HQ Series
SPECIFICATIONS STANDARD *SPECIAL
ELECTRICAL
Center Frequency (Fc) 100 to 1000 Mhz 80 to 1400 MHz
3dB Relative Bandwidth (% of FC) 4 to 40 4 to 50
Number of Sections Available 3 to 8 2 to 10
Nominal Impedance 50 Ohms 50 to 75 Ohms
Maximum Insertion Loss See Curve See Curve
Maximum VSWR 1.5/1 1.3/1
Attenuation in the Stopband See Graph See Graph
Maximum Input Power (Average)(Watts to
10,000 ft.) 500 x 3dB BW (MHz)
(Loss Factor)(Fc MHz) See Standard
Maximum Input Power (Peak)(Watts to
10,000 ft.) 300 x 3dB BW (MHz)
Fc (MHz) 2,000
ENVIRONMENTAL
Shock 15 G's 25 G's
Vibration 5 G's 10 G's
Humidity 90% relative 100% relative
Lark Engineering HQ SERIES
http://www.larkeng.com/BDPASS/HQ.htm (1 of 4) [1/17/2002 2:30:33 PM]
Altitude Unlimited Unlimited
Temperature Range (Operating) -25 to + 50 degrees
celsius -54 to + 85 degrees
celsius
Temperature Range (Non-Operating) -54 to + 70 degrees
celsius -54 to +100 degrees
celsius
MECHANICAL
Approximate Weight 0.75 oz. per inch 0.75 oz. per inch
Mounting Provisions See diagram See diagram
INSERTION LOSS:
The Maximum Insertion Loss at
center frequency is equal to :
LF x (N + 0.5) / % 3 dB BW + 0.2
Where:
LF= Loss Factor, N= Number of
Sections
% 3dB BW:
3dB BW (MHz) x 100
divided by
Center Frequency (MHz)
Example:
A 3 section HQ with a center
frequency of 400 MHz and a 3dB
BW of 40 MHz would have,
1.5 x 3.5 / 10 = 5.25 / 10 = 0.525
0.525 + 0.2 = 0.8 dB
Lark Engineering HQ SERIES
http://www.larkeng.com/BDPASS/HQ.htm (2 of 4) [1/17/2002 2:30:33 PM]
Connectors Available on HQ Series:
Lark
Code Type C DIM.
Inches & MM Lark
Code Type C DIM.
Inches & MM
A SMA JACK .800 & 20.3 G N JACK 1.625 & 41.3
B SMA PLUG .855 & 22.5 H N PLUG 1.585 & 40.3
C TNC JACK 1.350 & 34.3 L SOLDER MPIN
AXIAL .625 & 15.9
D TNC PLUG 1.280 & 32.5 *M SOLDER PIN
RADIAL .625 & 15.9
E BNC JACK 1.350 & 34.3 S SPECIAL
F BNC PLUG 1.280 & 32.5
*Not recommended for use with this series.
Lark Engineering HQ SERIES
http://www.larkeng.com/BDPASS/HQ.htm (3 of 4) [1/17/2002 2:30:33 PM]
LENGTH:
The approximate length of a Lark HQ series filter can
be determined by the formula:
( 0.5 N + 2 / %BW ) x LC = L
Where N is the number of sections used, % BW is:
3dB BW (MHz) x 100
divided by
CENTER FREQUENCY (MHz)
LC is the length constant at the specified center
frequency, L is the dimension between the
connectors; C1 and C2 are the connector lengths as
shown above. All of the length information given
here is approximate. Exact length specifications must
be quoted by the factory. If a special length is needed,
please submit all of your requirements - both
electrical and mechanical. This will enable Lark
Engineering to quote the optimum design for your
application.
Example:
A 3 section HQ with a center frequency of 400 MHz
a 3dB BW of 40 MHz and SMA jack input and output
connectors would be:
(1.5 + 0.2) x 1.38 = 2.35 + C1 + C2
In most cases, the L dimension is rounded to the
nearest 1/4 inch which in this instance would be 2.25
inches and the O.A.L. is:
2.25 + .800 + .800 = 3.85 inches.
To convert inches to millimeters multiply x 25.40.
Lark Engineering HQ SERIES
http://www.larkeng.com/BDPASS/HQ.htm (4 of 4) [1/17/2002 2:30:33 PM]
STOPBAND ATTENUATION
The graph on the following pages defines the normal specification limits on attenuation Lark bandpass
filter series HP, HQ, SF, and SM. The minimum level of attenuation in dB is shown as a "number of 3dB
bandwidths from center frequency".
Since the frequency characteristics vary for differing bandwidths, it is necessary to establish
specifications for each bandwidth of filter. The different graphs represent various 3dB percentage
bandwidths. Intermediate values should be interpolated. The 3dB percentage bandwidth is defined as
follows:
STOPATT5.HTM
http://www.larkeng.com/BDPASS/stopatt.htm (1 of 6) [1/17/2002 2:30:50 PM]
As the 3dB bandwidth is exactly 10% of the center frequency, the answer can be read directly from the
10% graph. Using the 5 section curve at the point -1.5 (255 MHz) we find the minimum level of
attenuation is 36dB. At +1.6 (348 MHz) the minimum level of attenuation is 48dB.
For special requirements, please contact our Application Engineering Department.
STOPBAND ATTENUATION
STOPBAND ATTENUATION
STOPATT5.HTM
http://www.larkeng.com/BDPASS/stopatt.htm (2 of 6) [1/17/2002 2:30:50 PM]
STOPBAND ATTENUATION
STOPATT5.HTM
http://www.larkeng.com/BDPASS/stopatt.htm (3 of 6) [1/17/2002 2:30:50 PM]
STOPBAND ATTENUATION
STOPATT5.HTM
http://www.larkeng.com/BDPASS/stopatt.htm (4 of 6) [1/17/2002 2:30:50 PM]
STOPBAND ATTENUATION
STOPATT5.HTM
http://www.larkeng.com/BDPASS/stopatt.htm (5 of 6) [1/17/2002 2:30:50 PM]
STOPATT5.HTM
http://www.larkeng.com/BDPASS/stopatt.htm (6 of 6) [1/17/2002 2:30:50 PM]
