ALPHA DELTA DX-B 160-80-40-30 METERS
*Please note that the support structure for the DX-B should be of metal construction and offer a low resistance ground pathway. The normal grounded tower found in amateur usage easily fills this simple requirement. If the tower does not offer a good ground return, then we suggest attaching a large diameter (No. 14 or larger) wire to the aluminum DX-B mounting bracket and running this wire to a good RF ground connection (ground rod) at the base of the support. This some method will allow the DX-B to be used in cases where the support structure may be of an insulated type, such as wooden utility poles, chimney mounts, trees, etc. Also, if your tower is of the "crank-up" variety, where there may be some doubt as to the integrity of the metal ground path, this same method of running a ground wire should be followed. If this method is needed, the DX-B aluminum-mounting bracket should be drilled for attachment of a stainless steel screw and lug type connector (with ground wire attached).
*Refer to FIGURE NO. 1: The DX-B aluminum mounting bracket will have to be drilled for a U-Bolt (user supplied) to fit your particular tower leg or installation method. It should be noted if your tower is of the "sectional" type (such as Rohn) then the bracket may be fitted to one of the sectional bolts by simply removing the nut and placing the bracket hole over the bolt and re-installing the nut! In this case, no other hole need be drilled, since the DX-B bracket has already been drilled with a single mounting hole at the factory!
*The DX-B was originally designed as a "free space" antenna (as almost all antennas are). As such, it is possible that the introduction of your DX-B into a tower system employing multiple guy wires or other attached wire antennas may cause detuning of the DX-B antenna. The mere presence of other wires or wire antennas can result in direct R.F. coupling which will upset the DX-B antenna system. The point of bracket attachment on the tower should be as far removed as possible from the attachment point for any guy wire system. The angle of slope for the elements of the DX-B should be such that they are not the same angle as made by any guy wires or other wire antennas. The DX-B wire elements may be so arranged as to bisect the angles mad by guy wires. Guy wires should be electrically broken by the inclusion of insulators. In some instances, it will be necessary to employ the use of an antenna tuner to allow some solid state transmitters to fully load.
*The mounting height for the DX-B is not critical. The DX-B is a super good low angle radiator (highly desired for DX work). We have many users with the DX-B mounted as low as 25 feet, and achieving excellent results on the air! Mounting height for the attachment of the bracket is best left to the decision of the end user and the support structure to be used for the DX-B.
*The DX-B has been designed for use on an unguyed metal tower with a beam on top. The beam provides a capacity hat effect and helps to tune the DX-B. The DX-B will provide excellent DX results on other support structures, such as poles, masts, trees, etc., but these installations will require the use of a wide range tuner.
INSTALLATION & TUNING INSTRUCTIONS
Unroll the DX-B sloper wire elements, removing any kinks that may have been induced during the packing operation. Run the 23-ft. "stub" wire through the pre-drilled acrylic stand-offs as shown in Fig. 1.
Install the DX-B aluminum-mounting bracket on your support structure, as described previously. Then slope the antenna as shown in Fig. 2 (optional "Down-Lead" not required if installed on metal tower).
Using a VOM, check to make certain that there is a good low resistance pathway between the DX-B bracket and the tower leg (or other ground return lead)! Also, be sure to route the wire from the end of the DX-B bracket so that it is separated from the tower leg as much as possible.
Any 50-ohm coaxial feedline may be employed for use with the DX-B Sloper Antenna. We suggest the use of RG-213 cable, as it is generally a very good buy and will handle the legal limit of RF power output. The DX-B bracket has been fitted with an Amphenol SO-239 connector so as to accept the standard PL-259 termination. Attach your feedline to the bracket coaxial connector. It is wise to cover this coaxial connection with some form of weather protectant, such as "COAX-SEAL", etc.
Please remember: the antenna end should be so placed that when installed it will not create a safety hazard since there will be RF voltage present at this end during normal use!
Turning Note: To raise the resonant frequency for any band, that wire element must be shortened. The shorter the wire element, the higher the resonant frequency. Conversely, the longer the wire element the lower the frequency.
The "ISO-RES" coil has been given two coats of special polyurethane with UV light blocking agent. All hardware is of 18-8 stainless steel. No further weatherproofing is needed. If you have some "COAX SEAL", a small amount may be applied to the copper element wire ends at the "ISO-RES". The construction of the "ISO-RES" is such that it should offer a long lifetime of service.
This completes the installation and tuning of your new ALPHA DELTA DX-B Sloper Antenna. GOOD DXING!
To avoid the possibility of tuning errors and false resonances you will need to de-couple the coax from the antenna at the feedpoint in the following manner. Near the feedpoint make 8 turns of coax at 8 inches in diameter. Tape these turns with electrical tape. Then tape the entire set of turns to the tower leg or at a convenient place so it doesnt pull at the PL259 connector.