M2 Antenna Systems 678-14 User manual

M2 Antenna Systems, Inc. 4402 N. Selland Ave. Fresno, CA 93722
Tel: [phone] Fax: [phone] Web: www.m2inc.com
©2022 M2 Antenna Systems Incorporated 08/22/22
Model .........................................678-14 (CH48-14)
Frequency Range.......................674-682 MHz
Usable Frequency Range ..........650-684 MHz
*Gain ..........................................16.8 dBi
Front to back ..............................25 dB Typical
Feed type ...................................Folded Dipole
Feed Impedance. .......................50 Ohms
Maximum VSWR........................1.2:1 Typical
Polarity .......................................Vertically / Horizontally
Input Connector..........................“N” Female
Power Handling ..........................500 Watts
Boom Length / Dia......................80” / 1” - 3/4”
Stacking Distance.......................E=42” / H=41”
Mounting.....................................1-1/4” to 2” Nom.
Wind area / Survival ...................0.5 Sq. Ft. / 100 MPH
Weight / Ship Wt.........................4 Lbs. / 6 Lbs.
M2 Antenna Systems, Inc.
Model No: 678-14 (TV CHANNEL 48-14)
FEATURES:
The 678-14 (CH48-14) is designed for deep fringe UHF TV reception where smaller Yagi’s and wide band compromise
antennas just don’t cut it. The antenna enables the “Polarity Flexibility” in any given application. Low cost yet
manufactured for dependability, the 678-14 (CH48-14), the folded dipole, provides a virtual flat match for over 10+ MHz.
The gain has been designed to roll-off quickly above range limits to prevent receiver overload from high power adjacent
channel interference. The heavy duty two piece boom and 3/16” elements, provide superior performance and longevity.
The 678-14 (CH48-14) is a DC grounded antenna designed to help protect receiver front ends from lightning and static.
Specialized single and multiple channel antennas are available for all TV and FM bands.
SPECIFICATIONS:
*Subtract 2.14 from dBi for dBd

678-14 (CH48-14) DIMENSION SHEET
REAR
CHAN-48 -14
(HI-PERFORMANCE 674-680 MHZ YAGI)
DIMENSION SHEET
FRONT
43.875
DECIMAL TO
FRACTION
CONVERSION
.062 = 1/16
.125 = 1/8
.188 = 3/16
.250 = 1/4
.313 = 5/16
.375 = 3/8
.437 = 7/16
.500 = 1/2
.562 = 9/16
.625 = 5/8
.688 = 11/16
.750 = 3/4
.813 = 13/16
.875 = 7/8
.937 = 15/16
66.500
73.688
80.000
51.250
59.313
22.874
29.625
16.062
36.937
5.875
3.250
10.437
0.000
ELEMENT
SPACING
7.188
7.125
7.000
7.000
7.000
7.000
CH48-14D
M. STAAL
10-12-05
FOLDED DIPOLE DRIVEN ELEMENT
7.188
7.125
7.062
7.750
7.437
7.313
ELEMENT
LENGTH
8.375

678-14 (CH48-14) ASSEMBLY MANUAL
GETTING STARTED
Tools handy for assembly process: Phillips head screwdriver, 11/32” nut driver or socket, 7/16” end wrench or socket.
Start by checking the parts needed to complete the assembly. You should have the following parts below:
1. CHAN48-14 Boom Assembly
2. Folded Dipole Assembly
3. Hardware bag and Uni-cradle Assembly
4. Element Assembly
1 2 3
Step 1:
Assembly the boom sections using
8-32 x 1-1/4 screws and locknuts.
Step 2:
Attach the folded dipole to the boom
using 8-32 x 1-1/4 screw and locknut.
(small hole)
Step 3:
Assembly the Uni-cradle and U-bolt to the boom with 1/4-20 nuts and
washers. Please note that you have the correct holes for your polari-
zation (vertical or horizontal) Attach boom assembly to tripod or
mast for ease of further assembly. NOTE: The U-bolt and nuts are
stainless steel and can seize. We suggest using WD40 or some
other lubricant when assembling.
4
Step 5:
Starting at the “Reflector” or rear of the
Boom (next to mast mount), install a
button insulator on each side of the
boom.
Step 4:
Unroll the element assembly and position the green line as your starting
point . Please note that the elements have already been center for you at
the factory using 3/16” retainer clip. The reflector will be the first element to
the right of the green line.

678-14 (CH48-14) PARTS LIST
Step 7:
Now move to the other side of the antenna. While
holding one side of the element, push a retainer clip
onto the other side of the element until it bottoms out
on the button insulator. Continue this procedure until
all elements are locked into place.
Step 6:
Starting at the rear of the antenna, hold the boom in
one hand and insert the first element into the boom.
Continue inserting first the button insulator and then
the next element in series until finished.
678-14 (CH48-14) PARTS LIST
10-12-05
DESCRIPTION ............................................................................QTY
BOOM, 1.0” X .058 X 36.00 SOE TO FIT 3/4”, ALUM .................. 1
BOOM, 3/4” X .049 X 37.75 ALUM................................................ 1
ELEMENTS, 3/16” X SEE DIM. SHEET........................................ 13
DRIVEN ELEMENT FOLDED DIPOLE ASSEMBLY..................... 1
BOOM TO MAST PLATE, 3 X 4 X 3/16” ....................................... 1
U-BOLT, 2”, .................................................................................. 2
U-BOLT, 1” , SS............................................................................. 2
ASSEMBLY MANUAL ................................................................... 1
IN HARDWARE BAGS:
NUT, 5/16-18, SS .......................................................................... 4
LOCKWASHER, 5/16” SPLIT RING SS ....................................... 4
NUT, 1/4-20, SS ............................................................................ 4
LOCKWASHER, 1/4” SPLIT RING, SS......................................... 4
SCREW, 8-32 X 1-1/4”, SS ........................................................... 3
LOCKNUT, 8-32, SS...................................................................... 2
SHAFT RETAINER (KEEPERS), 3/16” SS ................................... 26
BUTTON INSULATOR, POLY....................................................... 26
PUSH TUBE, 3/8” X 3” USED TO INSTALL KEEPERS .............. 1
M2ANTENNA SYSTEMS, INC.
4402 N. SELLAND AVE.
FRESNO, CA 93722
[phone] FAX: [phone]
www.m2inc.com Email: [email protected]
THIS COMPLETES THE ASSEMBLY OF THE 678-14 (CH48-14)