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ANTENTOP- 01- 2015 # 019

Antenna for 50 and 70- MHz Band




Figure 3 Schematic of the ATU


Figure 4 Design of the ATU

Capacitors C1 and C2 were hi- Q air capacitors. Capacitor C2 insulated from the box. I managed tune capacitors of the ATU in such way that I could change working Band only with switch S1. ATU has losses only minus 0.53 dB. It was checked by ADVANTEST made analyzer.

Below you can see data from my Log for 25- 26-June, 2015. There are 29 QSOs and one QSO with CT1HZE- distance 3600- km. So the antenna works and works well. It should be used at any place with restricted conditions.


QSO  by ES4UY on 70mhz
Type of propagation: ES
Loc:  KO49CJ 
TRX: Ft-847 -60 wats  Ant: Home Made with 3.75m  Window Antenna.

Format: Call, Loc, RS/RST

The antenna is kind of Windom Antenna for 50- and 70- MHz. Length in 3.5 is a long part of the antenna counterpoise in 0.7- meter is short part of the antenna. ATU match the antenna with coaxial cable. I made ATU inside of aluminum box. Inductor was wound on a form with OD- 25- mm and contained 5 turns. Inductor was coiled by silver- plated wire in diameter 1.8- mm (13- AWG).Taps were made from 1, 2, 3, and 4-th turn. 

First tap of the inductor through a short length connected to the “hot” lead of the RF socket X1. Beginning of the inductor soldered to the ground of the RF socket X1. Taps 2, 3, 4 connected by a short length to the switch S1.

DJ7MN, JN58WH, 599/ 599:      S57LM, JN76HD, 599/559;    OK2BGW, JN89CH, 599/ 599;  OZ3ZW, JO54RS, 59/ 59;    OK2BGW, JN89CH, 57/ 57;   OK2BRD, JN99ET, 59/ 59;   PA0RDY,JO22KJ, 579/ 559; PA0RDY, JO22KJ,579/ 559;   OM5KM, JN98BG, 559/599;  HA3GR, JN86VK,579/ 599;  PA2IP, JO23VF, 599/599; SP3RNZ,  JO92DF, 559/ 559;   LZ1AG,KN22ID, 559/ 559; OK1KT, JO80CH, 599/599;  HA3GR, N86VK,  599/ 599;   SP6GWB, JO80JG, 599/ 599;  YO7BSN, KN15OA, 599/ 599;  9A2SB, JN95GM, 559/559; CT1HZE, IM57NH,55/55; PG5V, JO21, 559/ 549 ;  PA0O, JO33HG, 599/599;  PA2M, JO21IP,59/59;   ON4PS,  JO20KQ, 599/599;  ON4PS, JO20KQ,599/ 599;  DK2PH,  JO41GV, 599/559;  OZ1BNN, JO55PM, 55/ 55; OZ2OE, JO45VV, 59/ 59;   OZ3ZW, JO54RS, 59/ 59;   OZ8ZS, JO55RT, 57/59;  OZ1JXY, JO46TX,57/ 55.                                                                                                

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Last Updated:

May 1, 2016 22:16