Amateur radio station since 1993
RA3WDK `s Homepage

How make Flag and Preamplifier + some Life Hacks

You can download all info about this project as one file

 

Rotatable Flag

Bi-Directional Flag 160/80m band on Club Station RA3W

PreAmpAD8129

FLAG

FLAG

FLAG

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FLAG

For protection from water need to use acryl Plastik by CRAMOLIN

Cramolin plastik is a transparent acrylic resin designed to be sprayed on your electronics components, PCBs, wires and cables. The conformal coating forms a flexible protective film to protect your components from acids, salt, alkalis, alcohol, fungus and other tough conditions in the environment.

FLAG

How use Silica Gel for adsorb water and decrease humidity in box.

Attention - Silica Gel specifically designed for adsorb water and use far of food products! Silica gel packs should NOT GO NEAR FOOD. In addition, some types of silica gel designed to change color to indicate they water content (as in if they are full) contain several carcinogenic chemicals (cobaltous chloride)!

Silica Gel with humidity indicator - blue color - is OK , pink - need change adsorber. Adsorber is easy to recovery by heating to 100 С about 4-6 hours.

FLAG

FLAG

FLAG

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How make inductive choke in injector (150-200uH)?

FLAGFLAG

I use Home made instrument transformators for tune and measure preamplifier and balance filter

 

FLAG

Very useful thing (Core from TV CRT direction system) for making feed choke

About 12 turn of coaxial cable give 100 uH

FLAG

So much better Common-mode current chokes with EPCOS core inside

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FLAG

 

Old version Injector inside

PreAmpAD8129

First swith switches Flags (N/S flag or W/E flag for example), second swith switches the direction for each flag

(S or N for N/S Flag ... or E or W for W/E Flag)

PreAmpAD8129

Filters for preamplifier

  Spectr of preamp without filter Spectr of preamp with filter
0.5-10 MHz 160m filter 160m filter
0.1-20 MHz 160m filter 160m filter

Spectr evening with about -40 dbm level of SW BC band (with filter LPF 1.8 MHz)

Biggest level of SW BC station from west direction (power SW station in South Europe)

160m filter

Spectr from 0 to 10 MHz 1 hours before sunset (near Gray Line) with filter

to West

160m filter

to East

160m filter

Spectr of preamp with filter for 2 hours after sunset, west direction, max level HF BC station -45 db about 6 MHz

160m filter

 

Differential filters for preamplifier

160m filter

Balanced bandpass filter (BBPF) with stable bandwidth from 400 to 900 Ohm for 160 m Bi-Directional Flag and PreAmp

160m filter

Narrow Balanced bandpass filter (BBPF) with stable bandwidth from 400 to 900 Ohm for 160 m Bi-Directional Flag and PreAmp

160m nfilter 

Balanced bandpass filter (BBPF) with stable bandwidth from 400 to 900 Ohm for 80&160 m Band

160m nfilter 

Real frequency response of BPF 160m by transformer 1:9 in input of preamplifier

160m nfilter

 

BPF 160m for 800 Ohm has been simulate by Electronic Workbench

160m nfilter

LPF 160m for 800 Ohm has been simulate by Electronic Workbench

160m nfilter

LPF 80m for 800 Ohm has been simulate by Electronic Workbench

160m nfilter

Real frequency response of LPF 160/80 m and LPF 160 m Band by transformer 1:9 in input of preamplifier

160m nfilter

I recommed those LPF filter for preamplifier

160m nfilter

PreAmpAD8129

PreAmpAD8129

Before Front-End my SDR i use additional filter for 160-80m Band

PreAmpAD8129 PreAmpAD8129 PreAmpAD8129

 

Old Version injector for Bi-Directional Flag

160m nfilter 160m nfilter

Shield current choke for suppression current in shield of feed from my Magnetic Loop. About 30 db loss on 3,5 MHz for current on shield of feed to my Magnetic Loop. Very BroadBand Common-mode current chokes from 1 to 50 MHz

RF transformer with separate coil and only connection by magnetic field

Loss and SWR in transformer, look here for 1,8 and 3,5 MHz

Isolation between two coil by capacity with grounded shield of transformer

Isolation between two coil by capacity without grounded shield of transformer