Polar Circle Amateur Radio Adventure

Propagation Prediction for JUNE 2004

The present sunspot cycle, begin to decline. For the last months for which smoothed

sunspot numbers are available, solar activity remained practically constant between a 

level of 106-107.This means that solar activity this coming summer may run not on very 

good conditions. Typical summertime propagation conditions are forecast for the HF amateur

radio bands during June. Optimum frequencies for DX propagation arte expected to be somewhat lower during most of the daylight hours, and somewhat higher during the late afternoon, early evening and nighttime hours, than they were earlier this spring.

Short skip openings, up to distances of at least 1900 Kms, are expected to increase considerably on all HF bands as a result of more frequent, more intense and widespread sporadic "E" ionization. 

Here you can find predictions made by ON4UN for JUNE, maybe can help you to find out

the better conditions to work.

The Bands

160M and 80M is no good at this time of the year. The sun don't set for about 2 months.

On 160 Meters intense solar absorption during this month will prevent ionospheric reflection during most of the daylight hours.

On 80 Meters High static level and few hours of darkness are also expected to restrict DX openings  on this band during June, but some fairly good one should be possible on other areas NOT ON ARCTIC CIRCLE due that sun don't set.

On 40 Meters DX Conditions are expected to decline during this month because of a seasonally high noise level, and a fewer hours of darkness in the northern hemisphere. Some fairly good openings , however should be possible to many areas of the world during the hours of darkness and sunset and sunrise periods.

20 Meters this band is expected to remain open to one DX area or another 

practically around-the-.clock during June. It should be the best Band for DX openings during

the early evening  hours, through the hours of darkness  and sunrise period. Exceptionally 

high signals levels are expected during periods of optimum conditions. Numerous and widespread short-skip openings are expected over distances ranging between 500 Kms to 3500 kms . During late afternoon and early evening hours propagation conditions should be optimum for both short skip and DX openings, resulting in an exceptionally high level of interference.

15 Meters band should be optimum band for DX openings during much of the late  afternoon and early evening hours. Good-to -excellent DX opening are forecast to most areas of the world during the daylight hours , with excellent openings expected to tropical and southern regions well into the evening hours as well. 

10 Meters. A sharp seasonal decrease is expected in a DX propagation conditions on this band

during June nad the summer months.

Learn more about Propagation

I am often asked to recommend a good text on Webs on HF propagation. Where discusses theory in a relatively simple manner, and tells how to use propagation data for predicting bands openings.  

In the past we've to found information  on books, and Magazines. Nowadays we've internet and lot of software can help us to get lot of information about the best way we can have a normal QSO with a DX station. If you have difficulty please look for any browser and check Propagation, but look follow on some links.

Propagation Data

If the amateur has in his shack a wealth of propagation charts or just on or two of them, he will be much better off than the other amateur  who doesn't have any.  By a simple connection through internet to the Institute for Telecommunication Sciences and Astronomy, you can receive regularly prediction muf's for the upcoming days and other information.

We use this discussion to record suggestions about the features that should or shouldn't be included in our software, and to engage in a public dialog regarding the merits of various requests for enhancements. Anyone is welcome to submit suggestions.

This page contains links to all of the public discussions for this project. We maintain a separate protected web for internal project discussions and notes.

Here is a good place to describe a list of your hobbies, projects or interests.

This page contains links to other Very Interesting places for this project. We maintain a separate protected web for internal project discussions and notes.

W6EL Prop^TM

W6EL Prop predicts ionospheric (sky-wave) propagation between any two locations on the earth on frequencies between 3 and 30 MHz. There is no charge for W6ELProp when used for non-commercial purposes.Download W6ELProp v2.70 (479,795 Bytes)

PFirst 5 stations on the log

Requirements Discussion

Unfortunately, for most of us, the ionosphere was not in usual  well behaved self this year, but, although we reached the poorest conditions possible for the higher frequency bands. 

A smoothed  sunspot  number of 105 is forecast for May and June. A seasonal decrease is forecast for DX conditions. While fewer openings are expected during both months.

DX propagation should be possible to one area of the world to another practically around-the clock on 20 meters. This should be the best band for DX propagation during the hours of darkness and through the sunrise period. 

Propagação

A noção de propagação das ondas cobre a presença ou ausência de factores favoráveis à circulação das ondas electromagnéticas, no espaço, de um emissor para um receptor.

Todos sabemos que estes factores são influenciados pelo comprimento de onda utilizado e e pelas condições criadas nas camadas ionosféricas.importância perponderante nas comunicações.

Com o ciclo solar em "queda" algumas das bandas que proporcionam contactos fáceis em DX passam estar mais tempo cerradas e sem condições. Se as condições de propagação são favoráveis, esses contactos DX serão possiveis mesmo quanso se dispõe  de uma potência bastante reduzida, e correlativamente, nenhuma condição será possível se estas condições  são desfavorávei8s, qualquer que seja a potência usada.  Devido a todas estas razões que acabamos de citar é necessário utilizar todos os instrumentos que nos possam ajudar a obter as informações necessárias a calcular ou a sugerir previsões que nos indiquem as datas, horas e frequências mais propícias para a comunicação rádio.

 

A estrutura da  Ionosfera

A propagação indirecta ou reflectida permite às ondas electromagnéticas terem um alcance bastante maior do que o horizonte visual. A energia HF pode assim efectuar diversos percursos de ida e volta antes de ser captad por uma antena situadas a dezenas milhares de quilómetros , estes contactos a que chamamos "DX". O sinal recolhido por uma estação longínqua será mais ou menos atenuado pela absorção pelo solo e pela perda consecutivca de potência.

As camadas ionosféricas que são assim capazes de reflectirem as ondas compôem-se de ar ionizado devido à acção dos raios ultravioletas do sol, sendo portanto condutoras de electricidade. No caso das comunicações rádio, interessam-nos sobretudo as três cdamadas inosféricas D, E e F.

D-Situada a cerca de 70 a 80 Kms

E-Situada a entre 100 e 130 Kms

F-Situada a 1500 a 4000 Kms

A presença da actividade solar é determinante nas condições de propagação. 

 

Cálculo de Previsões de Propagação 

W6EL Prop^TM

W6EL Prop é um programa que permite calcular as condições de propagação entre dois locais na terra nas frequências entre os 3 e os 30 MHZ. Este programa é gratuito quando usado sem fins comerciais.Download W6ELProp v2.70 (479,795 Bytes)

 

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Last updated: Maio 29, 2004.