Hook up swr/watt meter inline with amp

[friskidog]

I'm confused, this video https://www.youtube.com/watch?v=8UdL0UvULrA seems wrong or maybe I am.
He says 1st jumper goes from radio to input side of amp, then go from input side of meter to antenna side of amp. I read somewhere else to go from radio to antenna side of amp, input side of amp to input side of meter and last antenna side of meter to antenna.
Who's right?
BTW my jumpers are 18" does it matter?

 

[gewecke]

Radio + meter + antenna. Ditch the illegal amp. 73, n9zas

 

[friskidog]

That's no help but thanks for trying!

 

[gewecke]

Simple and legal is always better. 73, n9zas

 

[friskidog]

Why do you hams come in here and tell us what's legal and not? I've seen lots of your sarcastic replies, did you get kicked out of the ham forum? Yes I had a license for 10 years and anal ham operators are why I let it expire. 73's!

 

[SCPD]

Radio to amp radio input, ANT out of amp to Radio port of VSWR/WATT meter, Antenna port of VWSR/WATT meter to Antenna. You want to place the VSWR meter last in line. Also when tuning an antenna leave all amps out of the circuit. Use an antenna analyzer for best tuning of antenna, and then add amp and external VSWR/watt meter. Make sure you have good connectors, coax and antenna setup before you add an amp. Get your antenna setup as best as possible before you do anything. That is JMHO. I know I am new here, but I am at least giving you some honest answers. Also read up on bonding of vehicle body parts and such. Helps a bunch if you are serious about getting the best performance out of your entire system. Again, JMHO. Hope this helps and have a good day.

 

[friskidog]

Thanks that's what I needed to know!

 

[AC9BX]

...1st jumper goes from radio to input side of amp, then go from input side of meter to antenna side of amp. I read somewhere else to go from radio to antenna side of amp, input side of amp to input side of meter and last antenna side of meter to antenna.

It depends on what you're trying to measure. The meter goes in between whatever it is. Connect the stuff without a meter, then insert the meter. If you're measuring power or SWR from the radio before an amplifier then the meter goes in between. If you want to measure the amplifier output then the meter goes last. The meter needs to be rated for use at the amplifier power level.

my jumpers are 18"

The longer the jumper the more loss it has, like all of your cable.

Why do you hams come in here

For me it's the comedy value and to try to be helpful.

I had a license for 10 years

A former licensed amateur knows all this.

 

[KC4RAF]

Agree with all the other posters.

Shorter is by all means better, (we're not talkin' about manhood here ya know! lol)
Keep everything SHORT if at all possible, and double check all connectors. A bad solder is sometimes hard to locate.
I also come onto the cb forum for the entertainment value. There are many valid questions asked here, but own up to it, some just brings a smile to your face or a face palm action. lol Some of the 11 meter crowd eventually become hams.

 

[SCPD]

And yes it does depend on what you are trying to measure, or where you are trying to measure power. Most place meters at the end of the line, after the amp as to see the total output. Like said. Use quality coax, connectors, a good mount and antenna, and tune antenna without the amp in line. Coax jumpers should be made to reach from point a to b. Add a bit for future service if needed. 3ft coax jumpers usually work rather well as far as length go. Pre made ones anyway. And stay away from the truck stop coax and connectors and such. But quality. Breedlove mount, or similar, belden, Andrew, Commscope, Eupen, Shireen, Times Microwave, these are just a few good known manufactures of good coax. Amphenol connectors work well, and also make sure to have a decent VSWR/power meter. Again, keep away from the truck stop stuff. JMHO.
And take your time installing the amp. Keep all power and grounds as short as possible and take grounds directly to frame or frame bolt. And lastly, don't forget to use no-ox on all connections like power and ground. Don't use on connectors though.
Good luck and be safe.

 

[BBB007]

Why do you hams come in here and tell us what's legal and not? I've seen lots of your sarcastic replies, did you get kicked out of the ham forum? Yes I had a license for 10 years and anal ham operators are why I let it expire. 73's!

Because of the nature of Trolling... Definition: "make a deliberately offensive or provocative online posting with the aim of upsetting someone or eliciting an angry response from them."


Yes, has been "temporarily banned" in the past.

 

[Retroradio]

Anyone stop to think it was mentioned because it's the law....Just saying.
The comment in itself isn't really offensive and simply stated a fact. I agree Simple is better when it comes to hooking up a radio.
I had the misfortune of listening to channel 6 bleed across 3 bands on AM clear as day last week. I can't be sure but do you think they where running with an amp.......
73s

 

[dmack550]

Why do you hams come in here and tell us what's legal and not? I've seen lots of your sarcastic replies, did you get kicked out of the ham forum? Yes I had a license for 10 years and anal ham operators are why I let it expire. 73's!

Yeah those hams love to look down from Mt. Olympus on us lowly redneck cb hicks and a warm feeling of superiority engulfs them. Us hillbillies don't know a diode from a bottle of hooch and we just can't be expected to behave in a civilized "ham" society. Shame on us for not looking up at you there on the Mount and wishing we could be as good and proper as you "hams" are. Sorry but us lowly cb'ers just don't WANT to be you. Sorry.

 

[BBB007]

Amateur Radio...still boring most of the time.

CB Radio...still relaxed, yet exciting and fun at times

I learned a few weeks ago that I must run an SWR meter in between my MOSFET powered RCI 2970N2 and the amp. That particular radio, and others like it, are just too easily damaged if VSWR is not below 1.5 :roll:

 

[friskidog]

Yeah those hams love to look down from Mt. Olympus on us lowly redneck cb hicks and a warm feeling of superiority engulfs them. Us hillbillies don't know a diode from a bottle of hooch and we just can't be expected to behave in a civilized "ham" society. Shame on us for not looking up at you there on the Mount and wishing we could be as good and proper as you "hams" are. Sorry but us lowly cb'ers just don't WANT to be you. Sorry.

You should write poetry, well said LOL!

 

[SCPD]

Yep. Mosfets don't like a bad VSWR. From my experience with radios using them. Anything over a 1.3:1 things start acting funny and a lot more heat is created. They are more prone to blow as well. This is CB and export radios we are speaking of, let's get this clear. Most if not all HF radios use MOSFET finals, difference is they are truly made for RF. The ones being used in most CB and export radios are not. They can be used obviously but aren't exclusively made for RF.
Having an external VSWR meter isn't a bad thing at all and should be used with any radio that doesn't have a good one built in. Again, most HF radios have pretty good VSWR protection as well and will fold back power or just plain not TX if the VSWR is bad. Your 2970N2 won't do that! Just make sure that you use a good meter and keep the VSWR below 1.3:1 if possible. Also keeping the golden screwdrivers out of them help a bunch. Most just need a tune and alignment. No need to hot rod this radio for a few extra watts that no one on the receiving end will notice. It may make your watt meter dance a bit more but it also creates lots of heat and that is no good!! Keep it clean and mean. JMHO. I am no radio expert but the issue you speak of I have dealt with a few times while using export radios using Mosfets.
These days it's almost just as well to find a good used HF radio and have it opened up. Less freq drift and a lot cleaner output. Illegal is illegal, so might as well do it right. Again, JMHO. Have a good day.

 

[AC9BX]

Exactly, MOSFETs are not fragile with regard to VSWR per se. It depends greatly on the device being used and how so. A typical CB set, manufactured in compliance with FCC rules (varies for whomever wherever) is required to have the final output device feature an average power dissipation maximum of 10 Watts. Full modulation full AM with standard carrier will yield 16 Watts at peak. A consumer class radio, designed to keep the price down and have a small box, will not be over-built and in the case of the FCC must meet the requirement. That means the output device may not be very forgiving of a mismatch because it's already operating near its maximum, there's no room to build in headroom. And it may indeed be intended for other uses such as switch mode power supplies instead or RF.

LD MOSFET RF transistors from companies such as NXP and Microsemi have VSWR ruggedness that can handle mismatches well above anything they're likely to see, 50:1, 70:1, crazy stuff. These are the things in amateur and professional gear. Static discharge and overheating will kill these long before SWR.

 

[friskidog]

Anyone stop to think it was mentioned because it's the law....Just saying.
The comment in itself isn't really offensive and simply stated a fact. I agree Simple is better when it comes to hooking up a radio.
I had the misfortune of listening to channel 6 bleed across 3 bands on AM clear as day last week. I can't be sure but do you think they where running with an amp.......
73s

I assume anyone in this CB forum knows what's legal and not especially if someones asking about amps.
Just sayin

 

[Retroradio]

Maybe but there are also lots of posts of mbrs asking questions admitting they don't know and are new to radio so a friendly reminder now and then can't hurt. The spirit of radio is to help, inform and guide those that are new and not let them go down a slippery slope. At least that's how it was when I started in radio 40 years ago..... let's agree to disagree and be done with this before it degrades further into a Ham vs CBers thread which accomplished nothing.