DSS Dish

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JdOwNj
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DSS Dish

Post by JdOwNj » Sat Feb 02, 2002 5:51 pm

I have one of those little Tiny DSS dishes... where i live, its not really adaquite... I have a large PrimeStar(anybody remember them?) dish... the 36 inch ver... could i use that dish with the dss sys?

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Chris Smith
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Re: DSS Dish

Post by Chris Smith » Sun Feb 03, 2002 9:27 pm

Yes, but you need to know about lens's and focous. The original signal "should" be adequate but if it is some how weak, any larger dish will improve the signal gain if you properly place the feed horn of your old dish into the exact focal point for that new dish. I would make up a jig with a pointer showing the original point of focous so that when you remove the old LNA you have a exact point of reference. Also the focal point isn't where the plastic cover, covers the LNA, but rather its some where inside the horn, which may be two inches [?] down inside the LNA on the old, while on the DSS model its four inches inside. Make sure you take this focal plane into account by removing both covers and measure the focal plate or wire to rim distance and adjust as necessary. One inch out of Focous may loose 50 percent of your signal strength or more. Accuracy of placement should be less than 1/8 inch or less in any direction from the original placement.

Dean Huster
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Re: DSS Dish

Post by Dean Huster » Mon Feb 04, 2002 9:38 am

If you point the dish directly at an audio noise source, maybe a boom box playing 40 or 50 feet away, you can use a microphone and small amplifier to locate the focus if the dish is of the solid (vs. mesh) type, which I assume it is. That used to be an embarrassing problem with dish installers of the larger 8' and 10' solid types. They'd be working on an LNA and telling dirty jokes while standing right there at the focus and since the dish was pointed horizontally at the time, it would beam the joke straight out and could be overheard by passersby for quite a distance.<p>The Omniplex in Oklahoma City had a couple of 12' dishes facing each other across the auditorium's diagonals and two people could carry on a conversation in a whisper in that huge room filled with noisy kids.
Dean Huster, Electronics Curmudgeon
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).

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Ron H
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Re: DSS Dish

Post by Ron H » Mon Feb 04, 2002 10:35 am

Seems like it would be difficult to know when you have the dish pointed directly at the source, especially with offset feed dishes (of which the Primestar is one example). I found this illuminating article
http://www.w1ghz.cx/antbook/chap5.pdf<p>This talks mostly about the 18" RCA dish, but there is a mention of the Primestar dish, and it seems to me the same principles would apply.<p>This article is somewhat complex, but a persistent hobbyist should be able to comprehend it.<p>Ron H<p>PS I can't get the URL to work when I click on it, but copy and paste seems to work OK.<p>[ February 04, 2002: Message edited by: RonH ]</p>

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frhrwa
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Re: DSS Dish

Post by frhrwa » Mon Feb 04, 2002 3:25 pm

no... I don't think you can use the old one because its polarized if I'm not mistaken... unless you want to try to get into government satelites.. the newer dish (satelite) like DishNet and Direct are a complete different downconverter. :confused:
JESUS”…… don’t leave EARTH without HIM!

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Chris Smith
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Re: DSS Dish

Post by Chris Smith » Mon Feb 04, 2002 4:23 pm

Wyne....The plastic dish is not polorized, its the feed horn/LNA that is polorized. That will be removed from the old one and placed on the new dish in the same orientation, and It works fine if you place it back in the proper focous on the new dish.

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Re: DSS Dish

Post by Dean Huster » Mon Feb 04, 2002 5:58 pm

Oops, Ron. You're right. I was back in the dark ages of the round 10-footers. That danged LNB is offset and aiming the thing would be a bit of a trick, wouldn't it? But, hey, if you COULD aim it, the microphone trick still might work ....<p>Had the dish been round and the feed was coaxial on the dish, you could have aimed the thing easily enough at the sound source using a framing square across the edges and sighting down it, first vertically and then horizontally.<p>But does one HAVE to keep the LNB at the original point vs. moving it to the center? What's the point of having it offset, anyway? Is it to get the arm and LNB shadow away from the bore of the reflector to maximize signal strength on such a small dish? Or does it force a more vertical angle of the reflector to help keep ice and snow from accumulating as readily?* I've only had DirecTV for not quite a year now, so really haven't researched the little guys much. I've always been a terrestrial TV sort until finally moving into the deep fringe area of southeast Missouri and finding that my sooper-dooper-deep-fringe antenna with mast-mounted amp, 40' tower and rotator still didn't get me good NBC reception. 'Course, neither does the dish .....<p>Oh, and Ron, the link doesn't work because it picks up a period at the end of the URL. If you go back and edit the thing and leave the period off the end of the sentence (although I don't see it) it should fix things up OK. Infopop editing or URLs requires fixing the URL in TWO places, at least on the older version of Infopop that I use all the time at antiqueradios.com<p>*Had I read Ron's reference first, I'd have answered my own question: no shadow or reduced shadow and as an added bonus, it would appear to give a more vertical attitude to the dish to help reduce the accumulation of ice, snow and avian deposits.<p>[ February 04, 2002: Message edited by: Dean Huster ]</p>
Dean Huster, Electronics Curmudgeon
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).

R.I.P.

JdOwNj
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Re: DSS Dish

Post by JdOwNj » Tue Feb 05, 2002 12:41 pm

I am slightly confused... This has the pickup unit already mounted on the dish... Can I just hook up the coax as it is? Do i need to transfer the pickup from the old dish? Does the Primestar network still exist?

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Chris Smith
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Re: DSS Dish

Post by Chris Smith » Tue Feb 05, 2002 12:50 pm

If I recall the frequency is different [2x?] from the other set. Also Im not sure about the running voltage or polarity of the other LNA both for voltage polarity and alignment polarity, etc. I would say don't even try because the load of the LNA might fry the set box? Basically they are not the same. On top of this the mounting will be completely different making this job a mechanical matching Job, not a electronic project. The easiest way to match the different LNA is the old method of three legs [allthread rods] forming a tripod which allows you to move the LNA in all three axis.<p>[ February 05, 2002: Message edited by: Chris Smith ]</p>

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frhrwa
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Re: DSS Dish

Post by frhrwa » Tue Feb 05, 2002 1:51 pm

I just went through this with a neighbor, the lnb on that dish is configured completely different, the mount or tongue for the LNB is totally different, the LNB is a polarized unit so it can't be used for the Direct/DishNet satelites, and the parabolics for the dish itself would require quite a bit of work in lining up the LNB should you get it to mount... easier to find a 30" round if you need the size, at least the LNB's on most of those will work, but... since you probably want the second satelite, you'll probably have to swap out the LNB's anyway...
JESUS”…… don’t leave EARTH without HIM!

Ron H
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Re: DSS Dish

Post by Ron H » Wed Feb 06, 2002 6:58 am

Here is the info you need.<p>http://www.echostaruser.org/ekb/70.htm<p>Ron H

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