ARLA/CLUSTER: FW: Contactos com Arecibo ao vivo e em directo.

[João Gonçalves Costa]

-----Mensagem original-----
De: Miguel Aires Tinoco Andrade  
Enviada: sexta-feira, 16 de Abril de 2010 15:00
Para: João Gonçalves Costa
Assunto: RE: Contactos com Arecibo ao vivo e em directo.

Caros Colegas,

Se forem tentar o contacto, tenham em consideração que hoje eles só estarão ao alcance da Lua a partir das 16:42 UTC e perdem a possibilidade de usar a Lua às 19:32 UTC.

Amanhã, a janela será apenas entre as 17:39 e as 20:26.

The scheduled times of operation are:
April 16: 1645 - 1930 UTC
April 17: 1740 - 2020 UTC
April 18: 1840 - 2125 UTC

The operation at Arecibo is being run by the Arecibo radio club, using the call KP4AO.  The grid square is FK68OI.  They will be transmitting on 432.045 MHz, and receiving in the range from 432.050 to 432.060 MHz.  In case of heavy congestion they will tune even higher for callers.  On all three days KP4AO will start working SSB for the first 30 minutes or so of their moon window.  Then they will switch to CW to work the weaker stations.  

On April 18, if activity on SSB and CW seems light, they will switch to the JT65B digital mode.  Using JT65 it will be possible to work them with much less power or antenna.  However JT65 contacts take a lot of time, so they will only be able to work a limited number of stations in that mode.  It would be best to try to work them on CW and resort to JT65 only if necessary.  Since Joe, K1JT, will be one of the operators at KP4AO it is certain that they will be very efficient at their JT65B operations.

Aqui vão mais umas dicas :

What Equipment will I need ?

Next you need to know what kind of equipment will be needed to work Arecibo.  You will need a transceiver or transverter capable of receiving and transmitting SSB and CW in the 432 MHz amateur band.  For CW contacts, 100 watts should be enough power if you have an antenna with at least 13 db gain (db over a dipole).

For 432, an antenna with that gain is likely to be about 6 feet long and have 10 or 11 elements.  Thanks to Kent, WA5VJB, construction details of such an antenna are presented here:  WA5VJB 11 element 432 Yagi.

A number of people have asked about polarization.  Since Arecibo's dish uses circular polarization it does not matter whether your Yagi is horizontal, vertical, or somewhere between.  If you have circular polarization available, you can get an increase of 3 db in both transmitted and received signal, but  I do not know what sense KP4AO will be using so you would have to determine it by trial.  It is much simpler to just stay with linear polarization.

It is certainly possible to make a contact with less power or antenna, but there is likely to be quite a bit of competition during the limited operating time, so try to be as capable as you can.  For SSB contacts more power will be required.  For the same antenna, 300-400 watts would be a minimum to expect a SSB contact, and 800w would be better.  Of course a larger antenna will reduce the power requirements as well as making it easier for you to hear the signals from Arecibo.

Operating To work KP4AO you must first be able to hear them, so listen carefully until you have determined their frequency and current mode of operation.  Then you can start calling them when they stand by after a contact or a CQ. 

 You must operate 'split', receiving on 432.045 and transmitting somewhere above 432.050.  They will not be listening on their transmit frequency.

Since signals are expected to be strong, you can use standard RST signal reports.  If you prefer you can use standard moonbounce reports of O and RO.  Once you have worked them, please do not try to do so again.  With such a limited time operation it is important to give others a chance.  If you hear them call for low power stations, do not call them unless you are running 100 watts or less.


73's de CT1ETL - Miguel