#48 UHF homebrew duplexer cavity build and testing

Рет қаралды 52,087

The Radio Shop

Күн бұрын

Пікірлер: 124

@Kori114 2 жыл бұрын

Now this the ham radio I got into the hobby for! Awesome project, thanks for sharing!

@TheRadioShop 2 жыл бұрын

Glad you like it!

@brianshanahan3878 5 жыл бұрын

I always wondered what was inside duplexer cans! Thank you sir!

@TheRadioShop 5 жыл бұрын

You are welcome.

@RevGunn-jq3cq 7 жыл бұрын

This is one of the best videos I have seen on the subject! Thanks

@TheRadioShop 7 жыл бұрын

Thank you

@rollerbald 8 жыл бұрын

Good information Buddy - thanks for posting. That's the first time I ever saw a real practical demonstration of how duplexers work - I love working on ham radio equipment. Got an Icom 45A I picked up cheap at a recent hamfest that I am trying to bring back to life! 73, Bill.

@TheRadioShop 8 жыл бұрын

+rollerbald Thank you Bill. Well glad I could share that bit of first time information to you. I also just uploaded part two of this video. Good luck on the 45A, I know you can do it.

@VK6DXA 7 жыл бұрын

I never thought this could be so simple to construct. Thank you for sharing.

@TheRadioShop 7 жыл бұрын

Simple, yep. But it is very doable, thanks for watching.

@acestudioscouk-Ace-G0ACE 2 жыл бұрын

Fascinating! I'm going to check your other videos to see how the story ends.

@ffp1974 7 жыл бұрын

thanks for this video. You explained and showed how a repeater worked.

@TheRadioShop 7 жыл бұрын

Thank you very much. Glad it helped.

@MrCarlsonsLab 8 жыл бұрын

LOL, Definitely heavily caffeinated. Great Job Buddy!

@TheRadioShop 8 жыл бұрын

+Mr Carlson's Lab Thanks Paul. I am also. Was up 24 hours working on this design. Drank plenty of coffee :)

@TRXLab 8 жыл бұрын

Great project Buddy. Like to see how it is working on the air... Thumps up. Take care 73

@TheRadioShop 8 жыл бұрын

+TRXBench Yes, will be interesting how this unit performs. Still doing a bit of testing here and drinking lots of coffee!. Thanks my friend 73

@jeffbornes3986 Жыл бұрын

Simply Amazing. Thanks

@TheRadioShop Жыл бұрын

Thank you too!

@AECRADIO1 5 жыл бұрын

You can also 'roll' the tubing 'fingers' for more contact area without distorting the brass, and making an unstable contact.

@TheRadioShop 5 жыл бұрын

Good point

@blpblp-tj7ux 3 жыл бұрын

Excellent video..thank you.

@supyrow 8 жыл бұрын

That is allot of work you put into that! definitely a fun project! 73!

@TheRadioShop 8 жыл бұрын

+su pyrow Thanks Bobby. Yes lots of hours already spent just for this little bit of video. many more to come lol.

@jaybats7865 4 жыл бұрын

Such an interesting project I love it 👍

@PaulBaur 7 жыл бұрын

Thanks for sharing this, I really enjoyed it! Great information. 73's de KC9O

@TheRadioShop 7 жыл бұрын

Thanks for watching

@PowderMill 11 ай бұрын

Great video…. While it’s not going to be a real practical thing to construct for every repeater, it sure is cool! Thank you.

@PapasDino 8 жыл бұрын

Great job Buddy! Homebrew duplexers are just cool. Look forward to the final system integration. 73 - Dino KL0S

@TheRadioShop 8 жыл бұрын

+Dino Papas Thanks Dino. Another whole day spent on this and a little redesign. But I did record the redesign. So maybe post it up tomorrow. Take care my friend and thanks for stopping in.

@mikeredler4111 2 жыл бұрын

This. Is. Amazing! Well done!

@m00nst0mp 3 жыл бұрын

great video! thanks for sharing!

@TheRadioShop 3 жыл бұрын

Thanks for watching!

@dennisqwertyuiop 8 жыл бұрын

Great project, instead of tin foil , I have the aluminum tape used for hvac ducks its heaver and very sticky just run a few strips on lid,, Cant wait to see more Thank you

@TheRadioShop 8 жыл бұрын

+DENNIS N Thanks Dennis. yes the aluminum tape would work also. But I do see a problem using any type of aluminum foil or tape. Over time the seal is going to corrode since aluminum and steel will interact and cause corrosion to form. Not sure how long this will take but should be ok for a while. Probably the best method is to solder a thin steel sheet to the bottom once the unit is perfected. Just random thinking. Guess we do not see that so much since the trunk system under most houses are galvanized? Anyway glad you liked the video my friend. More to come....

@dennisqwertyuiop 8 жыл бұрын

yes just save the bottom you cut out with can opener and solder it back,, good idea

@TheRadioShop 8 жыл бұрын

+DENNIS N Now that's a thought! The big vegetable cans from a café would come that way. About the right size too.

@Sm0keDr 7 жыл бұрын

You can use double sided PC board and solder them to the can in place of the lids or as the other chap indicated save the cut out and solder it back.

@lylewatts6370 6 жыл бұрын

Another great video Buddy, We have a problem with our 440 duplexer with the new DR-2X repeater. A couple attempts at tuning with crude tools has made it a little better. But it's a project that is not top priority as we have 4 repeaters and none have much usage.

@TheRadioShop 6 жыл бұрын

Thanks Lyle. I have done it with a handheld before but it is a bit touchy. Thanks for watching.

@earlyadapter643 9 ай бұрын

I like the appropriate cans and actually it should read "Maxwell inside"

@g1fsh 8 жыл бұрын

Wow Buddy that is a great video full of useful information and it was very well presented. Really looking forward to more repeater building videos. Thanks mate

@TheRadioShop 8 жыл бұрын

+Gary g1fsh Thanks Gary. I will say this video was very fun to do. Tried to squeeze in as much information as I could but was getting way to long. Will cover more in the next segment. Glad you liked it my friend.

@pierrelataillade7564 7 жыл бұрын

Excellent video buddy...... Thank you.

@TheRadioShop 7 жыл бұрын

Thank you

@ryan_niemi 5 ай бұрын

The filter isolation and insertion loss would be much better if the resonator rod were the right diameter. The resonator outside diameter should be 3.6x smaller than the inside diameter of the cavity for a 50 ohm impedance. A cavity filter is, effectively, a 1/4 wave coax stub with one end shorted and the other end open-circuit. If the resonator is not the right diameter in relation to the cavity to match the system's impedance, insertion loss increases and isolation worsens and the cavity filter performs poorly. Also, about paint cans being too long, it doesn't matter if the cavity is longer than necessary. The cavity can be any length as long as it isn't so short it touches the end of the resonator rod. Only the length of the resonator rod (and to a much smaller degree, capacitance from the cavity to the resonator rod) matters.

@597388 Жыл бұрын

on a humorous note if you use a de caffinaited coffee can, will the signals be attenuated ? lol. btw great video thank you

@joekirklin Жыл бұрын

I started watching thinking these are pass-band cavities, but finished thinking they must be notch filters. Can you explain?

@TheRadioShop Жыл бұрын

You are actually correct on both. A repeter systems use different frequencies for transmit and receive, the duplzer allows you to use on antenna. Each radio will have a pass and notch filter then it couples to one antenna for both transmit and recieve.

@KK4CNM 6 ай бұрын

I'm in need of a duplexer for the 33cm band. They are few and far between and expensive! Any advice on building a DIY version?

@TheRadioShop 6 ай бұрын

Building a efficient duplexer for 900 mhz would be next to impossible, They are so sensitive, However there are a lot of 800 mhz stuff on the market. I have several 800 mhz duplexers. I will experiment on one soon as I get a chance. Click on show more tab and shoot me an email, I will let you know.

@mackwood2164 7 жыл бұрын

Thank you for this knowledge.

@TheRadioShop 7 жыл бұрын

Thank you for watching.

@IamDerick 7 жыл бұрын

Pretty cool project. I really enjoy this one. :)

@TheRadioShop 7 жыл бұрын

Very simple to do. All it takes is a little will. Thanks

@PelDaddy 7 жыл бұрын

I thought the brass pieces were shell casings to begin with! Thanks for sharing.

@TheRadioShop 7 жыл бұрын

lol, someone else thought that. Now if you can find some large shell casing, makes for nice cavities.

@user-un1wq5cc4w 5 жыл бұрын

👍👍👍👍👍👍👍👍

@jaybats7865 4 жыл бұрын

So to adjust the transmit frequency you slide the rod and to adjust the receive frequency you turn the nut. Is that correct?

@someguyinsantaclara 4 жыл бұрын

You mentioned stability and silver coating. Are there any other materials you would recommend that would be slightly more stable?

@TheRadioShop 4 жыл бұрын

Only thing better would be gold.....

@MrCorynick 5 жыл бұрын

I'm hoping to apply the same theory to a 900mhz filter using maybe quart or pint paint cans. Wish me luck

@k7ilo_Las_Vegas 10 ай бұрын

Years later but question. What is the best way to solder the brass to the aluminum. You did not show what your process was... Thanks

@kiloinvegas 3 ай бұрын

Anybody????

@kinggreene 2 жыл бұрын

you can use the swivel type pipe cutter to swage the brass pipe down to size just go slow

@AECRADIO1 5 жыл бұрын

Tubing pieces should be matched better for a tighter joint, otherwise the tuning can change easily by simply touching them.

@TheRadioShop 5 жыл бұрын

That is correct. Hard to find tubing here. The way you do this one is when you get it tuned you are to solder the tubing on the inside.

@kg4hlz 7 жыл бұрын

Relay good video! 73s.

@TheRadioShop 7 жыл бұрын

Thank you very much

@Etherionix 7 жыл бұрын

Excellent.

@TheRadioShop 7 жыл бұрын

Thanks Don

@BitsBlitzPH 7 жыл бұрын

Could you please for the sake of two meter fans make a vid of the 2 meter duplexer. Great video and Thank you very much

@TheRadioShop 7 жыл бұрын

I would really like to do that. However, I do not have a 2 meter duplexer or the materials needed to build one. Would be fun to do one.

@BitsBlitzPH 7 жыл бұрын

:( i really wanna build one but couldn't find any steps as clearly as what you have showed here. having a hard time to follow your source's instructions.

@chrisdowland 6 жыл бұрын

rex pogi larger can longer rods

@FaZeWIDOW 2 жыл бұрын

thats funny the only radioshack near me is also thomson tv

@TheRadioShop 2 жыл бұрын

The one I know of is in Washington NC. You near by?

@rakotondramananasamuel3970 5 жыл бұрын

is it possible to create lte band with cavity duplexer like this

@TheRadioShop 5 жыл бұрын

I do not think it would work that good at high frequency.

@jonka1 4 жыл бұрын

Not knowing anything about these devices I wonder if the use of foil and a plastic end cap might be physically non-rigid enough to allow for slight de-tuning with time and temperature.

@DoRC 7 жыл бұрын

a 1/2 gallon paint can is just under 6" tall so that might be an option.

@TheRadioShop 7 жыл бұрын

That would work

@arduinou5944 5 жыл бұрын

It seems you abandoned this project, it was very interesting

@TheRadioShop 5 жыл бұрын

Not really, was waiting to pick up a used repeater at a decent price.

@phantomsurvivor6169 7 ай бұрын

Better than a cheap $100 Chinese flatpack duplexer?

@dennispeake1877 8 жыл бұрын

g'day mate don't know what the name is but what a excellent job. Thanks for sharing your project. 73 de Dennis vk4oc.

@TheRadioShop 8 жыл бұрын

+Dennis Peake Thanks Dennis. Name is Buddy. Glad you found the video entertaining. So much detail was left out though but to keep the video short had to edit out an hour.

@mikesradiorepair 8 жыл бұрын

Looking good Buddy. Still need another can? Sounds like somebody needs to get busy drinking some coffee. :) Wish I had known last week you would be needing the BNC T. Could have dropped a handfull in the mail for you. If you do get a SA with tracking generator you'll wonder how you ever lived without one. I opted for the option and love it. Great for things like this, tuning low pass filters and checking crystal and ceramic filters. Mike

@TheRadioShop 8 жыл бұрын

+MikesRadioRepair Yeah, drinking a pot full this morning. Keeps me going lol. Getting ready to cancel the order I made on the tee's. They are out of stock so have to search elsewhere. As far as SA I really like to get the Rigol DSA815-TG, but 1400 bucks will be a while. Also like the get a Rigol DSG815 signal generator so I would have more modern equipment. Well maybe one day. Would be a nice addition to the shop. Guess I can search a used piece but even that is sort of high. Surly not making a killing here in the shop lol. Thanks for the comment Mike, always look forward to them.

@mikesradiorepair 8 жыл бұрын

+The Radio Shop How many T's do you need? I have a bunch of them. They are the good silver plated ones. Not the cheap junk ones from China. Mike

@TheRadioShop 8 жыл бұрын

+MikesRadioRepair Hi Mike. I am in need of 5. They all need to be of the same type/make so they do not cause problems at UHF.

@mikesradiorepair 8 жыл бұрын

+The Radio Shop Hmm, don't have 5 exactly the same in silver plated. Do have exact match in normal plated versions made by MXT if that works for you.

@TheRadioShop 8 жыл бұрын

+MikesRadioRepair Cool, anything works. can be 2 of one kind, 2 of another kind, then a single. Other words the 2 on receiver side needs to match, the 2 of transmit side need to match, then the antenna tee can be either. This way there is no impedance bump.

@kb5zcs 7 жыл бұрын

Would these duplexers work for a D-star UHF repeater,BTW great video.......

@TheRadioShop 7 жыл бұрын

No reason why they should not.

@Augustheatsucks 8 жыл бұрын

AFR 1200, classic ;)

@TheRadioShop 8 жыл бұрын

Agreed!

@LavaKimo 4 жыл бұрын

Your link to N4GUS doesn't work. The "p" in pages needs to be a capital "P" and then it will work.

@vk2amv 7 жыл бұрын

Can you tell me the diameter and length of your cans? We don't have coffee sold in cans like there here in Australia, but I should be able to find something similar if I know what size can I am looking for. Thanks

@TheRadioShop 7 жыл бұрын

No problem. These are 30.6 ounce cans (0.000904.95 ml). They are 5 7/8 inches tall (150 mm). And 6 inches in diameter (155 mm) Hope that helps.

@vk2amv 7 жыл бұрын

That helps very much. I think I can use a large beetroot can to do the job. Thank you

@Dazzwidd 5 жыл бұрын

the Nescafe 500G tins are the same dimensions I think. Fairly easy to get, many workplaces have them in the lunch room for staff to get their caffeine fix. If you drink it, wait until it's on special and buy some when they're $16 each. Then either donate the coffee to a good cause or wait until you finish drinking it all if you're patient enough. You could talk to some tradieswho restore wood floors and ask them for empty stain and varnish cans also :)

@nutlock2857 8 жыл бұрын

Hi Buddy -thank you for another great video! Can I ask you, did you manage to find any new info about the CB Sig- gen ? I have looked myself with no joy 73 from the UK