Graham, Bob's advice is good. I might add you should recommend more antenna than you think you will need. There really is no such thing as too much antenna (or too much signal). Nothing creates a more Kohoutek like experience than marginal or no signals. I would recommend a small beam (three or more elements) as the minimum antenna. The beamwidth is quite wide and hand pointing is pretty easy. I have spent a lot of time elmering folks who thought they were going to hear and work hamsats with rubber ducks on their hand helds, or colinears on the end of 100 feet of RG-58. Be clear the antenna/feedline makes or breaks the system. Experienced operators tend to use the best antennas their space, money and other constraints allow. Just my thoughts after more than 20 years of satellite operation. 73, Joe kk0sd
From: [email protected] To: [email protected] Date: Tue, 9 Apr 2013 20:46:59 +0100 Subject: [amsat-bb] FUNcube Project - Your advice requested
Hi All,
As part of the FUNcube project we now need to urgently decide which is going to be the best type of antenna to propose for use at schools and colleges to receive the 145MHz downlink signals from both FUNcube-1 and FUNcube-2 on UKube after launch.
Both spacecraft will be transmitting approx 300mW of BPSK 1k2 telemetry with FEC – FC1- will be using a dipole antenna and will have passive magnetic attitude control. FC-2 on UKube will use a single monopole antenna and the spacecraft is intended to have active attitude control. This is primarily to ensure that the deployed solar panels are illuminated and that the face with the S band patch is usually earth pointing.
We believe that the resultant signal should be easily usable using an omnidirectional antenna but the questions is which would be the best type to use. Obviously ease of construction, cost, robustness and safety in a school environment will also be important factors as well as suitable “gain” and circularity from horizon to horizon. We envisage that some operations may be from fixed installations with the antennas mounted permanently but some will be temporary - perhaps hand held or bolted to a step ladder or similar.
We know there are many AMSAT members around the globe with great experience in this field and, we suspect, with some strongly held views. So please let us have some constructive input about which type is likely to be best for this purpose - your comments, ideas and lessons learnt will be very valuable for us.
Thanks in advance for your support
73
Graham G3VZV - for the FUNcube Project team
As part of the FUNcube project we need to decide which is going to be the best antenna to propose for use at schools and colleges to receives the 145MHz downlink signals from both FUNcube-1 and FUNcube-2 on UKube after launch.
Both spacecraft will be transmitting approx 300mW of BPSK 1k2 telemetry with FEC – FC1- will be using a dipole antenna and has passive magnetic attitude control. FC-2 on UKube will use a single monopole antenna and the spacecraft is intended to have active attitude control to ensure that the deployed solar panels are illuminated and that the face with the S band patch is usually earth pointing.
We believe that the resultant signal should be easily usable using an omnidirectional antenna but the questions is which would be the best type to use. Obviously ease of construction, cost, robustness and safety in a school environment will also be important factors as well as suitable “gain” and circularity from horizon to horizon.
We know there are many AMSAT members with experience in this field and, we suspect, some strongly held views but all constructive input would be very welcome.
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb