HF Mobile Antenna
Covers 80-6 Meters with 4 1/2 foot mobile or 10 foot fixed operation telescoping
whip. Continuously adjustable loading coil is 36 inches long by 2 inches in diameter and weighs 2.6 pounds.
$ 179.95 Each
MFJ 1668 MOBILE SCREWDRIVER ANTENNA
Introduction
The MFJ-1668 manually tuned screwdriver antenna was designed for continuous operation from
6-80 meters using a supplied whip 10 feet in length. The supplied 4 ½ foot whip can be used for
mobile or limited space operation.
The antenna is tuned by loosening a thumbscrew and moving the aluminum cover up or down the
loading coil. The loading coil is made of tin plated copper wire wound onto a PVC pipe core.
Copper Beryllium finger-stock is used to make the connection between the aluminum cover and
the loading coil.
WARNING: SERIOUS RF BURNS AND INJURY CAN OCCUR IF CONTACT IS
MADE WITH THE ANTENNA. PLACE THE ANTENNA IN AN OUT OF
REACH LOCATION.
Portable Operation And Mounting
The MFJ-1668 becomes a very efficient portable antenna when used in combination with a tripod
and a ground radial system. The antenna can be easily mounted onto a tripod such as the MFJ1918 or similar mount for portable operations. The MFJ-342 3/8 pipe mount easily attaches the
antenna to a tripod. The antenna must be properly connected to a ground radial system.
Portable Setup
1. Remove the antenna from the packaging.
2. Place a 3/8“ lock washer onto the 3/8 X 24 thread of the desired whip.
3. Carefully screw the desired whip into the 3/8 coupling nut located on top of the loading
coil.
4. Secure the whip in place with a 9/16 wrench.
5. Place a 3/8” lock washer onto the 3/8 X 24 mount on the base of the loading coil.
6. Screw the antenna into the desired mount 3/8 X 24 female mount such as the MFJ-342.
7. Secure the antenna in place using a 9/16” wrench.
8. Attach the counterpoise system to the ground shield of the feed-line. If using a MFJ-342
or similar mount attach the ground radials to one of the ¼” bolts located on the mount.
Check to make sure the ground system does not come into contact with the screwdriver
antenna.
Mobile Operation
The MFJ-1668 may be used as a mobile antenna by connecting the supplied 4.5 foot whip
onto the antenna. Also the 10-foot whip may be used when the vehicle is parked for
greater efficiency. NEVER ATTEMPT TO USE THE 10-FOOT WHIP WHILE A
VEHICLE IS IN MOTION. DAMAGE OR SERIOUS INJURY CAN AND WILL
OCCUR IF THE ANTENNA COMES INTO CONTACT WITH OVERHEAD
OBSTRUCTIONS OR POWER LINES.
MFJ-1668 Instruction Manual Screwdriver Antenna
Mobile Setup
1. Remove the antenna from the packaging.
2. Place a 3/8“ lock washer onto the 3/8 X 24 thread of the desired whip. ALWAYS USE
LOCK WASHERS FOR MOBILE INSTALLATIONS.
3. Carefully screw the desired whip into the 3/8 coupling nut located on top of the loading
coil.
4. Secure the whip in place with a 9/16 wrench.
5. Place a 3/8” lock washer onto the 3/8 X 24 mount on the base of the loading coil.
ALWAYS USE LOCK WASHERS FOR MOBILE INSTALLATIONS.
6. Screw the antenna into the desired mount.
7. Secure the antenna in place using a 9/16” wrench.
8. Attach a vehicle ground to the ground shield of the feed-line. The ground should be
attached directly to the vehicle frame or body. Check to make sure the ground system
does not come into contact with the screwdriver antenna.
Impedance Matching
For proper feed-point matching and operation, an impedance matching coil will need to be place
between the antenna and a ground. This will be more necessary for the lower HF bands such as
40 and 80 meters. Attach one end of an impedance matching coil to the wing nut on the lower
part of the antenna. Attach the opposite end to the ground radial system or vehicle ground
attached to the coax shield depending on your installation.
Tuning
The MFJ-1668 can be tuned very easily using a SWR analyzer such as the MFJ-259B. A radio
and an SWR METER may also be used. The resonant frequency of the antenna is adjusted by
loosening the thumbscrew located on the side of the antenna. The antenna should be setup in the
desired operating location using the instructions above. The ground system must also be installed
for proper operation. Follow the steps below to choose the desired operating frequency.
1. Check to see that the antenna is setup properly as instructed above.
2. Extend the whip to the full length.
3. Check the resonance point (a minimum SWR) of the antenna with the coil completely
shorted out. The coil is completely shorted when the coil is completely covered.
4. If a resonance point cannot be found check all of your connections including your ground
radial system.
5. To lower the operating frequency loosen the thumbscrew and slide the coil cover down
the coil. To increase the resonant frequency slide the coil cover up the antenna. Tighten
the thumbscrew and check the SWR as was done in step 3.
6. When the desired frequency is obtained tighten the thumb screw. Repeat the
above steps to find additional operating frequencies.
VHF
VHF Newsletter 83 – New VHF Handbook
The latest edition of the VHF Newsletter has been mailed to all on the VHF mailing list and can be found here. The new version of the VHF Handbook, 8.... Read more
BaoFeng UV-82HP (Camo) VHF/UHF
BaoFeng UV-82HP WHAT MAKES IT UNIQUE? * It has 3 Power Levels (1, 5, 7 watt) * VFO/ MR (Frequency Mode) can be locked via software * The Dual Push-to-... Read more
WRC-19: request to support 50MHz
As the run-up to WRC-19 gathers pace, the UK Six Metre Group has also written to Ofcom in support of a positive approach to Agenda Item 1.1 concerning... Read more
IARU Region 1 VHF Newsletter released
WRC 2015 When drafting this issue, the World Radio Conference 2015 had concluded his work. During 4 weeks more than 3000 participants attended this co... Read more
App - Mobile
Rfinder for Visually Impaired on Android
Rfinder Tom W3ZX, a visually impaired ham gives a great demo on Android using TalkBack for the visually impaired. See More: http://www.rfinder.net/blo... Read more
The World Wide Repeater Directory
RT Sytems and RFinder – The World Wide Repeater Directory bring integrated routing to radio progamming! Once again RFinder and RT Systems... Read more
What is Echolink? Ham Radio 2.0: Episode 56
Mark Goodrum, W5MHG, discusses Echolink for Ham Radio at the Duke City Hamfest Read more
EchoLink for iOS version 2.10.18 is now available
EchoLink for iOS version 2.10.18 is now available in the App Store. This is a 64-bit build that is fully compatible with iOS 10 and modern iOS devices... Read more
Review
How Your Radio’s Final Amp Class Affects Efficiency
An Oggie asks why his radio draws so much more power than the 100 watts it puts out. The answer lies in using linear final power amps in the Class A,... Read more
My Wife Bought More Radio Gear On Wish and Ali Express
My wife surprised me at the end of 2020 with a new random box of goodies from Wish and AliExpress. Today we unbox some of these ODD radios and radio a... Read more
FTdx10 vs IC-7300 Comparison
This week Jonathan compares the new Yaesu FTdx10 and the Icom IC-7300. What are your comments on either? Read more
ICOM IC-705 Review and Full Walk Through
Here’s the complete and detailed review of the ICOM IC-705. If you are already an owner of this unit, this video covers the essentials of the op... Read more
News
Capture the MAGIC of Six Meters — eBook
Have you ever wondered about the “Magic” of Six Meters? After all, you’ve probably pressed the six meter button on your rig and failed to find any mag... Read more
Eastern Iowans Rely On Ham Radio When Severe Weather Strikes
A derecho with winds of 80 to 100 MPH struck eastern Iowa last August, disrupting power and telecommunications for some 400,000 residents. But, as... Read more
David A. Duncan, K7DUN, Wins the January 2021 QST Cover Plaque Award
The winning article for the January 2021 QST Cover Plaque award is “CW-ELMER – An Advanced Morse Code Learning System,” by David A... Read more
ISS SSTV 145.800 FM Jan 28-29
Russian cosmonauts on the International Space Station (ISS) are planning to transmit Slow Scan TV images on 145.800 MHz FM using the SSTV mode PD-120.... Read more
