[Moon-net] [Moon] 2.40m dish
Koellner, Guenter (NSN - DE/Munich)
guenter.koellner at nsn.com
Fri Sep 26 08:36:49 CEST 2008
consequently following the latest steps in feed-design, all the good ones are designed for f/D=0.37 or bigger, as there are RA3AQ, OM6AA, Super-VE4MA and latest N2UO.
In my opinion all the feeds for deep dishes are lacking performance. If not, tell me which is equal. Yes, chapperal choke, that is what I am using, but unfortunately not with the same efficiency, and also with some problems according to circularity at the outer part. Having 12dB sun noise with 0.35dB preamps on 23cm as well as on 13cm is in my opinion meanhwile a good value, but I do not know what else to do in order to increase it significantly. But I am open for suggestions.
Just on EME we are trying to catch the even the last tenth of a dB out of our dishes (as SM5LE's tests and G3LTF's results nicely proove), and with a small dish, one has to consider every point in order to get it. I also want to emphasize a statement of G3LTF, who recently mentioned that probably some of the bigger dish owners are simply not picking out the maximum of their equipment, just because they hear already enougth. Peter's tests show that even then there is a possiblity of improvement.
And with a marginal dish one can really do EME nicely, but be aware that you must not waste efficiency.
73, Günter (dl4mea)
BTW, my callsign is DL4 M E A and not DL4 M A E.... I think that this most probable comes from DL5MAE, who's callsign is quite similar and probably somewhat more popular. I'm wondering if Wolfgang becomes recognized as "MEA" sometimes...
And it is not DL4GA, as often understood in CW, even since I try to leave a long pause between the M and the E.
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