[amsat-bb] Re: DirecWav satellite internet useful?
ko6th_greg at hotmail.com
Tue Jun 17 22:19:42 PDT 2008
An update on my Ku dish, the result of some lite poking around. Links to pictures, below.
The receive LNB has a sticker on it claiming "11.7-12.2 ghz", so this is a bit outside of the ham band. Judging from the construction, it looks like it's circularly polarized, and is fed with about a 3/4" round waveguide. According to another Ham, it appears to have what he called a "ceramic oscillator" or something like that, feeding a mixer for a low-gHz IF. He guesses the IF out is in the 1 to 2 ghz range. Since there's not a lot of filtering, and nothing is crystal controlled, we suspect that it should not be too hard to re-tune down to the 10-10.5 ghz range. It somewhat depends on whether the LO injection is on the high or low side, hopefully low. He's also worried if the waveguide is the right size.
The transmit side of things appears to be linearly polarized, and at a higher frequency (guessing by the constrictions in the feed pipe). I haven't opened the full Tx module (didn't have a Torx screwdriver handy), so I don't know what's under the shield inside. Outside the shield are a bunch of parts, nothing resembling a transmitter... Their website talks about it putting out a couple of watts.
I haven't opened up the control box yet.
Some pictures, below. Any additional hints would be appreciated!
The whole dish. Looking on the website, the new ones seem to be round; hopefully, they haven't changed the electronics part... http://home.wavecable.com/~ko6th/IMG_0115.JPG
Side view of some of the plumbing. LNB is at the left, and the back of the feed horn is to the right. The transmitter is piped in from below. We are guessing that the lumps in the plumbing between the "T" and the LNB is a filter of some sort, keeping the Tx from frying the Rx. The crud on the parts is the remains of a rather large wasp nest that was waiting for me inside the plastic hood. http://home.wavecable.com/~ko6th/IMG_0123.JPG
Outside of the LNB, with the round flange for the waveguide, and one of the feed probes. The other one is on the back side of the PCB, coming down from the top (up from the bottom on the next picture). http://home.wavecable.com/~ko6th/IMG_0131b.JPG
Inside the LNB, with the cover and shield removed. The feed is on the right, and we believe the LO is the round doughnut thing just to the lower left of center. There's a set screw on the shield cover that comes down over the ring, to adjust the frequency. There's one filter section in the middle that might need tweeking. The IF comes out the upper left. http://home.wavecable.com/~ko6th/IMG_0130b.JPG
Transmit module, with the inside shield still on. Haven't done much analysis on this yet... Where did I put that Torx? http://home.wavecable.com/~ko6th/IMG_0132b.JPG
So, I turn it back to you guys... Any further thoughts?
> From: ko6th_greg at hotmail.com
> To: amsat-bb at amsat.org
> Date: Tue, 27 May 2008 21:42:21 -0700
> Subject: [amsat-bb] Re: DirecWav satellite internet useful?
> Hi all,
> Well, it's been saved from the dumpster, at least for now. But, I kind of don't care much about the dish itself - it's probably a bit big /heavy for my Az/El rotor setup, though it's hard to tell with the huge steel support mount still attached. I nearly wrenched my back out carrying it over to my side yard this morning. (I think the Advil is wearing off... oow)
> But, back to the pre-amp and other electronics pieces... I found a reference to the Hughes DirecWay (not wav) service on the Web. Looks like the stuff runs in the Ku Band (11-14.5 ghz, according to Wikipedia), and has a 0.5-2 watt transmitter, depending on model. Sounds like it's possibly a good bit out of band for P3E needs, and I'm not much good with microwave hacking. Am I better off taking another two pills and putting it back on the pile, or is there a reasonable chance that I can do some simple (think "Drake") modifications to get it to work?
> Greg KO6TH
>> From: w7lrd at comcast.net
>> To: ko6th_greg at hotmail.com; kc6uqh at cox.net; amsat-bb at amsat.org
>> Subject: Re: [amsat-bb] Re: DirecWav satellite internet useful?
>> Date: Tue, 27 May 2008 17:14:01 +0000
>> Greg- They seem to be an off center feed antenna, similar to the old primestar dish of which I have been successfully using for several years. If it's free you can't beat the price.
>> 73 Bob W7LRD
>> "if this were easy, everyone would be doing it"
>> -------------- Original message --------------
>> From: "Greg D."
>>> Hi Art,
>>> The DirectWav is an Internet link - data, not TV - but good point about LO
>>> stability being an unknown.
>>> But, my base question was whether any of the pieces can be used, and it sounds
>>> like it's worth saving. Thanks!
>>> Greg KO6TH
>>>> From: kc6uqh at cox.net
>>>> To: ko6th_greg at hotmail.com; amsat-bb at amsat.org
>>>> Subject: Re: [amsat-bb] DirecWav satellite internet useful?
>>>> Date: Mon, 26 May 2008 22:20:55 -0700
>>>> These dishes are used on 10 GHz and lower frequencies. Designed to operate
>>>> in Ku Band ~12 GHz they will give ~30 dBof gain. The LNB and feed can be
>>>> used , at least the LNA section. As the intended use is television the LO is
>>>> not stable enough for Amateur Satellite work.
>>>> ----- Original Message -----
>>>> From: "Greg D."
>>>> Sent: Monday, May 26, 2008 8:23 PM
>>>> Subject: [amsat-bb] DirecWav satellite internet useful?
>>>> Hi folks,
>>>> My neighbor appears to be tossing their Hughes "DirecWav" satellite internet
>>>> dish and associated dish-mounted electronics. By any stroke of luck, is
>>>> this stuff reasonably convertable for use with any of the the proposed P3E
>>>> up or downlinks? I have no idea what frequency it runs. It appears to have
>>>> both transmit and receive capabilities (based on the warnings posted).
>>>> There are no model numbers tha t I can find on the electronics.
>>>> I've got my AO-40 S-band receive setup, but nothing for the higher bands.
>>>> Greg KO6TH
The i’m Talkathon starts 6/24/08. For now, give amongst yourselves.
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