How about a Chapparal C-Band OMT with "studs"?
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Thanks for the pictures. From 1983 until quite recently I only worked with a teflon slab as a means to receiver circular polarization. In effect, it took a very long time before I ever received any satellite with linear transponders, everything one could receive in the early years in Europe had a circular polarization.
When I look at your fourth photograph I don't really understand what I'm looking at. The little box to the left I've also had on several of my feeds but it was always something that was unused. And then those radial looking bars within the feed, can you please explain to me what it is that I'm looking at? The last feed of coure I have too, except I stopped compromising: using a large mesh dish for Ku Band is at least for me counterproductive: there's just too much wind in our country to be able to use a turnable 10 ft dish without it slightly moving most of the time. No problem for C-Band but for Ku the opening angle of such large dishes is simply too small for stable reception. And of course mesh isn't the most effective way to receive Ku-Band signals. So my Seavey and Chapparal C/Ku feeds have been retired a long time ago.
When I look at your fourth photograph I don't really understand what I'm looking at. The little box to the left I've also had on several of my feeds but it was always something that was unused. And then those radial looking bars within the feed, can you please explain to me what it is that I'm looking at? The last feed of coure I have too, except I stopped compromising: using a large mesh dish for Ku Band is at least for me counterproductive: there's just too much wind in our country to be able to use a turnable 10 ft dish without it slightly moving most of the time. No problem for C-Band but for Ku the opening angle of such large dishes is simply too small for stable reception. And of course mesh isn't the most effective way to receive Ku-Band signals. So my Seavey and Chapparal C/Ku feeds have been retired a long time ago.
Good luck!
http://catalog.vincor.com/ProductDetails.asp?ProductCode=SV-ESA-44C
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Hi Jkara,
Thanks for this interesting information. I still have my Seavey ESR-124-H feed in mint condition laying around but I doubt if it will ever be used again. A dedicated circular dish sounds like a dream come true. However I would have to alter too much on the roof of our building to create a similar situation, it's just not really feasable thinking of the cost in relation to the gain. And speaking of cost: following your link: Price: $885.00 so I see that what you use isn't quite what one would considered to be something in the bargain-category. Add shipment to Europe and import taxes to this and you're likely to end up with a price tag slose to $ 1500,- which really is a bit much for a feedhorn, any feedhorn.
And by the way, a feed that starts with 3700 MHz is not what one needs when living in Europe where satellite reception starts at 3400 MHz.
Thanks for this interesting information. I still have my Seavey ESR-124-H feed in mint condition laying around but I doubt if it will ever be used again. A dedicated circular dish sounds like a dream come true. However I would have to alter too much on the roof of our building to create a similar situation, it's just not really feasable thinking of the cost in relation to the gain. And speaking of cost: following your link: Price: $885.00 so I see that what you use isn't quite what one would considered to be something in the bargain-category. Add shipment to Europe and import taxes to this and you're likely to end up with a price tag slose to $ 1500,- which really is a bit much for a feedhorn, any feedhorn.
And by the way, a feed that starts with 3700 MHz is not what one needs when living in Europe where satellite reception starts at 3400 MHz.
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I purchased mine used so it was much less!
I also have the ESR-124? 4-port ortho in use with a ChannelMaster 2.4m. These are commercial feedhorns as you know, prices indicative. Nice feed. As far as frequency, both feeds have captured well below the 3700. With the circular 44, seen on 40.5W when NSS-806 was there and on IS-805 (with the linear ESR-124) when satellite was transmitting way below 3700. I have not seen anything below 3700 so far on 40.5W here in the US since SES-6 was launched.
Let us know how you make out. Very interesting project!
All the best!
How I make out; in terms of the studs it's an incredible mix of results. On some frequencies and some polarizations I am seeing gains that I haven't thought possible, at others the extreme opposite including the disappearance of some foremerly very week but reliable transponders. Most remarkable but also extremely inconvenient is the fact that using this studs application can mean that per frequency the optimal polarity can be differen as much as 35 points on a scale from -90 via 0 to +90.
Of course this isn't any final judgement. After all, if one can find such extreme differences it also brings up the question if the studs application has been entered properly, both in terms of degrees as in terms of depth within the feedhorn. I wish there were some commercial company interested in doing some research on this. Because they would have the lab facilities that make it possible not to depend upon real life satellite reception which of course tends to differ depending on a lot of factors. That makes any specific measurement by definition relatively unreliable.
But one thing is for sure, there will be quite some readers interested in the outcome of this if we ever get any results that are less chaotic than present values.
Hi DK_Sat. Thanks for the pictures
Good clear pictures of ADL circular feeds are rare on the net it seems. I was curious what one looks like.Hi Paulvr
That feedhorn is a combined c/ku unit.The little box on the left is the port for the ku section of the feed.
The radial bars are two things. the yellow bars are the support structure for the ku cup. The cup is the part that has the movable (controlled by the motor on the back of the feed) ku probe (or wire if you like) in it. The copper wire couples the ku signal from the probe to the ku port.
Kevin
Thanks for your explanations, Kevin and DK+Sat. To begin with the latter, does that mean that this feedhorn is also meant to work with Ku-Band circular signals? Since recently we have the Russian Express AT-1 satellite at 56 degrees East which uniquely uses circular polarization in Ku-Band frequencies.
On the subject of "professional gear", In the late 80's Seavey teamed up with Winegard and Drake to promote a joint C-Band product for the European market. So at that time Seavey did indeed aim it's products at consumers rather than at professionals. Unfortunate for them: they assumed that Great britain would be a good base to concentrate their sales efforts on. From an American point of view quite understandable. However what they didn't realize is that whearas many continental Europeans speak several more languages, most Britons don't, you're lucky if they understand some rudimentary French. So their interests in broadcasts from foreign nations is likewise much less. At least I assume that that's the reason why they never were very succesful.
About things like feeds I can't speak from any personal experience, but I do know several producers of receiving equipment who also put out a "professional model" meaning that they use the same exact model that's used for consumers but place it in a 19" box and then multiply the price by as much as four times. For that reason I'm alsways a bit apprehensive when words like "professional" are used. The Seavey feed sure wasn't bad but when I replaced it by consumer products like the Chapparal co-rotor I didn't have the impression that I regressed to a worse product. But perhaps the paint of Seavey holds better that it's competitors, I used it for a too short period to find out.
On the subject of "professional gear", In the late 80's Seavey teamed up with Winegard and Drake to promote a joint C-Band product for the European market. So at that time Seavey did indeed aim it's products at consumers rather than at professionals. Unfortunate for them: they assumed that Great britain would be a good base to concentrate their sales efforts on. From an American point of view quite understandable. However what they didn't realize is that whearas many continental Europeans speak several more languages, most Britons don't, you're lucky if they understand some rudimentary French. So their interests in broadcasts from foreign nations is likewise much less. At least I assume that that's the reason why they never were very succesful.
About things like feeds I can't speak from any personal experience, but I do know several producers of receiving equipment who also put out a "professional model" meaning that they use the same exact model that's used for consumers but place it in a 19" box and then multiply the price by as much as four times. For that reason I'm alsways a bit apprehensive when words like "professional" are used. The Seavey feed sure wasn't bad but when I replaced it by consumer products like the Chapparal co-rotor I didn't have the impression that I regressed to a worse product. But perhaps the paint of Seavey holds better that it's competitors, I used it for a too short period to find out.
Ik know, but I was asking about de description you gave of the feed that seemed to indicate that the same thing counted for C and Ku bands which would have meant that it were also suitable for circular Ku-Band signals.
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