24 hours later. And I have done a bit more re-design and testing. Lets see what we have now. Part 1 • #48 UHF homebrew duple... Website discussion gokarters.com/s...
Amen, to the "not as many hams doing this stuff [building their own equipment]". I really enjoy building my own stuff, and repairing friends' equipment. But, I just wish there were more people like you sharing the knowledge with us newer hams. The guys with the knowledge and experience are slowly disappearing, or just don't want to share it. The information you put in these videos is priceless in my opinion. And I can't speak for anyone but myself, but that said, you, sir are very much appreciated. Thank's so much.
Thanks you very much for your kind words. I agree that there is not enough information being shared. I will continue to do my part. Thanks for watching.
Nice job Buddy! I look forward to seeing the result of 4 or 6 of them. If you find the signal is getting a little jittery, you may need to use de-caffeinated coffee cans though :^)
I'm like you Buddy - to me the best part of ham radio is building and fixing. Like Mike commented, I still have parts collected from many years ago. I have parts from a crystal set I built in cub scouts over 60 years ago! 73, Bill.
+rollerbald You are telling your age Bill :p I always keep stuff I pick up. Running out of room. And yes, more to ham radio then picking up a mic and talking. Thanks for stopping in my friend.
Tip for soldering galvanised steel is to grind all the galvanising away, then flux it immediately then solder it. If possible use a torch, brazing rod and borax flux, that always works on steel to brass. Best is to use plumbers hard solder and a torch for those joins into the can, the regular solder will break with time. Just use plumbing paste flux and wash afterwards with a scrubbing brush and baking soda to get the residue off, as it will corrode the brass and eat through the tin plate. Wonder if I could roll the can out of brass shimstock and make it, then silver plate it afterwards.
+SeanBZA Very nice tips. I did find that coffee cans do not like heat from a torch, warps very quickly. I rather use silver solder on the can but don't want to use that up just for testing purposes.Brass shim stock or even copper will work just fine for rolling your own cavity. I have seen this done on a 6 meter repeater. You could roll several layers on it with no problems. Would make a nice cavity. Thanks again.
Necessity is the mother of invention! Will be interesting to see how you source the double shielded cables for the can interconnects. Thanks for sharing along the way! 73 - Dino KL0S
+Dino Papas LOL, I need sleep! over24 hours at this. Feel like a school boy again. Double shielded eh? Somewhere amongst all my junk I should have about 20 feet of double shield from Tesco. Just have to find it. Take care my friend.
Im like you Ham radio always to me was about doing things and projects not just sitting in a chair and making contacts all day the video you have is very informative i know a ham that made some duplexer out of paint cans years ago but dont remember cutting the cans down and they tuned up really good......
Yes, That is what ham radio is about. Trying things and learning from it. I have heard of folks using paint cans, shell casings and about anything you can imagine over the years. Thanks for the comments.
when I was watching your video yesterday, I said the words "use all thread!" LOL must have heard me! LOL Beautiful design, I love it! can't wait to see the ole girl go. Im jealous, I am out of coffee right now! ;) 73!
+DENNIS N No problem Dennis. Yes the all thread worked out very nice. Wish it was brass AT but could not find it locally. Will be several weeks of testing on this. Thanks for watching.
they make brass tubing for lamps its 1/8 in fine threads for the old lamp sockets I used to buy it in long pieces fine threads would make precise tuning just a thought
Nice job. The screw adjustment is a lot easier to use. Your BNC T's and all the other goodies will be headed your way Monday. LOL, throw away, what does that mean? I still have parts radios I got before I turned 10. 2 pole barns and 2 garages later and I still don't have enough room for all my junk. Just never know when you might need that widget you got 35 years sgo. :)
+MikesRadioRepair Thanks Mike. I like the adjustable screw over the slide. Works much better. I hate throwing things out. Really need to. So little space left. My garage is useless.....Cant wait to get the package.
+The Radio Shop In clinical terms its known as flat surface syndrome. Those afflicted with this syndrome can't stand to have any exposed flat surface and feel compelled to cover it with useless junk as quickly as possible. Friends and family that think we have completely lost it are frequently surprised when they need a widget at 2AM Sunday morning when all the stores are closed and find that we seem to have the entire planets inventory hidden away. Its junk until they need something. :)
that is a great upgrade Buddy thats what experimenting is all about. i fully agree ham radio has changed there arent as meny people willing to have a go at repairing or even modifying stuff these days. im the same as u i like takeing it all apart to see how it ticks lol
I agree most things are discovered through experiment and tinkering around on the bench. I like the planning aspect as well such as how and where are my antenna's going to go, which one is best for my application. etc... Nice work. 73 de K7TIE
I am impressed! I have got to get me one of those service monitors! Of course I am wanting a spectrum analyzer with tracking generator. It would sure be great to build a couple set's of these cans! One place we plan to install a UHF machine is fully climate controlled, and these would probably get the job done! It sure as heck doesn't hurt to try! I am also impressed with your lab, you have quite extensive test equipment and knowledge on their use! I have been a ham 25 years, NEVER been a "Appliance operator" but am now very interested in full repair and diagnostics. For example my recently acquired antique Kenwood TM-221A Worked great until it didn't, well ok most Kenwoods go nuts when their 2032 battery get's weak, so I went in carefully replaced the 2032 battery, reassembled most of the way, powered up and the radio is no longer working. Turn on and in almost every power up, it freezes, sometimes you can push a couple buttons but then it will freeze up within seconds. So I guess it's going to get buried in a pile till I have a service monitor like that IFR to do some signal tracing and readings. I had read the VXO may need adjustment, but I only have a DSO Scope , I am not sure how to apply to that rigs issue to see if its aligned where it needs be, I can see being a 1989 radio it could probably use a full alignment with its new memory battery. Just a thought, any tips? I subscribed and will look forward to more of your channel, this is the kinda stuff I love, I would rather watch you build coffee can duplexers than about anything my TV has to offer. 73 de Seth - W8FG
Hi Seth. First thanks for you kind words and sharing your information. Sorry taking so long to get to this message. So many here. Ok I have a question that may sound stupid but here goes. Did you do a full reset after the battery replacement? Sometimes there is so much garbage in the cpu it goes crazy. As far as an alignment that should not be needed. These rigs are fully processor controlled. So any alignment would be like audio, frequency error, PLL voltage, power out, ect. Another problem may be the electrolytic capacitors. I think this would be a great radio to learn a lot from. Also remember that you do not need all this flashy test gear. The IFR is nice yes but I use my HP8640B more than it and I also have a stand alone B&K spectrum analyzer with tracking gen. Shop around and only get what it takes to do the job. You can always upgrade later on. A Motorola 2100 series service monitor can be had for like 500 bucks. Thanks for stopping in and stay tuned.73 Buddy
I did do a reset according to manual, Im confused because the radio worked perfectly (except for memory retention of course". I expected a simple battery swap to do the job. I had read the vxo could be off to cause this behavior. Im just unsure how to go about testing as I dont think i have all necessary test gear? I am going to look and may get brave and try. Will post back here if im successful.
I remember seeing a website that was for building 6 meter duplexers with scrap sections of 1 5/8" heliax. They also had a link to a calculator that would determine the overall length needed for each cavity. I tried VHF and UHF frequencies in this app and it gave me lengths needed. Here is a link to the app, www.qsl.net/kf6yb/duplexer.html Scroll to bottom of page.
Great video and easy to follow along. I would love to build some for my UHF repeater using 1L paint tins that are readily available here in the UK. Have you put them into service and how well have they been working? Is there anything you would change?
Hello Buddy, nice cavity's. With that amount of coffee you will be awake for a long long time hi. I agree with you that the fun is in discovering how things work. How you can repare your own stuff. In the old days you had to build your own stuff because it wasn't there. It's now for the taking, with enough money. I am not that old. But i talk to these oldtimers and the "bug" comes a live. But everybody has to do his own thing. Looking forward to watch the repeater up and running. How do you fine tune without a tracking generator. Will you use a receiver? What flux are you using. Have fun and you should see my bench hi. Best 73 Henk
+FEY Yep, I have drank quite a bit, and have tons more :) Tune with signal gen, SA and a receiver with s-meter. Only way I can do it. I do plan on taking this to a buddy to have properly tuned. Then we can get the real numbers on it. Thanks for watching.
How much power can the cans take? Could these work on a 75-100 watt repeater? You have really sparked my interest, I just dont have a service monitor to help me do this
This videos is quite interesting. I have always wondered how they are made and work. Another question that is not related to this video. Thi squestion is about the Yaesu FT 747GX and the question is where do you get the replacemnet capacitor kit from. I found a couple kits on eBAy one from from Canada and the other from Hong Kong. I also wonder where I can get a kit for the Kenwood TM 2550A 2 meter transceiver. Thanks you for your help. Randel Stuckey N4OHO
I cannot ever remember seeing a kit for that radio. So download the parts list and start from there. I will see if I can do a bit of research on it. Thanks
I'll check on that since I already downloaded the service manual for that radio and it has the parts list in it. There are two sellers listed on eBay showing a kit for the radio. One is from Ontario, Canada and the other is from Hong Kong. The one from Canada sells for $39.99 and the one from Hong Kong sells for about two dollars less, but the one from Canada looks like the type of caps that you use in your recapping projects. Anyway I got the unit in today and come to find out this unit looks like the 747GX and says that it is but it isn't as deep as the one I saw you repair or use on your bench. This unit was listed as the Yaesu FT 747GX CAT system and from what I see it is just a control head and not the whole radio so I just wasted around $150 on this deal, oh well that is the way the cookie crumbles somtimes. If you have seen what this unit plugs into please let me know since I don't know anything about this unit at all. I do know that it uses a cable that has a male printer plug on either ind, which is a 36 pin plug. The unit doesn't look too bad has a couple scratches on the metal cover on the back and a couple smudges on the faceplate, not scratches just finger smudges is all as far as I can tell. Oh well my search goes on for a good cheap rig to get back on the air with. 73 and take care. Keep up the good work on the videos. Randy N4OHO
+danny blackhorse The paint it self really will not do anything. Unless it is very conductive paint. That is why they plate them with silver. Helps keep RF from leaking out Thanks for commenting
Really enjoyed the hands-on building of this! Now the fun begins coming up with the inter-cavity cable length determinations! Thanks!
Amen, to the "not as many hams doing this stuff [building their own equipment]". I really enjoy building my own stuff, and repairing friends' equipment. But, I just wish there were more people like you sharing the knowledge with us newer hams. The guys with the knowledge and experience are slowly disappearing, or just don't want to share it. The information you put in these videos is priceless in my opinion. And I can't speak for anyone but myself, but that said, you, sir are very much appreciated. Thank's so much.
Thanks you very much for your kind words. I agree that there is not enough information being shared. I will continue to do my part. Thanks for watching.
Nice job Buddy! I look forward to seeing the result of 4 or 6 of them. If you find the signal is getting a little jittery, you may need to use de-caffeinated coffee cans though :^)
+Mr Carlson's Lab Man you crack me up. That was a good one Paul. As I read that I was like ok more then the punch line. Good stuff. Thanks my friend.
I'm like you Buddy - to me the best part of ham radio is building and fixing. Like Mike commented, I still have parts collected from many years ago. I have parts from a crystal set I built in cub scouts over 60 years ago! 73, Bill.
+rollerbald You are telling your age Bill :p I always keep stuff I pick up. Running out of room. And yes, more to ham radio then picking up a mic and talking. Thanks for stopping in my friend.
Tip for soldering galvanised steel is to grind all the galvanising away, then flux it immediately then solder it. If possible use a torch, brazing rod and borax flux, that always works on steel to brass.
Best is to use plumbers hard solder and a torch for those joins into the can, the regular solder will break with time. Just use plumbing paste flux and wash afterwards with a scrubbing brush and baking soda to get the residue off, as it will corrode the brass and eat through the tin plate.
Wonder if I could roll the can out of brass shimstock and make it, then silver plate it afterwards.
+SeanBZA Very nice tips. I did find that coffee cans do not like heat from a torch, warps very quickly. I rather use silver solder on the can but don't want to use that up just for testing purposes.Brass shim stock or even copper will work just fine for rolling your own cavity. I have seen this done on a 6 meter repeater. You could roll several layers on it with no problems. Would make a nice cavity. Thanks again.
I have been a ham for 30 years and i enjoy your channel more than a lot of tech magazines that i subscribe to.
Keep up the good work.
73
Thank r the kind words
Hi matey. I used scrap gas cylinder bottles to make my 70cm Band Cavity. George 🇬🇧
Hi Buddy, great modification on the adjustment works nice now! Yes I agree that is what ham radio is for. Take care my friend 73
+TRXBench Hi Peter. Yes it works much smother now. Thanks for stopping in my friend.
Ah ok you answered my question from the last video. The rod is the course adjustment and the nut is the fine adjustment. Awesome👍
What a great video - thank you my friend :)
Necessity is the mother of invention! Will be interesting to see how you source the double shielded cables for the can interconnects. Thanks for sharing along the way! 73 - Dino KL0S
+Dino Papas LOL, I need sleep! over24 hours at this. Feel like a school boy again. Double shielded eh? Somewhere amongst all my junk I should have about 20 feet of double shield from Tesco. Just have to find it. Take care my friend.
Im like you Ham radio always to me was about doing things and projects not just sitting in a chair and making contacts all day the video you have is very informative i know a ham that made some duplexer out of paint cans years ago but dont remember cutting the cans down and they tuned up really good......
Yes, That is what ham radio is about. Trying things and learning from it. I have heard of folks using paint cans, shell casings and about anything you can imagine over the years. Thanks for the comments.
when I was watching your video yesterday, I said the words "use all thread!" LOL must have heard me! LOL Beautiful design, I love it! can't wait to see the ole girl go. Im jealous, I am out of coffee right now! ;)
73!
+su pyrow LOL, so that was you that planted that ion my head.... I have too much coffee now, must drink faster!! Thanks for commenting
Great idea much better using threaded rods, I will wait and see your complete project and then do mine,, Thanks for taking time to share this
+DENNIS N No problem Dennis. Yes the all thread worked out very nice. Wish it was brass AT but could not find it locally. Will be several weeks of testing on this. Thanks for watching.
they make brass tubing for lamps its 1/8 in fine threads for the old lamp sockets I used to buy it in long pieces fine threads would make precise tuning just a thought
Love this stuff 73
Impressive! Can't wait to see more.
+RF Burns Thanks. A lot of work with out sleep, but worth it.
Cool video, did great job fabricating that duplexer.
+Sam Iam Thank you. Wait till we build the VHF duplexer. That will be some fabricating!. Glad you liked it.
Great work. Very interesting.
Thanks
Nice job. The screw adjustment is a lot easier to use. Your BNC T's and all the other goodies will be headed your way Monday.
LOL, throw away, what does that mean? I still have parts radios I got before I turned 10. 2 pole barns and 2 garages later and I still don't have enough room for all my junk. Just never know when you might need that widget you got 35 years sgo. :)
+MikesRadioRepair Thanks Mike. I like the adjustable screw over the slide. Works much better. I hate throwing things out. Really need to. So little space left. My garage is useless.....Cant wait to get the package.
+The Radio Shop
In clinical terms its known as flat surface syndrome. Those afflicted with this syndrome can't stand to have any exposed flat surface and feel compelled to cover it with useless junk as quickly as possible. Friends and family that think we have completely lost it are frequently surprised when they need a widget at 2AM Sunday morning when all the stores are closed and find that we seem to have the entire planets inventory hidden away. Its junk until they need something. :)
Most excellent tuning mod.
Thanks
that is a great upgrade Buddy thats what experimenting is all about. i fully agree ham radio has changed there arent as meny people willing to have a go at repairing or even modifying stuff these days. im the same as u i like takeing it all apart to see how it ticks lol
+Gary g1fsh Thanks Gary. Sort of design as you go. Yep, lost art. We have to keep it going. Why I love doing this stuff.
I agree most things are discovered through experiment and tinkering around on the bench. I like the planning aspect as well such as how and where are my antenna's going to go, which one is best for my application. etc... Nice work. 73 de K7TIE
Thanks, I agree
I am impressed! I have got to get me one of those service monitors! Of course I am wanting a spectrum analyzer with tracking generator. It would sure be great to build a couple set's of these cans! One place we plan to install a UHF machine is fully climate controlled, and these would probably get the job done! It sure as heck doesn't hurt to try! I am also impressed with your lab, you have quite extensive test equipment and knowledge on their use! I have been a ham 25 years, NEVER been a "Appliance operator" but am now very interested in full repair and diagnostics. For example my recently acquired antique Kenwood TM-221A Worked great until it didn't, well ok most Kenwoods go nuts when their 2032 battery get's weak, so I went in carefully replaced the 2032 battery, reassembled most of the way, powered up and the radio is no longer working. Turn on and in almost every power up, it freezes, sometimes you can push a couple buttons but then it will freeze up within seconds. So I guess it's going to get buried in a pile till I have a service monitor like that IFR to do some signal tracing and readings. I had read the VXO may need adjustment, but I only have a DSO Scope , I am not sure how to apply to that rigs issue to see if its aligned where it needs be, I can see being a 1989 radio it could probably use a full alignment with its new memory battery. Just a thought, any tips? I subscribed and will look forward to more of your channel, this is the kinda stuff I love, I would rather watch you build coffee can duplexers than about anything my TV has to offer. 73 de Seth - W8FG
Hi Seth. First thanks for you kind words and sharing your information. Sorry taking so long to get to this message. So many here. Ok I have a question that may sound stupid but here goes. Did you do a full reset after the battery replacement? Sometimes there is so much garbage in the cpu it goes crazy. As far as an alignment that should not be needed. These rigs are fully processor controlled. So any alignment would be like audio, frequency error, PLL voltage, power out, ect. Another problem may be the electrolytic capacitors. I think this would be a great radio to learn a lot from. Also remember that you do not need all this flashy test gear. The IFR is nice yes but I use my HP8640B more than it and I also have a stand alone B&K spectrum analyzer with tracking gen. Shop around and only get what it takes to do the job. You can always upgrade later on. A Motorola 2100 series service monitor can be had for like 500 bucks. Thanks for stopping in and stay tuned.73 Buddy
I did do a reset according to manual, Im confused because the radio worked perfectly (except for memory retention of course". I expected a simple battery swap to do the job. I had read the vxo could be off to cause this behavior. Im just unsure how to go about testing as I dont think i have all necessary test gear? I am going to look and may get brave and try. Will post back here if im successful.
Keep us informed. May be able to help you through it.
I remember seeing a website that was for building 6 meter duplexers with scrap sections of 1 5/8" heliax. They also had a link to a calculator that would determine the overall length needed for each cavity. I tried VHF and UHF frequencies in this app and it gave me lengths needed.
Here is a link to the app,
www.qsl.net/kf6yb/duplexer.html
Scroll to bottom of page.
Yes I have seen that. thanks for the link for the app.
you did the same thing i was thinking on the first video :D
Remind me , what did I do lol. Been a while since I did that one :-)
Wonderful Job
+MrMac5150 Thank you MrMac. And thanks for watching.
You should use bolts with very fine threads otherwise the adjustments are too course.
Really good video,could you do a follow up on building the phasing harness please diy style
rob 73
Great video and easy to follow along. I would love to build some for my UHF repeater using 1L paint tins that are readily available here in the UK. Have you put them into service and how well have they been working? Is there anything you would change?
Thanks Mathew. They seem to work fine if used in a controlled environment. Temperature plays a big roll in these type.
Hello Buddy, nice cavity's. With that amount of coffee you will be awake for a long long time hi. I agree with you that the fun is in discovering how things work. How you can repare your own stuff. In the old days you had to build your own stuff because it wasn't there. It's now for the taking, with enough money. I am not that old. But i talk to these oldtimers and the "bug" comes a live. But everybody has to do his own thing. Looking forward to watch the repeater up and running. How do you fine tune without a tracking generator. Will you use a receiver? What flux are you using. Have fun and you should see my bench hi. Best 73 Henk
+FEY Yep, I have drank quite a bit, and have tons more :) Tune with signal gen, SA and a receiver with s-meter. Only way I can do it. I do plan on taking this to a buddy to have properly tuned. Then we can get the real numbers on it. Thanks for watching.
Line the inside of the cans with silver leaf,... Maybe test temp changes on can before and after a silver leaf is applied
Good idea, thank hil billy
i dont get it. if one can is "absorbing" Xfrequency. why do you need two in series?
to make sure nothing passes thru?
Well now 7yrs down the road, how did these hold up?
How much power can the cans take? Could these work on a 75-100 watt repeater? You have really sparked my interest, I just dont have a service monitor to help me do this
Should handle that if tuned and setup correctly. There are other ways to tune them without a SM or SA.
This videos is quite interesting. I have always wondered how they are made and work.
Another question that is not related to this video. Thi squestion is about the Yaesu FT 747GX and the question is where do you get the replacemnet capacitor kit from. I found a couple kits on eBAy one from from Canada and the other from Hong Kong.
I also wonder where I can get a kit for the Kenwood TM 2550A 2 meter transceiver.
Thanks you for your help.
Randel Stuckey N4OHO
I cannot ever remember seeing a kit for that radio. So download the parts list and start from there. I will see if I can do a bit of research on it. Thanks
I'll check on that since I already downloaded the service manual for that radio and it has the parts list in it.
There are two sellers listed on eBay showing a kit for the radio. One is from Ontario, Canada and the other is from Hong Kong. The one from Canada sells for $39.99 and the one from Hong Kong sells for about two dollars less, but the one from Canada looks like the type of caps that you use in your recapping projects.
Anyway I got the unit in today and come to find out this unit looks like the 747GX and says that it is but it isn't as deep as the one I saw you repair or use on your bench. This unit was listed as the Yaesu FT 747GX CAT system and from what I see it is just a control head and not the whole radio so I just wasted around $150 on this deal, oh well that is the way the cookie crumbles somtimes. If you have seen what this unit plugs into please let me know since I don't know anything about this unit at all. I do know that it uses a cable that has a male printer plug on either ind, which is a 36 pin plug.
The unit doesn't look too bad has a couple scratches on the metal cover on the back and a couple smudges on the faceplate, not scratches just finger smudges is all as far as I can tell. Oh well my search goes on for a good cheap rig to get back on the air with.
73 and take care. Keep up the good work on the videos.
Randy N4OHO
How much do they drift with temperature? Have you done any tests?
will a few layers of high temperature paint help prevent the changes
+danny blackhorse The paint it self really will not do anything. Unless it is very conductive paint. That is why they plate them with silver. Helps keep RF from leaking out Thanks for commenting
How much RF are you putting in to the can.....
For testing a few hundred mili-watts. I have put 10 watts through these already.
thaks to your video
i will try to make like that
you can see my video to
thanks
Good luck on the project. not too hard at all. I will check your videos.
thank you so much
terima kasih banyak
matur suwon yeh
sakalangkong