Plus designating it as the IC-703 with 6 meters in it. The original radios sold by Icom stated “HF/50MHz” on the front panel but that was a printing error. The early IC-703 radios did not have six meters in them so beware when buying an IC-703! As any honest amateur radio operator will tell you, a good antenna is the main part of a communications system. It doesn’t matter what band you’re operating on, what mode you are using, or even what radio you’re running. Preppers and survivalists alike need to learn to employ the best antenna they can come up with while still maintaining some sense of portability. Wire antennas, vertical antennas, and dipole antennas are good performers in the field or other portable operations. As has been mentioned elsewhere in this web site: “A dollar spent on an antenna is worth ten dollars spent on the radio.” For some reviews of the IC-703: ICOM IC-703 REVIEWS. IC-703 radio

Build Stealth Antennas

Build Stealth Antennas

Building stealth antennas to keep prying eyes from detecting your communications resources takes some skill and a lot of ingenuity. The skill part comes into play when it comes down to building antennas that will be sturdy and will perform optimally for the frequency/band desired. The ingenuity part of a stealth antenna comes about when it comes to hiding the antenna from nosy people with nothing better to do than to concern themselves with YOUR antenna. A lot of survivalists and others who want to hide their communications antennas think that mostly wire antennas are the type of antennas used the most and for the most part that’s fairly true. But that doesn’t mean that your HF/VHF/UHF beams and vertical antennas can’t be also hidden. In this picture to the right, you can see how easily a multi-element VHF beam was hidden in the average looking attic of this home. Admittedly it may not work as on receive or transmit as well as it would if it was mounted higher up on the outside Stealth Antenna 01of the home but it is thoroughly hidden away in the attic. Since this antenna is directional it has the characteristics of other beam antenna in that the transmit signal is higher in strength along with it having the ability to better receive signals that might otherwise be too weak to hear.

What Other Ways Can Be Used?

There are many but here are a a couple ideas to get your “idea factory” working on your own stealth antenna ideas.

This type of stealth antenna has been discussed elsewhere on this web site but it was decided that it should be included on this page. Can’t see the antenna yet? Just take a look at Old Glory wafting in the breeze and Stealth antenna 02you will see the antenna. Give up? It’s the flagpole! These flagpole vertical antennas are popping up all all over the place, especially where outside antennas are restricted or forbidden altogether. If you wish to erect any sort of flagpole antenna such as this one then you might want to be sure there aren’t restrictions on flagpoles in the area where you wish to erect it. Some homeowner associations have an even more restrictive policy towards communications by stating that no radio emissions are allowed. Of course this would not apply to shortwave listening but it is best to check first. The flagpole antennas are permanent as they require a concrete base under them and this might keep them from being used in some survivalist situations.

Stealth antenna 03
The owner of this home has built a loop antenna that literally circles his house and no one is the wiser. Take note of the coax exiting the attic vent and running over to the balun1 which is connected to the wire running around the eaves of the house. Wire loop antennas like this one are quite effect and stealthy as well. Along with this is the fact that loop antennas tend to be broadbanded and can readily used on more than one band.

Well, about the time you think you have seen it all there comes around something like the Stealth antenna 04antenna to the right of your screen. It is manufactured by Rohn Products and should hide any antennas systems contained within fairly well. Of course it will also tend to make people stop and point thereby drawing more attention to it than one might desire. Nevertheless, it shows what can be done to hide your antenna.

1 Balun: Derived from the terms “balanced” & “unbalanced”. It is an adapter that converts an unbalanced signal, eg 93 ohm coax to 100 ohm.

Wire Radio Antennas

Wire Radio Antennas

Wire Radio Antennas are sometimes maligned when it comes to their use for as base or portable antennas. While they may not beWire Radio Antennas as attractive as a multi-element beam up at 40 feet plus they are certainly no less effective. A wire antenna such as the dipole displayed to the right is a very effective antenna when cut for the frequency range you wish it to operate in. The majority of wire antennas you see will be for a single band meaning you will need an antenna for each band you will be operating on. There are some wire antennas that are deemed as multi-band when used with antenna tuner placed inline between the radio and the antenna. Wire antennas like the dipole pictured above are simple to make using the formula: 468 / frequency (in megahertz). All you need to do is divide the number 468 with the frequency you wish to operate. Now take this measurement and cut a single wire to that length, next cut this wire exactly in half and separate the pieces with an insulator as shown in the picture. All you need now is to connect some coax (radio cable) to the antenna by affixing the center conductor to one leg of the antenna and the shield of the coax to the other leg.

Mounting A Wire Antenna

The most popular way to mount a wire antenna is the inverted vee configuration where the center of the antenna is mounted asWire Radio Antennas high as possible and the ends come down to the ground forming an upside down V. As to be expected, the ends of the antennas must be insulated from the point where they are attached to the ground. One of the best ways is to use some sort of non-conductive material like plastic to attach to the end of the wire. Once this is attached to the ends of the antenna then you can tie the ends off to the ground with rope.

Other Wire Antennas

One of the simplest antennas as listed above is the inverted vee, but there is yet another equally effective antenna which is the simple dipole mounted in a horizontal configuration. Same method of design and building as the inverted vee but it is the mounting that differs from the inverted vee. Instead of placing the middle of the antenna up high you make both ends of the antenna as high as possible and as near the same height as possible. One drawback to this type of dipole is that the center insulator must carry the weight of the two antenna ends as well as the coax feedline. The feedline for these antennas can add a lot of weight to the antennas when you consider a length of feedline needed for an antenna 50 feet or more in the air. This issue alone is worth considering the inverted vee mounting configuration (unless you use a rope to support the full length of the dipole).

Delta Loop Antennas1

I am indebted to W4RNL for a large amount of information on Delta Loops. He has modeled many forms of this antenna and I would like to pass along some of his findings. All of the following were contained in a discussion forum on the QRP-L reflector, and were submitted by W4RNL (L.B.Cebik). For maximum vertically polarized radiation, the feedpoint should be 1/4 wavelength from the apex (whether pointed up or down).

The antenna should be relatively close to the ground. For a 40 meter model, 15 to 30 ft up to the bottom is max, and models k9ay delta loop antennasuggest that this scales for other bands. If higher at the bottom than about 0.2 wavelength, then a second high angle lobe develops, and stronger, closer in stations can override more distant stations, even if the lobe is not dominant in the pattern.

The Delta is at its limit on 20 meters of being a better DX antenna than a dipole, you will not get more gain from a Delta Loop over dipole, but it may exhibit a better signal to noise ratio – hence more comfortable listening.

THE DELTA LOOP IS A MONOBAND ANTENNA

Although the vertical-plane delta loop either pointed up or down and fed virtually anywhere will radiate well enough to provide contacts, it is a relatively poor performer in any configuration when stretched to other bands, compared to even the simplest substitute. Modeling of Delta Loops and similar antennas has proven to be a quite reliable indicator of performance, since nothing in the antenna type even approaches, let alone exceeds, the limits of the software for accurate modeling. So the following notes may be useful. These notes apply to vertical-plane equilateral delta triangles, although with some variation, they apply equally well to vertical-plane right angle deltas. Modeling was done on NEC 42.

First, the antenna. A vertical-plane equilateral delta for 40 meters will be about 48ft 5in wide and 42ft high. This places limits on the height above ground of the lowest point, since with a 35ft low-point height, the high point is 77ft up. For the examples below, a standardized 15ft bottom point is used, with a 57ft upper point.

  • When fed as a self contained vertical, maximum bottom heights of 20 to 25ft yield the highest gain (about 1.45dBi) with an elevation angle of maximum radiation of between 16 and 17 degrees. The first signs of a secondary higher angle lobe just make an appearance, but do not constitute a problem relative to the antenna’s use as a low-gain, low-angle DX antenna with superior signal to noise characteristics due to insensitivity to higher angle radiation.
  • As the antenna is raised by another 5 to 10ft, the secondary lobe increases, so that with a bottom height of 40ft, the antenna’s secondary high angle lobe at 60 degrees is down by only 4dB or so. As the antenna is lowered, gain decreases very slowly (imperceptibly), and the elevation angle of maximum radiation increases very slowly (about 1 degree for each 5 feet of lowering. A 15 ft lower wire or point height provides good performance within this class of antenna.
  • Moving the feedpoint to a mid-side location increases gain by increasing the amount of horizontally polarized radiation produced by the antenna. This increases the elevation angle of maximum radiation as well as spreading the main lobe vertically to permit considerable amounts of higher angle radiation. In effect, moving to far from the feedpoint prescribed for use of the vertical plane delta as a vertical antenna tends to defeat that purpose. However, the vertical-use feedpoint itself is not critical within say 5% or so of the recommended point.

How To Get My Wire Antenna Up High

Leave it to some people to use the materials at hand to make a difficult task easy. In this case you can use a converted fishing reel to launch the leader for the antenna line up into a tree and then pull the antenna up in place. More antenna about launching and mounting dipole antennas can be found here: mounting wire antennas.

1Delta Loop Antennas © JOHN REYNOLDS, G3PTO

2NEC 4 The Numerical Electromagnetics Code (NEC) is a popular antenna modeling software package for wire and surface antennas. It is credited to Gerald J. Burke and Andrew J. Poggio, and was originally written in FORTRAN in the 1970s. The code was made publicly available for general use and has subsequently been distributed for many computer platforms from mainframes to PCs.

Antennas

Antennas

Antennas play a vital part in any communication system and for more than the obvious reason that the radio simply won’t work without one. Radios, 2-way radio and receivers alike, can work with less than optimal antennas connected to them. But you will soon realize that the performance of the radio will also appear to be less than optimal. Ham radio operators are constantly working on and improving their antennas because they realize the importance of a fine tuned antenna. The ham operators even have a rule of thumb of sorts: “a dollar spent on the antenna is worth ten dollars spent on the radio”.

So where do antennas fit into a radio system used in a survivalist situation? The best answer to that question is yet another question which is ‘what do you want your radio to do?’. If you are looking for reception (and possibly transmission) of signals between countries or continents then you will be looking at a high performance HF1 antenna system. If you only need local or interstate communications then you can still use HF radio but with an antenna with less antenna gain.

Antenna gain. That’s likely a new word here for those interested in survivalist communications. Antenna gain is best explained by stating that an antenna can actually increase the power of a radio’s output signal. And by the same token you will enjoy better reception when an antenna has more gain to it. Without getting too technical you can read the specifications on a particular antenna and use the rough formula of 3db2 of antenna gain will give you twice the power output that you are feeding it from your transmitter. This means that theoretically you could feed 100 watts of power into an antenna with gain of 3db and it will appear to be 200 watts to those receiving your signal. So look at the gain of any antenna you contemplate using to see if it has a specification for gain. For each 3db of gain you get double the power, if your antenna has 9db of gain then your signal will sound like it is 300 watts.

Antenna types. This alone warrants a page alone. Antenna types for both almost all radios fall into these general categories:
  • Vertical (includes multi-element vertical beams)
  • Horizontal (includes multi-element horizontal beams)
  • Wire
  • Dish
Vertical antennas are just that, the antenna goes from the ground, or the mount, in an upward fashion.

Horizontal antennas run side-to-side and are usually found highBeam antenna up on top of towers or pushup masts with a rotator on it used to aim the antenna.

Wire antennas can be horizontal when hung between two or more supporting structures. Wire antennas are generally looked down upon as solid performers but we are looking more for portability, durability, and “stealthiness” when considering a wire antenna for use in a survivalist environment. That being the case you would be hard pressed to find another antenna that will fit all of these issues.

Most everyone knows what a dish antenna looks like, you only need to realize it is used for microwave radio frequencies and are unlikely to be used in survivalist environments.

Many have seen the various different types of antenna systems mentioned here without giving thought to one day using them as an survivalist. We have more information about antennas available from the links at the bottom and right side of this page. The information contained on the links at the bottom are the same pages as those on the right side of the page. They were placed in two different spots to make the information easier to access.

1HF when used to describe radio equipment refers to the High Frequency bands.

2db or DB stands for decibels and is a logarithmic unit of sound intensity.

antennas