This document describes the Alpha Delta Multi-Band Wire Dipole Antennas and their associated hardware kit. It provides detailed instructions for assembly, operation, and maintenance, along with important technical specifications and usage considerations.
Function Description
The Alpha Delta Multi-Band Wire Dipole Antennas are designed for amateur radio use, offering multi-band operation for various HF frequencies. These antennas are precision-made in the U.S.A. in an ISO-9001 certified facility, emphasizing high quality and efficiency. They utilize ISO-RES™ inductor coils, which are described as highly efficient for multi-band operation, approaching mono-band performance, unlike traditional lossy traps. The antennas are designed to be used without a balun, as tests show that HF antennas installed less than 1/2 wavelength high (e.g., less than 60 ft. high on 40 meters) have earth capacity coupling that tends to "even out" the pattern. A "choke balun" can be created by winding about 8 turns of coax at an 8" diameter near the feed point if RF on the coax is a problem.
The DELTA-C Antenna Hardware Kit provides the necessary components for constructing and installing these wire dipoles. It includes a DELTA-C Center Insulator, antenna connecting hardware, a Model SEP Arc-Plug™ static electricity protector, and two Model DELTA-CIN End Insulators. The DELTA-C components are molded from DELTALLOY™, a high-impact, UV and RF resistant material, ensuring durability. All exposed hardware is stainless steel.
Important Technical Specifications
Power Ratings (at 2:1 SWR or less at feed point, not tuner):
- Model DX-CC: 80 thru 10 meters, 1000 watts CW/PEP, ICAS duty cycle.
- Model DX-DD: Same as DX-CC for 80 and 40 meters.
- Model DX-EE: 40 thru 10 meters, 1000 watts CW/PEP, ICAS duty cycle.
- Model DX-LB: 160, 80 meters, 600 watts CW/PEP; 40 meters, 1000 watts CW/PEP, ICAS duty cycle.
- Model DX-LB PLUS: Same as DX-LB for 160 and 80 meters, and same as DX-CC on 40 thru 10 meters.
- Continuous Key Down Modes (e.g., RTTY): All models are limited to 250 watts RF output to prevent overheating.
- Attic Installations: Limit power to 100 watts max, any mode, to minimize coupling to attic wiring, HVAC ducting, outside aluminum gutters, and RFI to home electronics and burglar alarm systems.
SWR Bandwidth:
- Model DX-CC (80 meters): Approximately 65 kHz (narrow SWR bandwidth due to shortened "Hi-Q" design).
- Model DX-DD (40 meters): Broadband if installed in the clear.
- Model DX-EE (40 meters): Approximately 70 kHz (narrow SWR bandwidth due to shortened efficient Hi-Q design).
- Model DX-LB (160 meters): Approximately 20 kHz (greatly shortened design).
- Model DX-LB (80 meters): Approximately 40 kHz (due to extra coil).
Antenna Lengths (Overall Total for both sides of dipole):
- Model DX-CC: 82 ft.
- Model DX-DD: 82 ft.
- Model DX-EE: 40 ft. (or 42 ft. overall, depending on reference)
- Model DX-LB: 100 ft.
- Half-Wave Overall Lengths (Approximations from DELTA-C Hardware Kit):
- 160 Meters: 260 ft.
- 80 Meters: 126 ft.
- 40 Meters: 66 ft.
- 30 Meters: 46 ft.
- 20 Meters: 33 ft.
- 17 Meters: 26 ft.
- 15 Meters: 22 ft.
- 12 Meters: 19 ft.
- 10 Meters: 16.5 ft.
Model SEP Arc-Plug™ Static Electricity Protector:
- Gas tube component designed to "bleed off" slow rising static electricity.
- Rated for 1000 watts PEP/CW assuming feed point SWR is 2:1 or less.
- Designed to fail "shorted" if a strong surge "hit" exceeds its rating, indicating need for replacement.
- Note: Models DX-LB and LB Plus do not use the SEP protector due to high VSWR voltage swings when tuning on 160 and 80 meters, which could cause "false triggering."
Usage Features
General Operation:
- SWR Check: Always check SWR at the antenna feed point (not the tuner). If SWR is higher than 2:1, de-rate power to 1/2 the shown ratings to prevent overheating.
- Attic Installations: Require a wide range (10:1) antenna tuner to minimize SWR and broaden bandwidth. Keep antenna wires at least 3 ft. from metal items and never touching them. Offset wires at least 2 ft. from wood roof/attic trusses or roof material.
- Tuning: For narrow bandwidth antennas (e.g., 80m on DX-CC, 40m on DX-EE, 160m/80m on DX-LB), adjust length by pulling wires through end insulators and twisting back to move frequency. A wide range tuner can broaden coverage.
- WARC Bands (30, 17, 12 meters): These models do not have natural resonances on WARC bands but can be used with a wide range (10:1 tuning range) antenna tuner. Due to high SWRs on these ranges, remove the SEP module from the DELTA-C center insulator and de-rate power.
- Balun: Alpha Delta antennas are designed to be used without a balun. If RF on the coax is an issue, a choke balun can be made by winding 8 turns of coax (8" diameter) near the feed point.
Model Specific Assembly and Tuning:
- DX-CC: 82 ft. overall. "Top wire" (40, 15, 80m), "Middle wire" (20m, approx 16 ft. each side), "Bottom wire" (10m, approx 8 ft. each side). Uses 3 long and 3 short stand-offs. For 80m, shorten ends by 6-8 inches for 75m SSB.
- DX-DD: 82 ft. overall. Uses only the "top wire" for 80 and 40 meters. No stand-offs.
- DX-EE: 40 ft. overall. "Top wire" (40, 20m), "Middle wire" (15m, approx 11 ft. each side), "Bottom wire" (10m, approx 8 ft. each side). Uses 3 long and 2 short stand-offs. For 40m, shorten far ends by 3 inches for 40m SSB.
- DX-LB: 100 ft. overall. Similar to DX-DD but with extra coil and extender wire for 160m. For 160m, install as high as possible (>40 ft.). Shorten ends by 4-6 inches for 160m SSB. A tuner should be used for 80m and 40m.
- DX-LB Plus: Same as DX-LB but adds parallel wires for 20-10 meters (assembly similar to DX-CC).
DELTA-C Hardware Kit Assembly:
- Feed antenna wire through strain relief holes, wrap 3-5 turns, then route to solder lug.
- Form a small loop from the wrap to the lug for tension relief.
- Ensure hardware (washers, nuts) is reinstalled in the correct sequence and not overtightened.
- SEP Protector: Requires grounding the coax shield at the building entrance. If it fails, VSWR will increase significantly, or the receiver will be "dead." To remove, detach antenna hardware and pull out the SEP from the cavity on the back of the DELTA-C.
Safety:
- NEVER install an antenna near power or drop lines. Contact can cause death, injury, or fire.
- For maximum lightning/EMP protection, use an Alpha Delta Transi-Trap Surge Protector where the feedline enters the building.
Maintenance Features
Coil Maintenance:
- Remove Packing Material: Before installation, remove all bubble wrap or packing material from the ISO-RES™ coils. This material is for shipping protection only and affects tuning/efficiency.
- No Additional Coating: The coils have a UV protective dip applied at the factory and require no further coating or treatment. Other coatings may affect tuning and efficiency.
- Environmental Effects: It is NORMAL for the frequency to shift with rain, snow, or high humidity due to the "open coil" design. Simply re-adjust your tuner until dry again.
- Check Coax: Inspect coax cables and "jumpers" for shorts at either end.
- SWR Run: Perform a slow SWR "run" across each band (every 20 kHz from band edge to edge, then smaller increments) to find the exact SWR minimum. This data helps diagnose issues.
- Installation Site: Poor tuning and performance are often traced to installation site problems (surrounding objects, height above ground) or improper assembly. HF antennas are very sensitive to coupling with surrounding objects like gutters, roofs, guy wires, or "earth coupling" when low to the ground.
SEP Protector Replacement:
- If the Model SEP protector takes a strong surge "hit" beyond its rating, it will fail "shorted," indicated by a large increase in VSWR or a "dead" receiver. It must be removed and replaced. Your equipment will remain protected until removal or replacement.
General Durability:
- Alpha Delta antennas use stainless steel hardware and insulated high tensile strength solid copper 12 ga. wire to withstand severe environments.
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