Thanks, wanted to see how the IR looked on GRB Imager. The image you uploaded is how the satellite sends them in transmission (a negative), I uploaded the inverted B/W version as it would be normally seen.
GOES 16 GRB downlink vs GVAR
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Which way (negative or positive) would be the most convenient for the IR Bands? It is a simple 2 minute change to the code either way.
Like I uploaded. Clouds white and ground black. That's always the way I have viewed them. Thanks.
As I said I would, here is the first few pages of constructing the septum feed. Any changes that will need to be made will be made later in another post.
N6BY has dimensions of a septum feed that he uses, his dimensions would work for this as well. This feed is converted from the RA3AQ septum feed.
Tools
Tin snips (straight blade style)
Stainless steel wire brush (must have)
Step drill
Drill bit set, includes fraction sizes
Centering punch
Pencil (something to write with)
A caliper (can use a ruler)
Mill file (8 - 10") (needle files if available)
Clamps (small quick grip and or small C clamps)
Alligator clips
Propane torch
Needle nose pliers
Screw driver (Phillips and straight blade)
Sliver based solder and 40 or more Watt soldering iron
Helping hands device (to hold part to be soldered)
Materials
4-40 S.S. screws 1/4" long
4-40 S.S. Nuts
2-56 S.S Screws 3/16" long
2-56 S.S. Nuts
2 SMA Panel mount connectors
RF Connection part #SMA-RFC19-13
3/32" Brass tube (K+S metals)
Super alloy 1 from Muggy weld (starter kit 3/32")
Aluminum parts
2 waveguide channels, 15 1/2 X 5 1/2" .040" sheet
Manufacturer for my feed parts
Puritian Mfg.
Omaha 402-341-3753
Salesman: Mike
Any metal mfgr that carries aluminum and that fabs it should be able to do this.
Building this septum feed is not a hard task but does require some hands on skills. Using of tin snips and drills along with propane torch are needed to make this feed. Cost is dependent on the tools and materials that are already available. The more you have already, lower the up front cost. Most dimensions are standard but there are some in decimal format. If one needs a decimal conversion
chart you can find it here.
Conversion chart
The basic cost for the septum materials are $85.00 or near this. This gets the basic parts made for the feed. This don't include any tools or solder needed to build the feed. I used Muggy weld super alloy 1 for the solder on this. The reason I used this is the low temp needed to melt
the solder at 400 deg F. There's other rod out there that melts at 800 deg F. but this heat will distort the thin aluminum material. If you are good at using it then by all means use it, but I don't recommend it. The low temp solder is fine for this job and high strength is not needed.
All holes drilled are pre punched first so that the drill bit don't wander from the hole. The punch I used is a metal pencil scribe that has a hardened sharp tip that makes an easy dimple in the aluminum for the starting of
drilling. I start with a small drill bit then when the hole is made in the material I go to the size I want for the final size.
The first step is to study the dimensions sheets so that you are familiar with them. Read through this manual as well to get familiar with the steps. This will help the assembly process move along. Once you are ready the next step is to decide which end of the channels you want to be the open end. What I did was put them together as they would be in the finished look, what I wanted was the two half's of the front to even.
If the back was off slightly that didn't bother me too much. You must also decide if you want the back plate even with the back edge or as mine set in by a 1/4". Setting it back makes the uneven half's a non issue.
in does make it a little tricky to assemble the septum and back plate as one. (later step) Once this is decided mark the crosshairs for the center pin of the connectors to be drilled using the dimensions from the drawings. Set the 2 waveguide half's aside.
Take the flat aluminum sheet (15 1/2 X 5 1/2") and mark or scribe the outline of the septum dimensions.
Start with the length of the septum then at the bottom of the sheet and work upward. There will be some excess height at the top step of the septum but that will be removed later. This sheet makes the septum and the back plate of the waveguide. The scrap parts make some of the spacers that
fit between the two half's of the waveguide.
After the septum is all marked out and everything is good then use the tin snips to cut it out.
In this picture I make my first cut length wise to separate the septum from the back plate. This cut is about an 1/8" as all are off the line made earlier.
Cutting 1/8" (open areas in the picture) makes the final cut much easier and more controllable. Set the back plate off to the side for later use.
Do the same for the other steps of the septum, making a cut for the step then cutting down from the top then remove the part. Follow with each step working up the steps until you reach the last one. Then carefully cut along the line made to get the final size. Take your time in this step as too much pressure with the snips and you'll remove more then you want. If you didn't quite get to the line in the cut then use a
mill file to finish to the final size. I don't recommend a motor tool due to the rapid removal of material that could easily take to much off.
In my cuts I found that maybe .010" of material may still be before the line so a file does the job well to remove that little bit. Or the cut didn't quite come out straight.
When you have the septum to the final size and are happy with it use the mill file to remove shear burrs and any burrs along cut edges that are sharp. Also in this step use the needle nose pliers to straighten any warped parts from the tin snips. The step corners should only have a very light file touch as you don't want to remove any material just the burrs. The above steps may be repeated a couple of times before the final product is achieved. Set part aside.
N6BY has dimensions of a septum feed that he uses, his dimensions would work for this as well. This feed is converted from the RA3AQ septum feed.
Tools
Tin snips (straight blade style)
Stainless steel wire brush (must have)
Step drill
Drill bit set, includes fraction sizes
Centering punch
Pencil (something to write with)
A caliper (can use a ruler)
Mill file (8 - 10") (needle files if available)
Clamps (small quick grip and or small C clamps)
Alligator clips
Propane torch
Needle nose pliers
Screw driver (Phillips and straight blade)
Sliver based solder and 40 or more Watt soldering iron
Helping hands device (to hold part to be soldered)
Materials
4-40 S.S. screws 1/4" long
4-40 S.S. Nuts
2-56 S.S Screws 3/16" long
2-56 S.S. Nuts
2 SMA Panel mount connectors
RF Connection part #SMA-RFC19-13
3/32" Brass tube (K+S metals)
Super alloy 1 from Muggy weld (starter kit 3/32")
Aluminum parts
2 waveguide channels, 15 1/2 X 5 1/2" .040" sheet
Manufacturer for my feed parts
Puritian Mfg.
Omaha 402-341-3753
Salesman: Mike
Any metal mfgr that carries aluminum and that fabs it should be able to do this.
Building this septum feed is not a hard task but does require some hands on skills. Using of tin snips and drills along with propane torch are needed to make this feed. Cost is dependent on the tools and materials that are already available. The more you have already, lower the up front cost. Most dimensions are standard but there are some in decimal format. If one needs a decimal conversion
chart you can find it here.
Conversion chart
The basic cost for the septum materials are $85.00 or near this. This gets the basic parts made for the feed. This don't include any tools or solder needed to build the feed. I used Muggy weld super alloy 1 for the solder on this. The reason I used this is the low temp needed to melt
the solder at 400 deg F. There's other rod out there that melts at 800 deg F. but this heat will distort the thin aluminum material. If you are good at using it then by all means use it, but I don't recommend it. The low temp solder is fine for this job and high strength is not needed.
All holes drilled are pre punched first so that the drill bit don't wander from the hole. The punch I used is a metal pencil scribe that has a hardened sharp tip that makes an easy dimple in the aluminum for the starting of
drilling. I start with a small drill bit then when the hole is made in the material I go to the size I want for the final size.
The first step is to study the dimensions sheets so that you are familiar with them. Read through this manual as well to get familiar with the steps. This will help the assembly process move along. Once you are ready the next step is to decide which end of the channels you want to be the open end. What I did was put them together as they would be in the finished look, what I wanted was the two half's of the front to even.
If the back was off slightly that didn't bother me too much. You must also decide if you want the back plate even with the back edge or as mine set in by a 1/4". Setting it back makes the uneven half's a non issue.
in does make it a little tricky to assemble the septum and back plate as one. (later step) Once this is decided mark the crosshairs for the center pin of the connectors to be drilled using the dimensions from the drawings. Set the 2 waveguide half's aside.
Take the flat aluminum sheet (15 1/2 X 5 1/2") and mark or scribe the outline of the septum dimensions.
Start with the length of the septum then at the bottom of the sheet and work upward. There will be some excess height at the top step of the septum but that will be removed later. This sheet makes the septum and the back plate of the waveguide. The scrap parts make some of the spacers that
fit between the two half's of the waveguide.
After the septum is all marked out and everything is good then use the tin snips to cut it out.
In this picture I make my first cut length wise to separate the septum from the back plate. This cut is about an 1/8" as all are off the line made earlier.
Cutting 1/8" (open areas in the picture) makes the final cut much easier and more controllable. Set the back plate off to the side for later use.
Do the same for the other steps of the septum, making a cut for the step then cutting down from the top then remove the part. Follow with each step working up the steps until you reach the last one. Then carefully cut along the line made to get the final size. Take your time in this step as too much pressure with the snips and you'll remove more then you want. If you didn't quite get to the line in the cut then use a
mill file to finish to the final size. I don't recommend a motor tool due to the rapid removal of material that could easily take to much off.
In my cuts I found that maybe .010" of material may still be before the line so a file does the job well to remove that little bit. Or the cut didn't quite come out straight.
When you have the septum to the final size and are happy with it use the mill file to remove shear burrs and any burrs along cut edges that are sharp. Also in this step use the needle nose pliers to straighten any warped parts from the tin snips. The step corners should only have a very light file touch as you don't want to remove any material just the burrs. The above steps may be repeated a couple of times before the final product is achieved. Set part aside.
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Installing SMA connectors...
I used SMA panel mount connectors for this feed. You could use "N" or BNC connectors as well but the connector layout will be a bit different and so may be the hardware to fasten it to the waveguide body. To install the connectors I find the easiest way is to drill a hole just to the center pin size so that the pin will just fit through the hole.
As described earlier use the punch here to make your drill bit stay centered in the crosshairs mark. Once the center hole is made for the connector put the connector center pin through that hole (connector on outside of waveguide body) carefully hold the connector's body while pencil marking the other 4 holes. Don't let the connector move here or the mounting holes will be off. Set connector off to the side.
Punch & then drill 3/32" holes for all 4 screw locations. Oversize 2 of the connector mount holes to 7/64" so that the is a little play, this also helps if the hole centers are just slightly off from the previous step.
Lightly clean any burrs from the holes. I use a step drill bit to finish the final center hole for the connector as these bits make clean round holes. A
standard drill bit can be used here but be careful to keep the hole round and flat as it goes through the material.
With the center hole for the pin already made I enlarge it to allow the step drill bit's tip to just fit and drill a finished size to 5/32" dia. again clean any burrs from the hole and edges.
Use the 2-56 X 3/16" S.S screws & nuts to temporary fasten the connector to the body of the waveguide. It fits, great make sure that the connector's center pin can be adjusted to be in the center of the hole. If not, figure out where you need to remove some material and go to it. but don't take too much off here. Hopefully after the 4 mounting holes are drilled you will know if the connector's going to fit at that point.
Repeat with the other half of the waveguide.
When this set is completed remove connectors from waveguide body and set back aside for later step.
I used SMA panel mount connectors for this feed. You could use "N" or BNC connectors as well but the connector layout will be a bit different and so may be the hardware to fasten it to the waveguide body. To install the connectors I find the easiest way is to drill a hole just to the center pin size so that the pin will just fit through the hole.
As described earlier use the punch here to make your drill bit stay centered in the crosshairs mark. Once the center hole is made for the connector put the connector center pin through that hole (connector on outside of waveguide body) carefully hold the connector's body while pencil marking the other 4 holes. Don't let the connector move here or the mounting holes will be off. Set connector off to the side.
Punch & then drill 3/32" holes for all 4 screw locations. Oversize 2 of the connector mount holes to 7/64" so that the is a little play, this also helps if the hole centers are just slightly off from the previous step.
Lightly clean any burrs from the holes. I use a step drill bit to finish the final center hole for the connector as these bits make clean round holes. A
standard drill bit can be used here but be careful to keep the hole round and flat as it goes through the material.
With the center hole for the pin already made I enlarge it to allow the step drill bit's tip to just fit and drill a finished size to 5/32" dia. again clean any burrs from the hole and edges.
Use the 2-56 X 3/16" S.S screws & nuts to temporary fasten the connector to the body of the waveguide. It fits, great make sure that the connector's center pin can be adjusted to be in the center of the hole. If not, figure out where you need to remove some material and go to it. but don't take too much off here. Hopefully after the 4 mounting holes are drilled you will know if the connector's going to fit at that point.
Repeat with the other half of the waveguide.
When this set is completed remove connectors from waveguide body and set back aside for later step.
Assembling the 2 half's of the waveguide
Lay the septum on one of the waveguide half's and make marks on the outside where the edges of the septum are, at this time use the drop material from the cutting of the septum and cut some 1/2" strips that you can use for spacers between the two half's. No need for the 1/8" of margin as the lines here are not as important as the septum's and the strip allows more control due to it's width. Try to keep the spacers close so that the gap is small between them. Straighten and clean up the edges of the parts so they are not sharp. Mark the parts so that you know where they will go during assembly. You may be able to use a strip or two off the back plate part for this if a longer strip is needed. If one or two is needed use it from the 5/ 1/2 length not the 5 1/4" length.
Lay these strips out and also mark their edges on the outside of the flange. With the marks made find and mark center holes for the fasteners in the flanges.
No precision is needed here just make sure that they are centered in the 1/2" flange. If you are going to use a choke/matching ring then put no fasteners 4 3/8" from the front opening and a 1/4" above and below that point. As the choke ring will be in that area.
Use the amount of fasteners that make you happy. Punch the center marks so the the flange is ready for drilling.
Put the 2 half's of the waveguide together so that they are aligned with the connector holes to the back. Line up the inside joints so the they are even and smooth and front opening is even or very close. Carefully clamp the two half's together using quickgrip clamps, small C clamps or small visegrips. If using C clamps or visegrips be careful not to clamp too hard and distort the flange. Don't try to clamp the septum or spacers in yet, all you want to do is drill the waveguide flanges. During this step the clamps may need to be moved a bit to allow for drilling. Use the pre drilling steps above to
start the holes and finish to 7/64" dia with all holes in the flange.
Once all hole are drilled remove clamps and separate the two half's. In one half only drill all holes in the flange to 1/8" dia. Go back and remove any burrs and sharp edges from the holes. I find a large sharp drill bit used by hand rotated in the hole removes and cleans the hole up nicely along with a file. Run your hands over the holes to make sure that it's smooth and burr free. In the half that still has the 7/64" holes make sure it's channel side up and put the septum back in place where it would be in the finished product and clamp it in place. Do the same with the spacers. With these clamped in place on the one half turn it back over mark the holes on the septum and spacers.
Now you have all the holes marked for the septum and spaces, again remove these parts by releasing the clamps and allowing the parts to come free. At these marked spots punch a center point with the method above and drill to 1/8" dia. The slightly larger holes here will allow for some minor septum, spacer adjustments when the two half's are back together. Now is also the time to remove the excess material from the septum top step, mark and just trim it off with the snips. Clean up the edge.
Now install the 4-40 S.S. screws & nuts. Start with the septum, with a couple and work your way to the front. Install only one in each spacer so the it will pivot in place. This will make it easier as the feed is bolted together. Keep installing screws until all are done. If the 7/64" dia holes are too tight they may have to have some slight reaming to make the screws pass through.
Also make sure that the spacers are not in the waveguide (they are even with the edges).
Slowly tighten hardware and make adjustment as needed until all are good and snug and none of the parts can move.
You now should have the waveguide with the septum installed and the spacers. Looking good now.
Lay the septum on one of the waveguide half's and make marks on the outside where the edges of the septum are, at this time use the drop material from the cutting of the septum and cut some 1/2" strips that you can use for spacers between the two half's. No need for the 1/8" of margin as the lines here are not as important as the septum's and the strip allows more control due to it's width. Try to keep the spacers close so that the gap is small between them. Straighten and clean up the edges of the parts so they are not sharp. Mark the parts so that you know where they will go during assembly. You may be able to use a strip or two off the back plate part for this if a longer strip is needed. If one or two is needed use it from the 5/ 1/2 length not the 5 1/4" length.
Lay these strips out and also mark their edges on the outside of the flange. With the marks made find and mark center holes for the fasteners in the flanges.
No precision is needed here just make sure that they are centered in the 1/2" flange. If you are going to use a choke/matching ring then put no fasteners 4 3/8" from the front opening and a 1/4" above and below that point. As the choke ring will be in that area.
Use the amount of fasteners that make you happy. Punch the center marks so the the flange is ready for drilling.
Put the 2 half's of the waveguide together so that they are aligned with the connector holes to the back. Line up the inside joints so the they are even and smooth and front opening is even or very close. Carefully clamp the two half's together using quickgrip clamps, small C clamps or small visegrips. If using C clamps or visegrips be careful not to clamp too hard and distort the flange. Don't try to clamp the septum or spacers in yet, all you want to do is drill the waveguide flanges. During this step the clamps may need to be moved a bit to allow for drilling. Use the pre drilling steps above to
start the holes and finish to 7/64" dia with all holes in the flange.
Once all hole are drilled remove clamps and separate the two half's. In one half only drill all holes in the flange to 1/8" dia. Go back and remove any burrs and sharp edges from the holes. I find a large sharp drill bit used by hand rotated in the hole removes and cleans the hole up nicely along with a file. Run your hands over the holes to make sure that it's smooth and burr free. In the half that still has the 7/64" holes make sure it's channel side up and put the septum back in place where it would be in the finished product and clamp it in place. Do the same with the spacers. With these clamped in place on the one half turn it back over mark the holes on the septum and spacers.
Now you have all the holes marked for the septum and spaces, again remove these parts by releasing the clamps and allowing the parts to come free. At these marked spots punch a center point with the method above and drill to 1/8" dia. The slightly larger holes here will allow for some minor septum, spacer adjustments when the two half's are back together. Now is also the time to remove the excess material from the septum top step, mark and just trim it off with the snips. Clean up the edge.
Now install the 4-40 S.S. screws & nuts. Start with the septum, with a couple and work your way to the front. Install only one in each spacer so the it will pivot in place. This will make it easier as the feed is bolted together. Keep installing screws until all are done. If the 7/64" dia holes are too tight they may have to have some slight reaming to make the screws pass through.
Also make sure that the spacers are not in the waveguide (they are even with the edges).
Slowly tighten hardware and make adjustment as needed until all are good and snug and none of the parts can move.
You now should have the waveguide with the septum installed and the spacers. Looking good now.
GRB Imager 1.00 has been released. You may download it at: http://naturalgfx.com/GRBImager100.zip
It now offers the option of showing state / country borders and coastlines. You can use any line color.
So all you need is a 10 foot dish, a septum like Timothy built, a TBS6983/TBS6903 or Digital Devices DVB card, 2 Nooelec Sawbirds with bias tees, a computer with 64-bit Windows 7 or 10, and this free software.
Brett,
I can't click "like" a 100 times! for that post of yours. Fantastic.
Guess I need to go out and get another machine for this.
I can't click "like" a 100 times! for that post of yours. Fantastic.
Guess I need to go out and get another machine for this.
Thanks Timothy. I decided to remove the 'Beta 2' from the name because it works as intended and is stable.
Part of this project worked out better than expected and there remain some issues which I'm currently unable to solve:
Remaining issues
1) It still needs a cable reset to get it to lock and start streaming. I spent a lot of time on this and tried many things without success.
2) The green color lookup table is a bit off, especially in dark areas and water. Dark areas don't look great. But fully lit scenes are OK.
3) I haven't figured out how to turn off the LNB power. But the bias tee has a capacitor so this shouldn't be a problem.
Better than expected
1) It's fast! It can process all the data from both streams (RHCP and LHCP) while using only about 1% of the CPU! I think any 64-bit system with a PCIe slot for the DVB card and 4 GB of RAM could easily run this program. The speed comes from the fact that its written in C and C++ (very efficient languages), and I came up with methods to handle large volumes of data efficiently and spread the workload among many threads.
If I had more time I would add the ability to output NetCDF files, do animations, show lightning strikes and make false color visualizations of the IR bands. Maybe eventually, but right now I must return to work on other projects.
.... Was looking at some early posts here -- back when I couldn't even get a signal! We have come a long ways in 11 months.
Part of this project worked out better than expected and there remain some issues which I'm currently unable to solve:
Remaining issues
1) It still needs a cable reset to get it to lock and start streaming. I spent a lot of time on this and tried many things without success.
2) The green color lookup table is a bit off, especially in dark areas and water. Dark areas don't look great. But fully lit scenes are OK.
3) I haven't figured out how to turn off the LNB power. But the bias tee has a capacitor so this shouldn't be a problem.
Better than expected
1) It's fast! It can process all the data from both streams (RHCP and LHCP) while using only about 1% of the CPU! I think any 64-bit system with a PCIe slot for the DVB card and 4 GB of RAM could easily run this program. The speed comes from the fact that its written in C and C++ (very efficient languages), and I came up with methods to handle large volumes of data efficiently and spread the workload among many threads.
If I had more time I would add the ability to output NetCDF files, do animations, show lightning strikes and make false color visualizations of the IR bands. Maybe eventually, but right now I must return to work on other projects.
.... Was looking at some early posts here -- back when I couldn't even get a signal! We have come a long ways in 11 months.
The back plate
This step starts with measuring the widest areas at the septum end of the waveguide. Due to the channel bending process, where the two channels come together may not be straight in line. The result is a slight bulge in the seam area. So measure the widest area and trim the back plate with the snips to that size. That's why I don't have any size info for the back plate as it's a trim to fit part.
From here it's try and go. Keep trimming and filing until the part fits snug not tight. You should be able to use a little pressure to push the plate in place and it should stay there on it's own, not so loose that it falls out. But not so tight that you have to use excessive force to push it in place and bend it. This step took about 40 min for me to finish. The method I used was to get one side to fit then work on the opposite side and get it to fit.
Do the same with the other 2 sides and keep working back and forth until enough material is removed to make the part fit.
If you're mounting the back plate flush with the back of the waveguide then I hope that you have already adjusted the septum in the plans at this point, the method you use is on your own as I haven't tried this yet.
Once the part fits and you get it how you want it to set, mark the septum line on the back plate so the line runs along the back of the septum from seam to seam.Remove the back plate and drill 3 holes around but no smaller then 1/8" dia. equally spaced along the line you made in the back plate. Clean up the holes so that they are smooth and burr free.
Now the interesting part.
This requires a propane torch and some soldering skills to complete this step. I also recommend that if you are using Super Alloy 1 and have never used it before that you read the instructions on how to use it and the video tips on their website for demos on using it.
It's quite easy to use (says someone who has soldered most of his life) and it really is but there are steps that must be followed to use it. Aluminum soldering is a bit tricky as the oxide layer that forms can cause many problems with joining the material, the flux that comes with Super Alloy 1 cleans and breaks that oxide layer down allowing the solder flow and to stick to the aluminum. It also tells you when the proper melting temp has been reached.
I wanted the septum and the back plate to be one part. Screws wouldn't meet my desires so the next best idea was to solder it. I admit there may be better methods but this worked for me.
First clean the aluminum area to be soldered with a stainless steel wire brush, NOT a steel brush, must be stainless steel. A regular steel wire brush will contaminate the soft aluminum. I then wipe the joint with a clean cloth afterwards. Do this to the back plate and the end of the septum.
I found that one person can't solder the back plate from inside of the feed, it just don't work. So the method I came up with solders it from the back of the feed. Use wire or something that don't pull heat away from the part that you are heating and set the entire feed on that so that it's suspended above the work surface. Put a little flux on the back plate around the holes on the septum side of the plate and reinstall the back plate being careful not to touch the areas you have just cleaned.
Get the back plate straight as much as you can across the back. This is where I use the alligator clips to hold the back plate in place as I solder it. Clip them over the edge and on top of the back plate so now it won't during the heating cycle fall out.
Begin by applying flux to the holes in the back plate then heating the seam areas on both sides and constantly working around the back side of the waveguide body, also apply heat to the back plate as you are working around the back side of the waveguide. Once the flux get it's color apply the solder rod.
In each hole apply solder, flux and heat, keeping in mind that you are still heating the back of the waveguide as you do this trying to keep the temp constant. Apply solder, flux only to the holes in the back plate no where else, the holes may fill with the solder. You may also want to use a small straight blade screwdriver to push the back plate down if it does bow a little in the middle.
It don't take a lot of solder to make the tack joint but you want to be sure that the 2 parts are joined. When you are satisfied with the result remove the heat and if you are having to hold the back plate from bowing then continue to hold it with the tip of the screwdriver until the solder cools enough to hold it on it's own. let parts cool.
After letting the parts cool take the screws out of the flanges and disassemble the feed. The septum and the back plate should be as one part now, if not then you will have to start the process all over again from cleaning. You should know by the time it cools if it bonded, mine did the first time with no issues.
Keep in mind that the part is not super brittle but the joint is not super strong (a tack joint). With the part now removed from the feed assembly the joint needs to be finished.
Once again set the septum and back plate on the wire or what ever you had the wavegide setting on so the heat is not adsorbed into the work surface. Again lightly clean the joint with a stainless steel wire brush and wipe clean, both sides of the joint.
I used a small prybar laying on the 2nd step from the top to hold the septum upright during the soldering process. What ever you use make sure that it don't take heat away from the parts and it don't move during soldering.
Apply flux to one side of the joint (the side you will be working on) and apply heat to the other side. It don't take long and the solder is molten again, apply solder and flux to the joint making a bead along the joint. If you're lucky the solder may work it's way to the other side and finish it too. If not then repeat the solder and flux process to finish the other side. let cool.
If you had a couple of blobs of solder occur (I did) then use a file to remove the best that you can. This is where a motor tool will work as well. I found cleaning the flux required denatured alcohol and warm water. Repeating the process until the part was clean. Now you should have the septum and the back plate solidly bonded together.
This step starts with measuring the widest areas at the septum end of the waveguide. Due to the channel bending process, where the two channels come together may not be straight in line. The result is a slight bulge in the seam area. So measure the widest area and trim the back plate with the snips to that size. That's why I don't have any size info for the back plate as it's a trim to fit part.
From here it's try and go. Keep trimming and filing until the part fits snug not tight. You should be able to use a little pressure to push the plate in place and it should stay there on it's own, not so loose that it falls out. But not so tight that you have to use excessive force to push it in place and bend it. This step took about 40 min for me to finish. The method I used was to get one side to fit then work on the opposite side and get it to fit.
Do the same with the other 2 sides and keep working back and forth until enough material is removed to make the part fit.
If you're mounting the back plate flush with the back of the waveguide then I hope that you have already adjusted the septum in the plans at this point, the method you use is on your own as I haven't tried this yet.
Once the part fits and you get it how you want it to set, mark the septum line on the back plate so the line runs along the back of the septum from seam to seam.Remove the back plate and drill 3 holes around but no smaller then 1/8" dia. equally spaced along the line you made in the back plate. Clean up the holes so that they are smooth and burr free.
Now the interesting part.
This requires a propane torch and some soldering skills to complete this step. I also recommend that if you are using Super Alloy 1 and have never used it before that you read the instructions on how to use it and the video tips on their website for demos on using it.
It's quite easy to use (says someone who has soldered most of his life) and it really is but there are steps that must be followed to use it. Aluminum soldering is a bit tricky as the oxide layer that forms can cause many problems with joining the material, the flux that comes with Super Alloy 1 cleans and breaks that oxide layer down allowing the solder flow and to stick to the aluminum. It also tells you when the proper melting temp has been reached.
I wanted the septum and the back plate to be one part. Screws wouldn't meet my desires so the next best idea was to solder it. I admit there may be better methods but this worked for me.
First clean the aluminum area to be soldered with a stainless steel wire brush, NOT a steel brush, must be stainless steel. A regular steel wire brush will contaminate the soft aluminum. I then wipe the joint with a clean cloth afterwards. Do this to the back plate and the end of the septum.
I found that one person can't solder the back plate from inside of the feed, it just don't work. So the method I came up with solders it from the back of the feed. Use wire or something that don't pull heat away from the part that you are heating and set the entire feed on that so that it's suspended above the work surface. Put a little flux on the back plate around the holes on the septum side of the plate and reinstall the back plate being careful not to touch the areas you have just cleaned.
Get the back plate straight as much as you can across the back. This is where I use the alligator clips to hold the back plate in place as I solder it. Clip them over the edge and on top of the back plate so now it won't during the heating cycle fall out.
Begin by applying flux to the holes in the back plate then heating the seam areas on both sides and constantly working around the back side of the waveguide body, also apply heat to the back plate as you are working around the back side of the waveguide. Once the flux get it's color apply the solder rod.
In each hole apply solder, flux and heat, keeping in mind that you are still heating the back of the waveguide as you do this trying to keep the temp constant. Apply solder, flux only to the holes in the back plate no where else, the holes may fill with the solder. You may also want to use a small straight blade screwdriver to push the back plate down if it does bow a little in the middle.
It don't take a lot of solder to make the tack joint but you want to be sure that the 2 parts are joined. When you are satisfied with the result remove the heat and if you are having to hold the back plate from bowing then continue to hold it with the tip of the screwdriver until the solder cools enough to hold it on it's own. let parts cool.
After letting the parts cool take the screws out of the flanges and disassemble the feed. The septum and the back plate should be as one part now, if not then you will have to start the process all over again from cleaning. You should know by the time it cools if it bonded, mine did the first time with no issues.
Keep in mind that the part is not super brittle but the joint is not super strong (a tack joint). With the part now removed from the feed assembly the joint needs to be finished.
Once again set the septum and back plate on the wire or what ever you had the wavegide setting on so the heat is not adsorbed into the work surface. Again lightly clean the joint with a stainless steel wire brush and wipe clean, both sides of the joint.
I used a small prybar laying on the 2nd step from the top to hold the septum upright during the soldering process. What ever you use make sure that it don't take heat away from the parts and it don't move during soldering.
Apply flux to one side of the joint (the side you will be working on) and apply heat to the other side. It don't take long and the solder is molten again, apply solder and flux to the joint making a bead along the joint. If you're lucky the solder may work it's way to the other side and finish it too. If not then repeat the solder and flux process to finish the other side. let cool.
If you had a couple of blobs of solder occur (I did) then use a file to remove the best that you can. This is where a motor tool will work as well. I found cleaning the flux required denatured alcohol and warm water. Repeating the process until the part was clean. Now you should have the septum and the back plate solidly bonded together.
Making the probes
Starting this step begins with cutting two lengths of the 3/32" brass tube to 1.30" long, I used a razor saw to do this. Use a file to clean the ends up. On the end that will not be soldered (I found) to use a drill at low speed to clean the edges up and take off the sharp cut edge. Put the tube in the chuck of the drill and at low speed run a file over that corner of the tube, careful as you can get carried away here. All you want to do is
round that edge up. If you want you can finish it with some polishing.
With that step done it's time to solder the tube to the SMA panel mount connector. To do this I used a set of
helping hands to hold the parts. The solder I used is a early version of lead free sliver solder from Kester. It was a silver, tin and copper mix. You could probably use lead based solder here but the silver solder is the best.
Dry fit the tube on the pin of the connector. You may want to slightly crimp the end of the brass tube a bit to get a better fit on the connector pin.
Clip in one of the clips the connector so the you can access the center pin. The other clip holds the tube. Tin the center pin of the panel connector and heat the brass tube so the solder can get run into the tube a bit to fill the end of it.
A 40 watt or more soldering iron should be fine for this.
Once the tube cools enough to handle take some tweezers or needle nose pliers and grab the tube with them near the end that is not to be soldered. Heat the tube again to turn the solder molten on and in it, as you do so have it near the center pin of the connector (that is still being held in the clip horizontally) and push the tube onto the connector pin. Use the iron to heat it as you do so and both the tube and pin solder will become molten.
Hold and position the tube so that it straight with the connector and also work to get it the proper length.
Continue to hold the tube with the tweezers and let it cool until is stays in place.
Let the part cool, then use a file to remove the excess solder at the base of the tube and pin. clean up part and repeat with the other connector
Installing connectors
To install the connectors is an easy task. Use the 2-56 X 3/16" S.S. screws head on the inside of the waveguide and start with one by putting the 2-56 S.S. nut on the outside. Repeat with the other three. Position probe to be in center of hole and tighten so that the connector don't move. Repeat with the other side.
With this all done now it's time to put the whole assembly back together. Again start with the septum and one 4-40 screw in the spacers. Just like the first time you put it together do so again and assemble it.
Some final touches
Now depending on if you are going to install a choke/matching ring wait for the next set of instructions on making the choke/matching ring before proceeding onward. You can still use your new feed though as you are waiting just cover the gaps up with tape or a temporary sealant.
If your are not installing the choke/matching ring then I recommend to use JB weld (link) to go in the gap around the edge of the back plate to seal it. I don't recommend to solder it as the heat required will molten the solder on the septum and could result a bad outcome. Also use some JB weld on the top seam of the wavegide to keep any water out. If you built the septum and spacers tight enough together then this may not be a problem.
I recommend to paint your feed white, why.. white is a heat repelling color so it keeps the feed as cool as it
can be in the hot sun. Aluminum expands under heat so your want to keep that low, also the cooler feed results in
a lower noise figure. Yes that does make a difference.
Use a good spray paint (Rust Oleum, Krylon or similar) to finish your feed. Put it on in several coats to make a solid thick outside shell. Of course mask the connectors so the paint stays out of them and painting the inside is not needed.
The paint does something else, the choice of aluminum body and stainless steel hardware does have it's issues.
The two metals are dissimilar and can react with each other. Especially if water (an electrolyte) is present. The result is galvanic corrosion. A good heavy coat of paint will help keep that to a min. so your feed should be intact for years to come. Unless NOAA decides to change the signal AGAIN.........
One other note: If you septum don't look quite like mine in the pictures don't be alarmed. Mine in the pictures came out 1" short. That happens when you use the 1" mark on the tape and mark it a 10.30". It comes out 1" (9.30") short. I will be making a new septum and back plate for my feed, I don't expect any change in performance.
Starting this step begins with cutting two lengths of the 3/32" brass tube to 1.30" long, I used a razor saw to do this. Use a file to clean the ends up. On the end that will not be soldered (I found) to use a drill at low speed to clean the edges up and take off the sharp cut edge. Put the tube in the chuck of the drill and at low speed run a file over that corner of the tube, careful as you can get carried away here. All you want to do is
round that edge up. If you want you can finish it with some polishing.
With that step done it's time to solder the tube to the SMA panel mount connector. To do this I used a set of
helping hands to hold the parts. The solder I used is a early version of lead free sliver solder from Kester. It was a silver, tin and copper mix. You could probably use lead based solder here but the silver solder is the best.
Dry fit the tube on the pin of the connector. You may want to slightly crimp the end of the brass tube a bit to get a better fit on the connector pin.
Clip in one of the clips the connector so the you can access the center pin. The other clip holds the tube. Tin the center pin of the panel connector and heat the brass tube so the solder can get run into the tube a bit to fill the end of it.
A 40 watt or more soldering iron should be fine for this.
Once the tube cools enough to handle take some tweezers or needle nose pliers and grab the tube with them near the end that is not to be soldered. Heat the tube again to turn the solder molten on and in it, as you do so have it near the center pin of the connector (that is still being held in the clip horizontally) and push the tube onto the connector pin. Use the iron to heat it as you do so and both the tube and pin solder will become molten.
Hold and position the tube so that it straight with the connector and also work to get it the proper length.
Continue to hold the tube with the tweezers and let it cool until is stays in place.
Let the part cool, then use a file to remove the excess solder at the base of the tube and pin. clean up part and repeat with the other connector
Installing connectors
To install the connectors is an easy task. Use the 2-56 X 3/16" S.S. screws head on the inside of the waveguide and start with one by putting the 2-56 S.S. nut on the outside. Repeat with the other three. Position probe to be in center of hole and tighten so that the connector don't move. Repeat with the other side.
With this all done now it's time to put the whole assembly back together. Again start with the septum and one 4-40 screw in the spacers. Just like the first time you put it together do so again and assemble it.
Some final touches
Now depending on if you are going to install a choke/matching ring wait for the next set of instructions on making the choke/matching ring before proceeding onward. You can still use your new feed though as you are waiting just cover the gaps up with tape or a temporary sealant.
If your are not installing the choke/matching ring then I recommend to use JB weld (link) to go in the gap around the edge of the back plate to seal it. I don't recommend to solder it as the heat required will molten the solder on the septum and could result a bad outcome. Also use some JB weld on the top seam of the wavegide to keep any water out. If you built the septum and spacers tight enough together then this may not be a problem.
I recommend to paint your feed white, why.. white is a heat repelling color so it keeps the feed as cool as it
can be in the hot sun. Aluminum expands under heat so your want to keep that low, also the cooler feed results in
a lower noise figure. Yes that does make a difference.
Use a good spray paint (Rust Oleum, Krylon or similar) to finish your feed. Put it on in several coats to make a solid thick outside shell. Of course mask the connectors so the paint stays out of them and painting the inside is not needed.
The paint does something else, the choice of aluminum body and stainless steel hardware does have it's issues.
The two metals are dissimilar and can react with each other. Especially if water (an electrolyte) is present. The result is galvanic corrosion. A good heavy coat of paint will help keep that to a min. so your feed should be intact for years to come. Unless NOAA decides to change the signal AGAIN.........
One other note: If you septum don't look quite like mine in the pictures don't be alarmed. Mine in the pictures came out 1" short. That happens when you use the 1" mark on the tape and mark it a 10.30". It comes out 1" (9.30") short. I will be making a new septum and back plate for my feed, I don't expect any change in performance.
To add to this: I left out also clean up the edges of the channels at this time, remove all shear burrs and sharp edges. Now install the 4-40 S.S. screws & nuts. Start with the septum, with a couple and work your way to the front. Install only one in each spacer so the it will pivot in place. This will make it easier as the feed is bolted together. Keep installing screws until all are done. If the 7/64" dia holes are too tight they may have to have some slight reaming to make the screws pass through
Nine months ago I posted the following:
Sure glad we didn't give up!!!!
I can't help but laugh at my post now. It appears that I was a bit discouraged back then.
Sure glad we didn't give up!!!!
I have implemented time lapse animation capability in GRB Imager. I will release version 1.1 after some minor changes to the way it works.
Meanwhile, below is a time lapse video of Hurricane Florence I made this AM. YouTube reduces the resolution but you can still see the clouds 'boiling' near the end of the video (which shifts field of view part way through).
Happy 15th anniversary, SatelliteGuys!
Meanwhile, below is a time lapse video of Hurricane Florence I made this AM. YouTube reduces the resolution but you can still see the clouds 'boiling' near the end of the video (which shifts field of view part way through).
Happy 15th anniversary, SatelliteGuys!
Thanks. .... Any chance you would be interested in manufacturing and selling septum feeds? That part is holding back many potential users. You could probably sell about 50 per year. Or is that too low of a volume?
Give me a call this week. Likely too few units for a factory run, but maybe we could brainstorm a solution.
Agreed. I think it was wishful thinking on my part that there would be enough people interested in buying a septum.
I know of only 3 other people (besides me) with fully working GRB ground stations. Another has a partially working system, and there are two others currently tweaking their systems and still trying to get their first image.
I am taking a long break from work on my "GRB Imager" program -- need to spend more time on my real job. Maybe next spring or summer I'll get back into this. Hopefully by then there will be more people with working GRB receiving systems. The software is available now and free, but getting a working hardware setup is an ordeal.
I know of only 3 other people (besides me) with fully working GRB ground stations. Another has a partially working system, and there are two others currently tweaking their systems and still trying to get their first image.
I am taking a long break from work on my "GRB Imager" program -- need to spend more time on my real job. Maybe next spring or summer I'll get back into this. Hopefully by then there will be more people with working GRB receiving systems. The software is available now and free, but getting a working hardware setup is an ordeal.
This is an infrared satellite image of California at 3 AM Friday from my GOES-16 GRB setup. The white spots show the Camp Fire in the north and the Hill Fire along the southern coast. My son decided to evacuate from his apartment in Chico late last night. The smoke was very heavy.
Its so smoky here it looks like fog. This is the worst ever — can’t go outside. I captured this image from my 10' satellite dish at noon today. No clouds over California — just smoke. It's blowing to the southwest, and I am in the middle of it.
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