Recent content by franksanderdo

Hi JanH usually those ordinary LNB have a f/d of approx. 0.6 to 0.65 depending on the manufacturer I hope this helps? Best wishes for the new year ;-) Frank

Hi folks, as fta-elite said: Offset antennas are just a section of normal parabolics. The trouble you get is the exact positioning of those antennas. As you can see in fta-elite pictures you end up with a certain overlapping which makes the positioning almost impossible. But writing this I hav...

Hi JanH you want to do multi focus with 1 LNB? That wil be difficult as I believe you will end up with some disturbance. See you aorund Frank

Hi JanH Subreflectors on in offset Multifeed are not that much another issue, but thos are very hard to kalkulate (at least for me ;-) ) As I said it is a bit tricky to modify a prime focus dish for holding the LNB. I was lucky with my 1.4m as there was the structure of the disk and the mount...

Hi Jan, sorry, picture (at this moment) is not possible as the 1.4m had to give place for a 2.4m. Even though I am planning to give the 2.4m a secondary reflector I simply did not have any time to do so during the last months. About your second question I am not sure what you are asking for. I...

Hi lnb15k I have done some trials with secondary refeloctors on one of my dishes and found the following: 1. You can improve a little a poorly focussing large dish. 2. It is some effort as you have to find the best "focus" of the large dish, and than produce a secondary fitting to that. 3...

Hi fta-elite, even though it does not look like in first view: The results are very good!! Testing on Ku is hard stuff for a home made dish as Ku needs accuracy down to a millimeter. There are a lot of 180cm factory made (segmented) dishes which can not get close to a 90cm dish. Your results...

Hi fta-elite, this looks like an interesting approach. Especially for C Band I believe it is very good. Can you give some description how you made it? Which Materials have been used? Do I read the drawing right that the dish is +- 2m dia? Well done!! See you around Frank

Hi and Hello, well, some test further I can say: 1. The "Focus" of the Dish is about 9 cm closer to the Dish than the original support suggests ;-) 2. To talk about Focus is some how exaggerating. it is more a 10cm2 area. 3. With a quickly produced template I learned the shape of the Dish is...

Hi and Hello, I have spend today some money and replaced the 1.9m with a 2.4m dish. not yet self made as I wanted to find out first what the problem with this segmented dishes is. The result is not really good ;-) In fact the new 2.4m is worse than the 1.9m. Reason is the shape of the metal...

Hi, looking at it a square one will work, but the "used" surface will only start some what inside. Please be carefull with the material selection and the pressure. With the volumes we are talking about it gets dangerous very quickly. A bursting membrane can easily do severe harm. about the...

Hi JanH The main Problem with using a combination of dishes is to get them aligned in a way that the reflection of one dish is not eliminating the reflection of the other. Means the dishes have to have EXACTLY the same distance to the feed and the last but not least the EXACTLY the same...

Hi Folks, I will try to gofor a 3m one. As I was reading all the thread I am stunned by all the diferent aproaches. A bit confused which one might be best :confused: At this moment I am thinking on a mixture of the "vacuum" and PU Foam. to be excact I am thinking about presurising a plastik or...