Wish I knew how to construct a circuit - I would build one of these polarotor controllers!

[anik]

Some time back I subscribed to an RSS feed from this site before I knew anything about it, anyway today a link came in to this post which I found quite interesting:

http://www.digitalhome.ca/forum/showthread.php?p=2021770#post2021770

It begins this way:

This circuit is used to convert the 14V/18V (Vert/Horiz) LNB voltage from a typical DVB satellite receiver to a servo pulse, in order to move the servo motor in a servo based C/Ku feedhorn. This along with a DMSI VBox7 to move the actuator eliminates the need to use an old analog receiver to move your old BUD dish, while maintaining the original performance of the Feedhorn electronics. Some people advocate replacing the Feedhorn with a more recent made in China Feedhorn using LNBFs. I do not think one can expect the same performance from any made in China feeds vs made in USA even if the Made in USA was designed 20-30 years ago. In a nutshell I think the recent made in china stuff is junk.
A much better solution would be to use a Chapparal ortho feed with separate H/V LNBs but that is quite expensive for residential C/Ku service (ie new C/Ku Ortho feedhorn plus 4 LNBs, 2 for each frequency band).

I had the VBOX7 in my system to control my actuator for about 6 months but in order to completely get rid of the old analog receiver from my system, I still needed a way to move the feedhorn's servo motor...

I was just mentioning a day or two ago that when I buy a new receiver (hopefully once the ice age ends here) I will probably need to buy a new feedhorn/LNB and I was definitely going to buy one of the Chinese-made ones, not because I think Chinese quality is always the greatest, but that's about the only thing you can get for a reasonable price these days. But as far as I know there is really nothing wrong with my existing feedhorn and LNB's, since they worked with my old Diamond receiver. So I would be in the same boat as the author of that post, except that I don't build hardware (unless maybe it's something VERY simple, and this doesn't look VERY simple to me).

It doesn't look like he has any desire to make commercial units or even extra PC boards, so I think I am out of luck, but I thought maybe those of you that are into building stuff might want to take a look at this, particularly if you are like me and don't have a money tree growing in the back yard. Or if you think you might have any interest, you might want to download the diagrams and plans, just to have them if you ever need them.

On the other hand, there is a part of me that thinks that maybe the Chinese feedhorn/LNBs aren't THAT bad, particularly when compared with the relatively higher degree ratings of the older technology LNB's. I understand the nostalgia of looking at an old Chaparral feedhorn and comparing the aesthetic of that to some cheap-appearing thing in white plastic, but can we realistically say that the new voltage-switched units with lower degree ratings are really any worse in actually receiving signals? Don't know but I guess I will find out.

 

[Lone Gunman]

FYI I converted from a Corotor II to an LNBF about 3 years ago and never looked back, and WON'T go back either as long as the Chinese LNBFs are as cheap as they are now. When I switched over I did an A/B test on different TPs and there wasn't a nickel's worth of difference between the two. Currently I have the "no longer available" DMX741S LNBF on both my systems and when/if those go out I'll probably be looking at the BSC621S to replace it as I do believe that the DMX I have is actually a BSC clone.

Titanium here on SatGuys has built a dish controller with a built in servo controller that will connect to the standard FTA receiver to control your BUD and Corotor feed horn. Not sure what the cost is but I'm willing to wager it's way more expensive than an LNBF and you already have the Vbox 7 to move your dish.

 

[77TA]

I have a NS741 (newer version of DMX741 I believe) and really like it. I think it performs as well as most old school lnbs.



I’d like to try the new Titanium pll c band lnbf but haven’t quite convinced myself to give up having both c and ku on the 6 footer yet. I’ll probably end up trying it eventually then deciding if it’s worth it to give up ku. If it could work a few miracles like giving me cbs and the nascar mux I would be sold.

 

[Titanium]

Ricks Satellite has been selling this type of polarity control unit for a few years. Assembled for $49 + shipping. Looks like it is suggested to also add a power inserter for continuous 18Vdc.

 

[Lone Gunman]

I have a NS741 (newer version of DMX741 I believe) and really like it. I think it performs as well as most old school lnbs.

Yeah I've got one of those NS741 LNBFs also but I'm not particularly impressed with the quality of the housing or the way it's made. It's a little too cheap for me as it is real easy to bend the housing with the set screw and the bell on the end of it has to be filed off in order to make it fit in my Chaparral scaler ring. It does perform about as well as the DMX though.

 

[. Raine]

I couldn't open the schematic diagram downloaded from that link. Downloaded twice, unzipped it and it was pdf's but popped up with an unable to open message. On the original site is the schematic and more though.... http://www.ringolake.com/pic_proj/satellite/sat_projects.html

You're probably selling yourself short, you could probably build it, Anik. It may look intimidating if you can't read schematics well, but it's really a simple circuit. A little studying of reading schematics, what components are what and learning basic soldering skills and I'd bet you'd be good to go.

 

[anik]

FYI I converted from a Corotor II to an LNBF about 3 years ago and never looked back, and WON'T go back either as long as the Chinese LNBFs are as cheap as they are now. When I switched over I did an A/B test on different TPs and there wasn't a nickel's worth of difference between the two. Currently I have the "no longer available" DMX741S LNBF on both my systems and when/if those go out I'll probably be looking at the BSC621S to replace it as I do believe that the DMX I have is actually a BSC clone.

Titanium here on SatGuys has built a dish controller with a built in servo controller that will connect to the standard FTA receiver to control your BUD and Corotor feed horn. Not sure what the cost is but I'm willing to wager it's way more expensive than an LNBF and you already have the Vbox 7 to move your dish.

I kind of figured there would not be a huge difference in performance and I actually like the idea of voltage switch better because those old mechanical polorotor units had a tendency to go bad from time to time. Since the voltage-switched units have no moving parts (at least not that I am aware of), I would actually prefer one of those.

The devices Titanium is selling are WAY too expensive for me but the bigger issue is that they require a serial port connection for firmware updates, and they stopped putting serial ports on new computers about the time that dial-up modems went out of style. And then Titanium and I got into an exchange in the thread on that unit that left such a bad taste in my mouth that I said that I would never buy one of his products, even if it were the best (or only) device of its kind. I guess you probably missed that or don't remember it, but his implication was that because I didn't currently have a working receiver I had no business commenting on his device, despite the fact that I've had a C-band dish for close to 20 years now. As I believe I said back then, people buy from people they like, and I try to avoid buying from people I don't like. 'Nuff said.

The VBOX 7, on the other hand, does not appear to require firmware updates (which is good because there is apparently no way to apply them) and in my mind that really is an advantage, plus I could purchase four or five of them for what one of the Titanium boxes costs. I would quite honestly rather have no way to update firmware at all than to have to try to make a serial port connection, but then as I noted in my original post, I am not into building stuff so I don't have some of the equipment that some other guys in here have. My opinion is that new equipment that has the ability to upgrade firmware should either be able to do it from a USB stick or from a wired Ethernet connection - I just don't understand why anyone would build a new device today that requires a serial port connection for updating. A wired Ethernet connection could give you the bonus of making the device controllable over the network. For example, in the case of a positioner box, it would be nice if in the winter I could set up a cron job to have it move to the far west position (otherwise known as the "snow dumping" position ) late each night so it would not accumulate snow overnight and so I could easily sweep any collected snow off in the morning.

I realize this is all personal preference and that some others may not care about having to use a serial port for firmware upgrades, but I suppose it depends on whether you have an old laptop with a serial port sitting around, and I don't.

As for the BSC621S, I'm not sure about that model but there is one review of the BSC621-2D on Amazon that is not real encouraging. If you do ever get one, be real careful to not overtighten the cable because it can snap the connection to the internal circuit board. I suppose that's true of all LNB's to some degree but from the sound of that review, the internal connection on those is rather flimsy, possibly because they just don't use enough solder.

 

[Titanium]

Wish I knew how to construct a circuit - I would build one of these polarotor...

Simple to place a dish in a snow dump position every night with any STB and your choice of a Gbox, VBox or ASC1 positioner. Only need the regular coax connection and no LAN, USB, serial, computer or special programming.

Set a single event, daily timer to position the dish every night to the far East or West satellite. That is all!


Brian Gohl
Titanium Satellite

 

[anik]

I couldn't open the schematic diagram downloaded from that link. Downloaded twice, unzipped it and it was pdf's but popped up with an unable to open message. On the original site is the schematic and more though.... http://www.ringolake.com/pic_proj/satellite/sat_projects.html

You're probably selling yourself short, you could probably build it, Anik. It may look intimidating if you can't read schematics well, but it's really a simple circuit. A little studying of reading schematics, what components are what and learning basic soldering skills and I'd bet you'd be good to go.

The zip file contains five files - a text file that reads as follows:

Order list for polarotor683.sch
Exported from EAGLE with DesignLink

Quantity Value Package Order code Manufacturer Manuf. Code Availability Price (from) Description
2 .1uF C102-064X133 13K6338 KEMET C322C104M5R5TA 261 0.05 KEMET - C322C104M5R5TA - CAPACITOR CERAMIC 0.1UF, 50V, X7R, 20%, RAD
1 10uF E3,5-10 23K4869 UNITED CHEMI-CON ESMG160ELL100ME11D 15986 0.087 UNITED CHEMI-CON - ESMG160ELL100ME11D - CAPACITOR ALUM ELEC 10UF, 16V, 20%, RADIAL
1 Case 62221 51R4146 1591XXBSBK 575 3.28 HAMMOND - 1591XXBSBK - enclosure - plastic
2 R141426 R141426 99H6283 AMPHENOL 222144 78 0.51 AMPHENOL CONNEX - 222144 - RF/COAXIAL F BHD JACK, STR 75 OHM, SOLDER
1 7805T TO220H 97K2637 KA78M05TU 37 0.247 FAIRCHILD SEMICONDUCTOR - KA78M05TU - IC, LDO REG, 500mA, 5V, TO-220-3
1 PIC12F683P DIL8 89H0442 MICROCHIP PIC12F683-I/P 1037 1.12 MICROCHIP - PIC12F683-I/P - IC, 8BIT MCU, PIC12, 20MHZ, DIP-8
1 2.2uH SD8 46P8723 11R222C 185 0.247 MURATA POWER SOLUTIONS - 11R222C - STANDARD INDUCTOR, 2.2UH, 1.9A, 20%
1 95F9397 LED3MM 33C1369 Chicago 95F9397 4767 0.086 VISHAY SEMICONDUCTOR - 95F9397- LED,Red/Grn
1 47K 0309/12 38K0377 FARNELL MCF 0.25W 47K 10112 0.01 MULTICOMP - MCF 0.25W 47K - RESISTOR, CARBON FILM, 47KOHM, 250mW, 5%
2 10K 0309/12 38K0328 FARNELL MCF 0.25W 10K 109916 0.01 MULTICOMP - MCF 0.25W 10K - RESISTOR, CARBON FILM, 10KOHM, 250mW, 5%
1 220 0309/12 38K0351 FARNELL MCF 0.25W 220R 16697 0.01 MULTICOMP - MCF 0.25W 220R - RESISTOR, CARBON FILM, 220 OHM, 250mW, 5%
1 10K S64W 16F7158 VISHAY/SPRAGUE T93YA 10K 10% 3025 0.739 VISHAY SFERNICE - T93YA 10K 10% - TRIMMER, POTENTIOMETER, 10KOHM 23TURN THRU HOLE
2 330 0309/12 38K0363 FARNELL MCF 0.25W 330R 17442 0.01 MULTICOMP - MCF 0.25W 330R - RESISTOR, CARBON FILM, 330 OHM, 250mW, 5%
1 7395-03 48F5269 MFSS100-3-D 2273 0.223 ITW PANCON - MFSS100-3-D - BOARD-BOARD CONNECTOR HEADER, 3WAY, 1ROW
1 8PIN DIP 14P 82K7786 SPC CONNECTORS SPC15494 7078 0.121 MULTICOMP (FORMERLY FROM SPC) - SPC15494 - DIP SOCKET, 8POS, THROUGH HOLE



70K9669 10uF 16V
46P6238 .1uF 50V
95F9397 red/green led

And four PDF files:

View attachment polarotor683_brd_mirror.pdf View attachment polarotor683_brd.pdf View attachment polarotor683_brd_layout.pdf View attachment polarotor683_sch.pdf

Are you saying you could not view the PDF files? I didn't have any problem viewing them on my system. Try the links above and see if they will display for you. If not, you could probably use an online service such as Zamzar to convert the PDF files to something more accessible. Or I could probably do screen captures and post them, but Zamzar might be a bit more accurate.

When I was much much younger I managed to put together a couple of Heathkit / Knight Kit type projects (one was an "Ocean Hopper" shortwave radio - does that date me or what?) but that was before the days of people making their own printed circuit boards. That is the part that pretty much totally mystifies me. Also, those are not exactly the most readable schematics I have ever seen, particularly the way they lay out the IC with all the connections on one side. But if I had the PC board and parts I probably could build it, assuming I could still hold the soldering iron steady enough to not make cold solder joints. Whether it would actually work after I got through is another matter entirely!

 

[anik]

Simple to place a dish in a snow dump position every night with any STB and your choice of a Gbox, VBox or ASC1 positioner. Only need the regular coax connection and no LAN, USB, serial, computer or special programming.

Set a single event, daily timer to position the dish every night to the far East or West satellite. That is all!


Brian Gohl
Titanium Satellite

That is fine if the receiver does not have a too-small limit on the number of timers you can set. My old Diamond receiver would only let you set eight timers and that was too few, so if whatever I buy for my next receiver has a similar limitation, I probably won't want to use one of those timer slots just to move the dish. Otherwise you are right, but my point was that I can envision situations where it might be nice to be able to move the dish via computer control.

Now if the receiver has an adequate number of timers AND they can be set from another computer on the local network (or if you can move the dish directly via a web interface on the receiver), then there would probably be no advantage to being able to control the positioner directly. But I don't know whether any receivers have that sort of functionality yet.

 

[primestar31]

This servo controller circuit is about as simple as it gets. I built one myself way back in 1984, and used it for years:

http://www.aaroncake.net/circuits/servocon.asp

Take note that where it says "R1" in the notes section, he meant "R5"

 

[skysurfer]

Ricks Satellite has been selling this type of polarity control unit for a few years. Assembled for $49 + shipping. Looks like it is suggested to also add a power inserter for continuous 18Vdc.

Works great (12V out auto commands the box to tune the servo to V pol, 18V out commands the box
to tune the servo to H pol, and it's repeatable so it's going to be right on H or V with each switching). I don't get why you would want to use a power inserter to have 18V all the time as this is supposed to automate the
servo polarity on a 18V/12V output current FTA receiver -- which is better than my old setup of an ancient
70 MHz LNA receiver that I used to control polarity with button pushes instead of current automation on my one Corotor II dish. The schematic for it is floating around Rick's website if you would rather build than buy one already assembled. Getting ready to build another one from parts in my junk box for my friend who has the Corotor II+ feedhorn since I think the best results are from ortho feedhorns (too expensive for him), then corotor II feedhorn with servo (what he has), and the worst are the c/ku cheap chinese combos as the C-band is great and Ku-band is crappy or readjust it to give Ku the priority to get great Ku and crappy c-band reception (a dual-band LNBF combo I would never recommend to him because you are giving up one band's performance for poor on the other and he watches stuff on both bands).

 

[Titanium]

I don't get why you would want to use a power inserter to have 18V all the time as this is supposed to automate the
servo polarity on a 18V/12V output current FTA receiver --

Sorry, should have been more clear. The 18Vdc inserter is placed after the controller to provide continuous 18Vdc to the LNB(s). Many LNBs performance is better when powered by 18Vdc.




Brian Gohl
Titanium Satellite

 

[. Raine]

The zip file contains five files - a text file that reads as follows:



And four PDF files:

View attachment 95281 View attachment 95282 View attachment 95283 View attachment 95284

Are you saying you could not view the PDF files? I didn't have any problem viewing them on my system. Try the links above and see if they will display for you. If not, you could probably use an online service such as Zamzar to convert the PDF files to something more accessible. Or I could probably do screen captures and post them, but Zamzar might be a bit more accurate.

When I was much much younger I managed to put together a couple of Heathkit / Knight Kit type projects (one was an "Ocean Hopper" shortwave radio - does that date me or what?) but that was before the days of people making their own printed circuit boards. That is the part that pretty much totally mystifies me. Also, those are not exactly the most readable schematics I have ever seen, particularly the way they lay out the IC with all the connections on one side. But if I had the PC board and parts I probably could build it, assuming I could still hold the soldering iron steady enough to not make cold solder joints. Whether it would actually work after I got through is another matter entirely!

Yeah, I couldn't view the PDF's, but the link you posted a few posts back worked for me, thanks! Looked at the Ocean Hopper there, vacuum tubes does kinda date things!

That is kinda weird the way they show the I.C. I'd assume that the numbers down the side are the chip's pin numbers. If not, then I have no idea. I wouldn't bother with making a circuit board myself, think I'd just wire it all up on perf-board and mount it in a case. I never had much patience for etching and drilling boards myself. I can kinda relate to what you're saying about holding the iron steady. I can still hold my hands steady, but my darn eyes are so bad now that I can hardly see what I'm doing and getting things to work is so, so much harder than it used to be!

 

[rooneysat]

For those that have a rotational feed as opposed to a fixed feed, does fine tuning the skew dramatically improve reception of certain transponders? How much does it help?

I was thinking about getting a corotor lnbf, but there is no controller support.

 

[Lone Gunman]

For those that have a rotational feed as opposed to a fixed feed, does fine tuning the skew dramatically improve reception of certain transponders? How much does it help?

I was thinking about getting a corotor lnbf, but there is no controller support.

Only one I can think of that would be "dramatically" improved would be some TPs on 103W Ku band as many there are 20* off skew from most others. Other than that I don't see much difference and I've used both a Corotor II and an LNBF.

There is a dish mover put out by Titanium called the ASC-1 that will control the dish and also the servo motor for skew but if you have to buy that, a Corotor II feed horn and 2 LNBs it's going to be pretty expensive.

 

[FaT Air]

What mount is your dish on??
A polar mount takes care of skew by itself. A Ku motor is also a polar mount.
Only need would be for the ~20 'offset' of the skew of Ku on 103W, but there's easier, and cheaper, ways of dealing with that.

 

[richyrich]

FYI I converted from a Corotor II to an LNBF about 3 years ago and never looked back, and WON'T go back either as long as the Chinese LNBFs are as cheap as they are now. When I switched over I did an A/B test on different TPs and there wasn't a nickel's worth of difference between the two. Currently I have the "no longer available" DMX741S LNBF on both my systems and when/if those go out I'll probably be looking at the BSC621S to replace it as I do believe that the DMX I have is actually a BSC clone.

Titanium here on SatGuys has built a dish controller with a built in servo controller that will connect to the standard FTA receiver to control your BUD and Corotor feed horn. Not sure what the cost is but I'm willing to wager it's way more expensive than an LNBF and you already have the Vbox 7 to move your dish.

Actually, the circuit only requires a few resistors; a 555 timer; a 5vdc regulator and/or wall 5vdc p.s.; and an available printer port on 98 to xp pc (ibm clone). The computer doesn't even need any operating system; just debug to assemble your code in DOS; which you then create a .com to run the keyboard commands as your operation of the 555 timer which you move the servo. These same parts or controllers (forms of robotics are found in rc cars and flying machines.