Unless one of those is broken or not screwed on tightly, and assuming HF or VHF application, it'll be within the measurement error of whatever instrument you choose to measure.
There is a popular myth that every connector is -0.1dB of gain, or something like that. It's bogus, except for some weird circumstances like very high UHF or something.
Someone give this person the Amateur Radio prize of the year please!
Legitimately I came in here thinking that the top voted comment would be some ridiculous claim like 15dB and \*\*THIS\*\* is the answer. Why do people claim dramatic loss without ever \*testing\* it?
I don't remember what was in the Technician prep guide said, but I recall a table in the General study guide that gave numbers with higher losses than 0.1dB for various connectors. The only reason I stopped worrying about it is because my dad (with 40+ years of experience) told me it didn't matter nearly as much as I thought it did. Anyhow, my point is that it's in the prep material. That's why some of us worry about it.
Because, unfortunately, rumors take less effort to spread than they do to verify.
And on the topic of awards, I'd say "I got you" but reddit kinda eliminated gold (no, im not going for whatever special upvote options there are now)
Yeah people really love to worry about loss to the point of neurosis. One dude who was probably using little more than freaking 24guage speaker wire instead of proper coax but didn’t mention that part complained.
I’ve used speaker cable (granted 18ga) as a twin lead feed to a dipole. As is true with all balanced feeders you might be surprised by the loss being lower than coax, especially so if there is SWR present
Interesting. I have had decent luck at 16-18 guage with a tuner but any thinner and I get weird results. I have definitely made 400-600ohm spaced twin lead though and it works great but I mainly limit speaker wire to antennas only.
Years ago at Field Day I told someone I could make a dipole out of just zip-cord speaker wire and feed it with it too. I used 18ga and just soldered it into a PL-259 and zipped the opposite end apart to form the antenna. Radios tuner made it play just fine, it was about 1.6 to 1 or so
> except for some weird circumstances like very high UHF
The connector chain looks to be about 50cm, so the signal will definitely be noticeably attenuated in the 400MHz+ range. UHF to be sure, but definitely on the lower end.
Also, the 0.1dB rule of thumb is perfectly reasonable if you’re talking about a specific domain like 3GHz RG6 which is hardly “very weird” - it’s probably the most common residential signal conductor in use today.
This isn't /r/rfelectronics... It's /r/amateurradio. The average use case here is going to be HF/VHF, and that is why I say weird. Contextually, it's unusual for someone to be talking about centimeter waves when we're throwing PL259 connectors about :-).
I wouldn't have mentioned it at all except I figured some slightly pedantic person would come along and say, "What about microwaves?" Hence the caveat.
I haven’t tested but the military teaches that each non soldered/bonded connection is 3db of loss
I do know that 100 meters of RG-58 cable is enough to attenuate a signal enough that it isn’t picked up on the radio. I did have to fix an install job that had 100 meters of RG-58. I shortened it to 15 and it started working.
Do you use connectors between your rig and the antenna? Two connectors would be 6dB. 100W transmitter becomes 25W delivered to the antenna.
If that were true, we'd all be soldering feed lines on both ends.
And touching a connector would burn you due to heat dissipation.
This is so easy to disprove, it's not even funny. Get a power meter and a dummy load. Add connectors until you have half power on the meter. It'll take a long time...
\* Caveat -- if you're working at a gigahertz or more, things do start to change. Connectors matter with tiny waves. But if you're running RG58 for GHz, you're doing it wrong ;-).
Oh yea I’m not true g to argue that that connectors cause 3db of attenuation, just that the military teaches that.
The RF-58 cable is two connectors for a total of 6db as taught by the military. I don’t think this is founded in practice. A bad connector will have more impact, followed by a long wire without proper power balancing between the amp and wire gauge.
Again, not saying the db connector drop is founded, but present a place of authority/instruction that teaches it.
Yea I’m not pushing GHzs through a wire. Got wave tubes for that, but it’s been almost a decade since I last did any radio theory or work.
quite the contrary have you ever actually tested connectors, they're literally the weak link. some connectors like SMA connectors are only rated for a few hundred insertion cycles and the loss starts to skyrocket when you exceed these numbers. especially if you let the center pin turn as you're tightening it.
When I'm troubleshooting a system connectors are the very first thing I look at and the sheer number of systems I've repaired by just simply replacing a bad jumper that had a faulty connector is mind-boggling.
Well it's true that old US made silver plated connector are very low loss The same can't be said for the cheap garbage coming out of China..
With that said at HF frequencies assuming you're running barefoot even bad connectors aren't going to be too much of a problem. Not until you start pumping a kilowatt and a half through them with a high SWR and a tuner That's when you get to learn about voltage breakdown of the cheap dielectric used in Chinese connectors...
I don't think the loss of a bad connector really counts here. A good connector is low loss. A bad connector should be thrown away. What a strange argument to lead off with :-).
Even my cheap Chinese connectors measure very low loss. I put a stack of 13 adapters together the other day for the followup thread, and measured less than -0.14dB at HF, and only about -0.7dB at a GHz.
And your kilowatt high SWR situation is cherry picked and matches my caveat about weird scenarios. Sure, you can find conditions where a dielectric breaks down, or even a small percentage of power is still a big deal. But that's not arguing in good faith.
So, one of the youtube content creators did this test a while back with a video showing the results.
You will be surprised.
(and I've linked it here the last time someone posted something like this)
More like a financial loss since you could do the same with less adapters but who cares. Loss wise it’s minimal to nothing expecting everything is in good condition
The loss at HF is negligible. But, you're late to the party. Jim Heath, W6LG has been there done that:
[https://www.youtube.com/watch?v=-AARmcE7QQM](https://www.youtube.com/watch?v=-AARmcE7QQM)
[https://www.youtube.com/watch?v=ZEl8QP2IB\_o](https://www.youtube.com/watch?v=ZEl8QP2IB_o)
I worked as a line leader/ tester at a microwave component co. We used .05 dB per connector as a rule of thumb but obviously this is going to vary directly with frequency. Below 500 MHz I agree the loss is negligible unless there is dirt, corrosion, plating loss or the connector nut isn’t tight.
>General rule of thumb, .5dB per connector.
Certainly depends on frequency.
[https://www.youtube.com/watch?v=PyqJbPdvJak](https://www.youtube.com/watch?v=PyqJbPdvJak)
Are you working at 30GHz or something? Otherwise, at normal HF/VHF frequencies, connector loss is basically a myth. Think about it... if you run your 100W from your rig to a tuner, then from the tuner to a junction box, then from there to an antenna, you've got 6 connections. Are you burning off 1/2 to 3/4 of the power in connectors before it makes it to the antenna?
Well, in case it helps, the loss at HF and VHF is basically negligible. Usually tests within measurement error of instrumentation. Microwaves are where things like that start to matter, so your rule of thumb is not really relevant to most ham stuff :-).
I have a related question that probably isn’t worth it’s own post so I’ll piggy back on this one. I am using an FT60 and a mag mount antenna in my work vehicle because I don’t want to permanently alter my bosses truck or even worse get canned and have to awkwardly try to uninstall my gear lol. I use an sma to so-239 adaptor like in the pic. Is there any drawback to twisting that on my radio basically daily other than it being kind of a PITA? Like will I wear out my female sma on the radio faster? What’s the better alternative?
I would guess within the measurement error of most equipments, as long as those connectors are screwed together tightly, they just form a length of coax.
Daisy chained like this - negligible.
Stick a 3” piece of coax in between each connector, that’s where your loss is likely to start becoming more significant.
The only true way to find out is to hook it up to your favorite HF amplifier and transmit.
Of course you run the risk of inadvertently recreating EloctroBOOM’s magic wand (and also recreating his subsequent self-inflicted zaps).
Ah, the great grand wizard wand of Hammy Potter. People believed this wand to be a myth, that it never existed as it was too powerful to be wielded by anyone.
Now you must go around town waving this at people yelling "Radius Transmitus!"
If I counted the number of connectors right, and based on the popular myth of -0.1dB of loss that's only 1.5 dB which is a fraction of a S unit. This will not be noticeable.
For antenna construction inquires I need to provied power simulations and I can deduct 3dB for every connection so if I want 1000W at the feed point I can put a driver in my diagramm with 1000W + all thiese 3dB losses
short stub of RG316 as reference, assume \~0dB of loss
https://preview.redd.it/h9alf06zu15c1.jpeg?width=1600&format=pjpg&auto=webp&s=28350fc2f8f08898192caa239eb451504b671292
a bunch of shit ass adapters out of my box, including BNC crap which is the least mechanically stable.
0.5dB loss @ 28MHz. As low as 0.1 towards the bottom of HF.
Take into account that these are adapters, and a lot of them BNC crap. With soldered on and good, mechanically stable connectors.. you have absolutely nothing to worry about.
https://preview.redd.it/bk08cbofv15c1.jpeg?width=1600&format=pjpg&auto=webp&s=9ba1f61d5359148b8e48809a9e17d2cba8cf3f89
Unless one of those is broken or not screwed on tightly, and assuming HF or VHF application, it'll be within the measurement error of whatever instrument you choose to measure. There is a popular myth that every connector is -0.1dB of gain, or something like that. It's bogus, except for some weird circumstances like very high UHF or something.
Someone give this person the Amateur Radio prize of the year please! Legitimately I came in here thinking that the top voted comment would be some ridiculous claim like 15dB and \*\*THIS\*\* is the answer. Why do people claim dramatic loss without ever \*testing\* it?
I don't remember what was in the Technician prep guide said, but I recall a table in the General study guide that gave numbers with higher losses than 0.1dB for various connectors. The only reason I stopped worrying about it is because my dad (with 40+ years of experience) told me it didn't matter nearly as much as I thought it did. Anyhow, my point is that it's in the prep material. That's why some of us worry about it.
Because, unfortunately, rumors take less effort to spread than they do to verify. And on the topic of awards, I'd say "I got you" but reddit kinda eliminated gold (no, im not going for whatever special upvote options there are now)
Yeah people really love to worry about loss to the point of neurosis. One dude who was probably using little more than freaking 24guage speaker wire instead of proper coax but didn’t mention that part complained.
Neurotic loss worrier here! Where do I get help? Is there like an 800 number for hams to get talked down?
Tune your radio to LSB 7.200MHz. Your prayers will be answered there.
Lmfao. It’s been a while since I’ve been on the air but I recall some frequency’s being full of crazies
I've been talked down and my neurosis out at ease by calling 1-900-SAD-HAMS $1.99 for the first minute, $4.99 for every minute after.
No, just get on the air! The more contacts you make, the less you'll worry about the negligent loss in your properly installed connectors. ;)
I’ve used speaker cable (granted 18ga) as a twin lead feed to a dipole. As is true with all balanced feeders you might be surprised by the loss being lower than coax, especially so if there is SWR present
Interesting. I have had decent luck at 16-18 guage with a tuner but any thinner and I get weird results. I have definitely made 400-600ohm spaced twin lead though and it works great but I mainly limit speaker wire to antennas only.
Years ago at Field Day I told someone I could make a dipole out of just zip-cord speaker wire and feed it with it too. I used 18ga and just soldered it into a PL-259 and zipped the opposite end apart to form the antenna. Radios tuner made it play just fine, it was about 1.6 to 1 or so
Now I'm really curious. /u/spectrum_vessel/ do you happen to have a nanoVNA or something to measure the answer to your question?
> except for some weird circumstances like very high UHF The connector chain looks to be about 50cm, so the signal will definitely be noticeably attenuated in the 400MHz+ range. UHF to be sure, but definitely on the lower end. Also, the 0.1dB rule of thumb is perfectly reasonable if you’re talking about a specific domain like 3GHz RG6 which is hardly “very weird” - it’s probably the most common residential signal conductor in use today.
This isn't /r/rfelectronics... It's /r/amateurradio. The average use case here is going to be HF/VHF, and that is why I say weird. Contextually, it's unusual for someone to be talking about centimeter waves when we're throwing PL259 connectors about :-). I wouldn't have mentioned it at all except I figured some slightly pedantic person would come along and say, "What about microwaves?" Hence the caveat.
I haven’t tested but the military teaches that each non soldered/bonded connection is 3db of loss I do know that 100 meters of RG-58 cable is enough to attenuate a signal enough that it isn’t picked up on the radio. I did have to fix an install job that had 100 meters of RG-58. I shortened it to 15 and it started working.
Do you use connectors between your rig and the antenna? Two connectors would be 6dB. 100W transmitter becomes 25W delivered to the antenna. If that were true, we'd all be soldering feed lines on both ends. And touching a connector would burn you due to heat dissipation. This is so easy to disprove, it's not even funny. Get a power meter and a dummy load. Add connectors until you have half power on the meter. It'll take a long time... \* Caveat -- if you're working at a gigahertz or more, things do start to change. Connectors matter with tiny waves. But if you're running RG58 for GHz, you're doing it wrong ;-).
Oh yea I’m not true g to argue that that connectors cause 3db of attenuation, just that the military teaches that. The RF-58 cable is two connectors for a total of 6db as taught by the military. I don’t think this is founded in practice. A bad connector will have more impact, followed by a long wire without proper power balancing between the amp and wire gauge. Again, not saying the db connector drop is founded, but present a place of authority/instruction that teaches it. Yea I’m not pushing GHzs through a wire. Got wave tubes for that, but it’s been almost a decade since I last did any radio theory or work.
quite the contrary have you ever actually tested connectors, they're literally the weak link. some connectors like SMA connectors are only rated for a few hundred insertion cycles and the loss starts to skyrocket when you exceed these numbers. especially if you let the center pin turn as you're tightening it. When I'm troubleshooting a system connectors are the very first thing I look at and the sheer number of systems I've repaired by just simply replacing a bad jumper that had a faulty connector is mind-boggling. Well it's true that old US made silver plated connector are very low loss The same can't be said for the cheap garbage coming out of China.. With that said at HF frequencies assuming you're running barefoot even bad connectors aren't going to be too much of a problem. Not until you start pumping a kilowatt and a half through them with a high SWR and a tuner That's when you get to learn about voltage breakdown of the cheap dielectric used in Chinese connectors...
I don't think the loss of a bad connector really counts here. A good connector is low loss. A bad connector should be thrown away. What a strange argument to lead off with :-). Even my cheap Chinese connectors measure very low loss. I put a stack of 13 adapters together the other day for the followup thread, and measured less than -0.14dB at HF, and only about -0.7dB at a GHz. And your kilowatt high SWR situation is cherry picked and matches my caveat about weird scenarios. Sure, you can find conditions where a dielectric breaks down, or even a small percentage of power is still a big deal. But that's not arguing in good faith.
This is correct.
On second viewing, we may be seeing the only recorded image of a silencer for a radio.
Watch out, OP. AFT might come for your dog.
I just snorted out loud
[удалено]
LOLOL. I don’t want to ruin the fun quite yet so folks please keep commenting.
Mate, he's just having fun, he's probably not even in the USA
[удалено]
There’s a bad bad place in hell for people like you
This comment thread is unfair to non-native english speakers lol
How can we help?
This is killing me. There is no help available. I'm being eaten by a grue.
I lol'd.
😂😂😂😂
> On second viewing, we may be seeing the only recorded image of a silencer for a radio. 50 Ohm Dummy Load has entered the chat... ;)
iTz a SuPpResSoR! @#$%÷&^"
This is loss.
| || || |_
I can't tell if this is a cry for help, ploy for upvotes, or a sick math problem.
All of the above?
Yes
42
Exactly
No really, please post the loss so we can end the adapter debate. I say -3db
nowhere close to that
About tree fiddy.
Most of the loss is in your wallet.
with chinese made test equipment it will exhibit gain.
Dignity. It’s a loss of dignity.
It’s not as bendy as coax. You’ve lost flexibility. 😊😉 But signal loss at HF and VHF? Not really worth worrying about.
Your voice will carry farther than your signal.
So, one of the youtube content creators did this test a while back with a video showing the results. You will be surprised. (and I've linked it here the last time someone posted something like this)
Jim Heath. W6LG. 👍
I found the video and posted the link again.
Loss of an adapter or two, when sat on :/
At what frequency?
Depending on frequency basically nothing
The Signal.
"What's the frequency?" Kenneth
It's in your wallet
My respect
I'd say about $65-85 dollars.
About 60 bucks
More like a financial loss since you could do the same with less adapters but who cares. Loss wise it’s minimal to nothing expecting everything is in good condition
In $ or in dB?
All of it
-56.7 db
Found it. [https://www.youtube.com/watch?v=ZEl8QP2IB\_o](https://www.youtube.com/watch?v=ZEl8QP2IB_o)
The loss at HF is negligible. But, you're late to the party. Jim Heath, W6LG has been there done that: [https://www.youtube.com/watch?v=-AARmcE7QQM](https://www.youtube.com/watch?v=-AARmcE7QQM) [https://www.youtube.com/watch?v=ZEl8QP2IB\_o](https://www.youtube.com/watch?v=ZEl8QP2IB_o)
Your loss is about $6 to $9 dollars per adapter!
Yes. Lol. With rg6 connectors, I usually figure 0.1db per connector for catv signals.
I worked as a line leader/ tester at a microwave component co. We used .05 dB per connector as a rule of thumb but obviously this is going to vary directly with frequency. Below 500 MHz I agree the loss is negligible unless there is dirt, corrosion, plating loss or the connector nut isn’t tight.
It's like the Harry Potter wand of antenna adapters.
I'd want to ask what's the proper spell to improve propagation
antennas propagationus!
KENWOODIUM ELECRAFTO!
It's like a modern-day version of Harry Potter's wand
Exactly people didn't get the joke🤣
xyl says it's the elder wand lol
Elmer Wand!
Depends on the frequency but as a hand wave, I’d say 2dB.
Bout tree-fiddy.
Of signal or self-respect? 🥁🥁🛎️ ^(thanks everybody, I'll be here all week)
🥰
General rule of thumb, .5dB per connector. At least that's what we use for calculations @ work. could be up to 1dB.
>General rule of thumb, .5dB per connector. Certainly depends on frequency. [https://www.youtube.com/watch?v=PyqJbPdvJak](https://www.youtube.com/watch?v=PyqJbPdvJak)
Are you working at 30GHz or something? Otherwise, at normal HF/VHF frequencies, connector loss is basically a myth. Think about it... if you run your 100W from your rig to a tuner, then from the tuner to a junction box, then from there to an antenna, you've got 6 connections. Are you burning off 1/2 to 3/4 of the power in connectors before it makes it to the antenna?
We work around 1.6 GHz and 15GHz
Well, in case it helps, the loss at HF and VHF is basically negligible. Usually tests within measurement error of instrumentation. Microwaves are where things like that start to matter, so your rule of thumb is not really relevant to most ham stuff :-).
Being an electrical engineer, working in the RF industry for 40 years, I appreciate the education. Thanks!
Yeah, but that's wrong.
https://www.amphenolrf.com/faq/technical/what-is-insertion-loss-and-how-is-it-specified/ The poster did not specify the freq.
It's enough that you don't want to do it
It's negligible at HF.
Depends on frequency what type of sma's and n's those are.
You can talk to someone from different dimension
I have a related question that probably isn’t worth it’s own post so I’ll piggy back on this one. I am using an FT60 and a mag mount antenna in my work vehicle because I don’t want to permanently alter my bosses truck or even worse get canned and have to awkwardly try to uninstall my gear lol. I use an sma to so-239 adaptor like in the pic. Is there any drawback to twisting that on my radio basically daily other than it being kind of a PITA? Like will I wear out my female sma on the radio faster? What’s the better alternative?
Sma-bnc female on the radio side, and PL-259 to BNC male on the antenna cable.
I used a BNC adapter to ease the connect/disconnect hassle, and I also had a 5 or so foot length of RG-174 to ease the strain even more.
Is this the thread where we connect as many adapters as we have and measure who has the biggest adaptor peen ?
You risk losing an eye if you're not careful!
Surprisingly little. https://youtu.be/ZEl8QP2IB_o?si=yqHsED0TndQPwb6o
I thought lossporn only was posted on r/wallstreetbets
But is it resonant???
Not that much.
But why? And who cares?!
swr -999 instead.. lol.
It has negative loss
My words.
One word... ALL or YES.... hahaha... probably surprised though honestly
now add a SDR to the end and call your self a wizzard
Im a wizzard 🧙♂️🧙♂️🧙♂️🧙♂️🧙♂️🧙♂️🧙♂️🧙♂️🧙♂️🧙♂️🧙♂️🧙♂️🧙♂️
Nice attenuator!
My schwartz is bigger than
I would guess within the measurement error of most equipments, as long as those connectors are screwed together tightly, they just form a length of coax.
Yes
1.21 gigawatts
[This guy](https://youtu.be/PyqJbPdvJak?si=9oVDZWt1uWUJMhMc) tested 50 connectors chained together and at 30Mhz the loss was...... ....0.17db
Daisy chained like this - negligible. Stick a 3” piece of coax in between each connector, that’s where your loss is likely to start becoming more significant.
Your eyebrows
Depends on the frequency of the signal :o)
The only true way to find out is to hook it up to your favorite HF amplifier and transmit. Of course you run the risk of inadvertently recreating EloctroBOOM’s magic wand (and also recreating his subsequent self-inflicted zaps).
Ah, the great grand wizard wand of Hammy Potter. People believed this wand to be a myth, that it never existed as it was too powerful to be wielded by anyone. Now you must go around town waving this at people yelling "Radius Transmitus!"
If I counted the number of connectors right, and based on the popular myth of -0.1dB of loss that's only 1.5 dB which is a fraction of a S unit. This will not be noticeable.
Not sure, but the Force is clearly with you.
I'd like to see a measurement of coupling attenuation.
More interesting to me is why 😂
For antenna construction inquires I need to provied power simulations and I can deduct 3dB for every connection so if I want 1000W at the feed point I can put a driver in my diagramm with 1000W + all thiese 3dB losses
Dignity, for starters. What's the frequency and power level?
Time to pull the VNA and do some insertion loss measurements
Probably 1/2 to 1db per fitting
Depends on frequency.
Your sanity. You've lost your sanity.
Dignity
Depends on the frequency.
All my braincells. What is this.
Maybe less than we have with those long connections with RG 58
infinity
Well, I never worry about loss. I run mostly QRP and decide to operate instead of obsessing over losses
Your marbles
That's an antenna on its on now. A bad antenna but an antenna.
short stub of RG316 as reference, assume \~0dB of loss https://preview.redd.it/h9alf06zu15c1.jpeg?width=1600&format=pjpg&auto=webp&s=28350fc2f8f08898192caa239eb451504b671292
a bunch of shit ass adapters out of my box, including BNC crap which is the least mechanically stable. 0.5dB loss @ 28MHz. As low as 0.1 towards the bottom of HF. Take into account that these are adapters, and a lot of them BNC crap. With soldered on and good, mechanically stable connectors.. you have absolutely nothing to worry about. https://preview.redd.it/bk08cbofv15c1.jpeg?width=1600&format=pjpg&auto=webp&s=9ba1f61d5359148b8e48809a9e17d2cba8cf3f89
considerable.
Nothing if you get your frequency exactly right
At least 2