The Answers You Need
HOW CAN I TUNE THE ANTENNA?
The element length is adjustable by about 20mm per leg, for a total of 40mm in over all length. Shortening up the overall length puts you on the higher side of the tune. Lengthening puts you down farther. You simply remove the cover and loosen the adjustment screws to push or pull the elements along the adjustment contact clamps. A SWR or VNA meter is highly recommended for this operation.
WHAT KIND OF SWR CAN EXPECT?
Each one of our antennas is hand tuned to the approximate center of each band supported. Typically on 2 meters the SWR is < 1.2 but can very to as high as 1.3 it is higher for the 70cm band however, anything greater than 1.3 on either band is not deemed acceptable to ship.
WHAT IS THE WATT RATING FOR THE 2M/70CM ANTENNA?
The antenna is currently rated for 65watts. This is the level we have tested it to. If you plan to use it at higher levels you may do so at your own risk.
FOR THE 2M/70CM DIPOLE, IS THERE A BALUN IN THE ANTENNA, OR DOES IT JUST HAVE THE CENTER CONDUCTOR ATTACHED TO ONE SIDE AND THE JACKET CONNECTED TO THE OTHER SIDE?
A balun is not required. The antenna internal match provides for ~50ohms match.
HOW DO I ADJUST/TUNE THE ANTENNA?
Here are the steps. (NOTE: Remember, when tuning this dual band antenna, adjusting the tune for one set of band frequencies will affect the other band. Thus shortening the 2m element will affect the 70cm element and visa versa. Use extreme caution if you decide to trim the elements. As you may render the unit unusable on a particular frequency or band.)
1. Open up the unit by removing the 4 screws on top and exposing the internals of the antenna.
2. Connect your network analyzer to the SO239
3. Loosen the element screws that hold the elements in tune.
4. Slide the elements in or out to adjust the tuning. (Note: you may have to slide the element separators to accommodate this)
5. Retighten the element screws.
6. Trimming the 2m length, depending on the desired tune you may wish to trim the elements to do so, >> If you have a V1 antenna you can also trim the end of the antenna easily by removing the white ball from the end. >>If you have a v2-v4 antenna you will need to de-solder the coronal balls from the end of the antenna to trim it.
7. Trimming the 70cm length, slide the outermost element separator off of the 70cm element and trim as necessary.
8. Retest with your analyzer.
9. Repeat as necessary until you reach the desired frequency.
10. Reposition the element separators back to their general relative positions.
11. If using a V2-V4 antenna reattach the coronal discharge balls
12. If using a V1 antenna replace the protective safety ball on the ends of the antenna.
13. Reseal the unit using a high quality silicone sealant.
14. Replace the top cover screws.
(NOTE: If Trimming is performed on the elements the warranty on the elements is void, Breakage due to customer maintenance or abuse is not covered by warranty. In our lab, we never trim more than 3mm or 1/8th inch at a time. New elements may be acquired for a nominal charge of $7.00 USD +Shipping.)