ALPHA DELTA DX-CC 82 FT. LONG "NO TRAP"

 

INSTALLATION NOTES

**Due to the fact that the ALPHA DELTA DX-CC antenna approximates a half wave dipole (although greatly reduced in length), the method of mounting or installing it does not present some of the problems associated with other types of antennas. Towers, trees, wooden utility masts, etc. may all be employed as the support structure for the ALPHA DELTA DX-CC!

*Refer to Figure No. 1: The DX-CC may be installed as in inverted seem flat top dipole, sloping dipole, etc. The inverted vee configuration seems to be the easiest for most amateurs to utilize. It has several benefits, such as requiring but a single central support structure for the DX-CC center insulator. Remember, though the ALPHA DELTA DX-CC was designed for compromise installations where there are space limitations. A little thought will allow the DX-CC to be installed in spaces normally thought to be too small for an antenna for these frequency bands!

*Tower mounting height for the DX-CC will require some form of "stand-off" for support of the DX-CC center insulator. A spacing of 18" or more away from the tower will prove adequate.

*Mounting height for the DX-CC is not overly critical. However, as with most half-wave antennas, the higher and in the clear, the better. Let the space you have available dictate the mounting height and scheme of installation. The antenna has been tested at a height of 35 ft. Lower heights may cause higher VSWR.

*The introduction of your DX-CC into a tower system employing multiple guy wires or other wire antennas may cause detuning of the DX-CC antenna. This may be evidenced by a shift in the resonant frequency or increase in the minimum VSWR of the antenna. Try to keep the DX-CC as "in the clear" as possible. Installing the DX-CC so that it is in a different plane than guy wires will help, as will "breaking" the guy wires with strain insulators. For some installations, it may be necessary to employ the use of an antenna tuner to overcome this detuning situation.

*The DX-CC utilizes the exclusive ALPHA DELTA ISO-RES coil principle for shortening and multibanding an antenna. The ISO-RES is not a trap, due to the fact that there isn’t a trap capacitor being used. Thus, the DX-CC is a much lower "Q" antenna than one that would be constructed using true traps! This allows the DX-CC to be broader in bandwidth than is possible with a trap-type antenna of equal size. The lower "Q" also allows the user to employ a moderate range antenna tuner (matchbox) for achieving resonance and min. SWR anywhere within the covered frequency bands.

NOTE: Some automatic antenna tuners in transceivers do not have the impedance range to tune the Model DX-CC on bands other than the covered ranges. An external wide range tuner may be required.

 

INSTALLATION INSTRUCTIONS

 

Unroll the DX-CC wire elements, removing any kinks that may have been induced during the packing operation. At each side of the center insulator you will find 3 wires:

A 80/40 15 meter wire with an ISO-RES coil and 6 stand-off insulators installed. (Approximately 41 ft. long)

B. 20 meter wire. (Approximately 16ft. long)

C. 10 meter wire. (Approximately 8 ft. long)

With the antenna wires laid out on the ground in a fully extended condition, run the 20 and 10-meter wires through the stand-offs as shown in FIG. 2 with the 20 meter wire running through the center holes of the 3 long stand-offs and through the bottom holes of the 3 short stand-offs. The end of the 20-meter wire should be twisted back on itself around the last stand-off for proper support, after being made taut. The 10-meter wire is run through the bottom holes on the 3 long stand-offs as shown. It is then twisted back on itself around the last long stand-off, after being made taut. All of the stand-offs should be spaced equally along the wires for best support. When all of the wires and stand-offs have been positioned properly, tightly wrap wire-ties around the top and bottom of each stand-off and antenna wire to prevent movement. See FIG. 2 for method. For the wire-ties, cut approx. 6" lengths from the 12-ft. coil of wire provided. Choose the arrangement for mounting your new DX-CC, (inverted vee, flat top dipole, etc.). If the inverted form is chosen cut a short length of the supplied rope to each end insulator of the DX-CC. Tie the remaining two pieces of rope to each end insulator of the DX-CC. Any 50-ohm coaxial cable may be employed for use with the DX-CC. We suggest the use of RG-213 as it is generally a good "buy" and will last many years. Installations where only low power operation is being used can get by with RG-58A/U or RG-8X type coax. If the inverted vee configuration is to be used, try to arrange the ends of your DX-CC so that when viewed from the side the angle at the apex of the antenna is 90 degrees between the two element wires – see Figure No. 1.

The two ISO-RES coils have been coated with very special polyurethane with UV light block polymer, and require no further coating or protection. A small amount of coax seal placed around the bare copper ends of the element wires (at the screws) on the coils would be helpful. When placing any coaxial sealant over the SO-239 coax connector on the bottom of the DX-CC center insulator, be certain not to cover the four drains holes provided to allow moisture release! When tying off the two ends of your DX-CC, allow a small amount of slack (or sag) in the system. Don’t cinch the elements down snug!

 

TUNING AND OPERATING INSTRUCTIONS

Your ALPHA DELTA DX-CC has been set at the factory for resonance within the 80, 40, 20, 15 and 10 meter bands. With proper installation, you should easily find the resonance points within these covered bands. The design of the DX-CC is such that the normal VSWR on 10 meters is approx. 2:1, with the VSWR on the other bands approaching 1.5:1 at resonance. The VSWR curve on 20, 15, and 10 meters is usually broad enough, depending upon the installation site, that fine tuning and trimming on these bands is not normally worth the effort. Additional radiation efficiency is typically not realized. If VSWR is higher than specified for you rig, just use an antenna tuner and enjoy the antenna as is! (No separate adjustment is available for 15 meters since it is a third harmonic of the 40-meter section).

*IF THE USE OF AN ANTENNA TUNER IS PLANNED --- NO TUNING OR MODIFICATION IS NECESSARY. PUT IT UP AS IS AND ENJOY IT!

*Should the installation be such that it is detuning the DX-CC, we recommend the use of an antenna tuner to cancel the reactances and achieve normal swr and resonance.

*We recommend the use of a good, wide range antenna tuner (matchbox) for use with the DX-CC on the 80M band. Many manufacturers offer such tuners for sale, or one may refer to any of the "handbooks" for a construct-it-yourself project!

*When installed in the inverted vee configuration, minimum SWR may be regulated (to a degree) by varying the included angle (apex angle) and the mounting height. Since each installation offers its own set of variables, this work must be done on a somewhat "trial and error" basis.

*An open wire "ladder" type feedline (a balanced feedline) may be used with the ALPHA DELTA DX-CC. Please note on the main diagram the two arrows labeled "a". The two conductors of your balanced feedline would be needed for such an optional installation and would allow low loss Multi-brand operation. 8-32 stainless steel washers and nuts required.

*For a convenient way to lower the operating frequency on the 40M band, please refer to Figure No. 2 where the installation of the stub tuning wires are shown. Please cut a 6-ft. length of wire into two equal lengths. Install one of these wires under the innermost nut on the ISO-RES coil. Repeat this for the ISO-RES on the other side of the DX-CC. Trimming these two stub-tune wires will allow the user to adjust the 40M resonant frequency to the point desired. To raise the operating frequency on 40M, the main 40M wires must be shortened as necessary to reach resonance.

Remember to strip the insulation from the connection end of the stub tuning wire.

* To lower the operating frequency on the 80M band, a small length of wire may be soldered to each side at the ends of the DX-CC. These ends may then be trimmed to achieve the desired operating frequency. To raise the operating frequency on 80M the 80M wires must be shortened as necessary to reach resonance.

*The DX-CC may be operated on the entire amateur HF bands with the incorporation of a good antenna tuner into the system! Using the antenna tuner in the system will allow full operation WITHOUT ANY MODIFICATION OR TUNING OF THE DX-EE!

*If a tuner is to be used in a multi-band arrangement (all HF bands), a recommended alternative arrangement would be to short the shield and center conductor of the coax at the transmitter end, then connect as "long wire" to the random wire output of the antenna tuner. This system has worked very well during our many tests of the DX-CC. For these installations the antenna tuner must be well grounded.

*Periodic clearing of the drain holes near the SO-239 connector will reduce build up of residue such as spider webs, etc.