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echo: ham_tech
to: HANS SEIPKA
from: ROY WITT
date: 1997-07-09 08:08:00
subject: LP - Antennas

Hello Hans.
07 Jul 97 19:25, Hans Seipka wrote to Any HAM:
 HS> Hello Friends out there !!
 HS> Some time ago there have benn posted some files about LPAntennas
 HS> ...... I had a diskcrash and lost all files ...... :-(( Could anyone
 HS> send them again please ? You really would help me a lot. Many tnx 4
 HS> reading this msg. 73's es 55's de Hans OE3SSS @ OE1XAB.#OE1.AUT.EU.
 HS>
LPA Series - 222-225 MHz
USE:  Amateur Band 1.35m.
Note: See ARRL Antenna Handbook under LPA construction
Tau = 0.98
Sigma = 0.18714
B = 1.0135
COT alpha = 37.428
BAR = 1.2153
Bs = 1.2317
Lambda max = 4.4324
Lb = [0.25(1-(1/Bs))COT alpha)Lambda max] = 8.4-ft
N = 1 + (log Bs / log (1/Tau)) = 12
The following are in inches, two of each required (L)
-+----------------------------
 L1 = 14.20               d1,2 = 9.956
 L2 = 13.93               d2,3 = 9.757
 L3 = 13.67               d3,4 = 9.562
 L4 = 13.42               d4,5 = 9.371
 L5 = 13.17               d5,6 = 9.184
 L6 = 12.93               d6,7 = 9.000
 L7 = 12.69               d7,8 = 8.820
 L8 = 12.45               d8,9 = 8.644
 L9 = 12.22              d9,10 = 8.471
L10 = 12.00             d10,11 = 8.302
L11 = 11.75             d11,12 = 8.136
L12 = 11.55
Zt =6.6686  Sigma' = Sigma/sqrt Tau = 0.189
Ro = 50
Zav = 223.024 (interesting for the frequency is being used at!)
Zo = Ro^2/(8(Sigma'(Zav))) + Ro(Sqrt(Ro/(8(Sigma'(Zav))) + 1) = 57.9607
Gain = 11.0 dBi
S can be calculated from the ARRL Antenna Handbook.
Next is the 2m LPA.  Element attachment will be after the 6m
posting.  SEE BELOW!!!!
*************************************************************
*    NOTE: The boom on all these LPAs is 1-inch diameter.   *
*    All elements have a 0.9-in adjustment in the length    *
*    to compensate.  Sorry about that.  The Freq file will  *
*    have the proper statement put in.                      *
*************************************************************
-WS
... Tiny Yellow Stream,  by I. P. Freely.....
---------------
* Origin: KB6PI's Antenna Farm * San Diego, CA (1:202/909.10)

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