Trying to find out how to properly measure antenna SWR and Watt readings

[popnokick]

Unless you are planning to add-on an RF power amplifier that will cost many more times than the FT-8900R did (and run 10x or more the RF output power of which the FT-8900R is capable of).... your FT-8900R and its 50W RF output is going to be FINE on your 1/4 wave ground plane made from an SO-239 connector (assuming you don't short the center conductor to the shield or some other unintentional mistake while making the antenna / feed line / coax connectors). You do plan to mount the antenna outdoors, right? (I scanned back through this long thread but couldn't find that info right away.) If you're putting it indoors get it up high.... like the attic or crawlspace... and away from people to eliminate MPE concerns... as well as to have the antenna operate a whole lot better.
PS - The FT-8900R is a quad band (10M, 6M, 2M, 70cm) radio. Hopefully you realize that a 19" ground plane will be fine on 2M / 70cm.... but useless on the 6M and 10M bands in that radio(?).

 

[prcguy]

Wire size and power handling on an HF antenna is different than an VHF/UHF antenna because the current is spread out over a larger area on the HF antenna and for a 2m ground plane it would be most intense in the first 6" or so. With that said, 1/6" brass rod should handle 100 watts and probably much more without any trouble.

I have some cheap 2m/70cm mag mount antennas with whips made from thin black coated steel wire and they get hot at 25 watts because steel is not a good conductor for antennas.

What determines the amount of power it's possible to feed an antenna is/are the insulators used in making that antenna. The size of conductor, the wire/rod/tube size doesn't make that much difference. What's used as insulators can and certainly do make a difference. Even so, it's all 'relative', you gotta factor all of the abilities of the things use into "will it stand that much?". I've used #18 wire for antennas and it didn't 'melt' with full legal limit. There are huge differences between mechanical abilities and electrical abilities...

 

[LostSignal]

Unless you are planning to add-on an RF power amplifier that will cost many more times than the FT-8900R did (and run 10x or more the RF output power of which the FT-8900R is capable of).... your FT-8900R and its 50W RF output is going to be FINE on your 1/4 wave ground plane made from an SO-239 connector (assuming you don't short the center conductor to the shield or some other unintentional mistake while making the antenna / feed line / coax connectors). You do plan to mount the antenna outdoors, right? (I scanned back through this long thread but couldn't find that info right away.) If you're putting it indoors get it up high.... like the attic or crawlspace... and away from people to eliminate MPE concerns... as well as to have the antenna operate a whole lot better.
PS - The FT-8900R is a quad band (10M, 6M, 2M, 70cm) radio. Hopefully you realize that a 19" ground plane will be fine on 2M / 70cm.... but useless on the 6M and 10M bands in that radio(?).

I know it's a quad and I do plan on using it outside. Next Field Day, I'm going to try to get my "radio box" complete or 90-99% complete by then. One of the main reasons why I started this thread with the SWR question and antenna building. I'm starting with a simple 2m vertical so I can learn the very basics and move on to more intricate designs, if you will, as I learn and progress.






Many HAMs despise CB, but I don't care as RF is RF to me and for SHTF or emergency purposes, any RF is important, as far as I'm concerned. But yeah, that is my radio box I've been working on. It's going to have multiple power options regarding charging the batteries and supplying power to external devices as well. I wanted a radio box that had as many different bands as possible, for me at least. It's my "5 bander" plus "instant" NOAA capability on the CB.

So yeah, this thread is a how to use a SWR meter, build an antenna, and any related questions. At least, that is what I was shooting for?.

So far, thank you guys for taking the time for your input. I'm learning quite a bit, even just the smallest details count as learning as well.

 

[cmdrwill]

This ground-plane antenna calculator should help.

1/4 Wave Ground Plane Antenna Calculator – M0UKD – Amateur Radio Blog

I use brass tubing with a 3/16 or 1/4 inch dia., the larger diameter provides a wider frequency range. I even have a really broad band ground plane with 1/2 " copper pipe, 130 to 170 mhz.

 

[LostSignal]

This ground-plane antenna calculator should help.

1/4 Wave Ground Plane Antenna Calculator – M0UKD – Amateur Radio Blog

I use brass tubing with a 3/16 or 1/4 inch dia., the larger diameter provides a wider frequency range. I even have a really broad band ground plane with 1/2 " copper pipe, 130 to 170 mhz.

HAHAHA, that's the same calculator I'm using as well.

I didn't know that about the tubing sizes??? Interesting!!!

 

[W5lz]

I had to try that 1/4 wave calculater and have to agree it's pretty close. It's also based on that magic 1/4 wave number of '234' +/- a bit according to that VF you may have plugged in. Unless you happen to live in a "perfect" place, the calculator or '234' number are going to get you close and still need a tweak or two (length(s) adjustment) to get it close to what you will settle for. None of this is ever exact, just too many variables.

 

[LostSignal]

I had to try that 1/4 wave calculater and have to agree it's pretty close. It's also based on that magic 1/4 wave number of '234' +/- a bit according to that VF you may have plugged in. Unless you happen to live in a "perfect" place, the calculator or '234' number are going to get you close and still need a tweak or two (length(s) adjustment) to get it close to what you will settle for. None of this is ever exact, just too many variables.

Well, going to find out here pretty shortly.

Started assembling my 2m and will be posting my "build" as a step by step, with pictures, of what I did.

I got my radio box out of storage yesterday.

Likely it won't be until next week of me doing this, that is my posting, but during this time until then, I will be working on it though.

I MIGHT have some questions, but I think everything has been answered to do this build?

My only issue is finding a way to make a mounting bracket to mount it to a pole fixture? As much as possible, I try to come up with my own ideas, in that sense.

Anyways... thank you guys and can hardly wait to show my first antenna build, good or bad...

 

[LostSignal]

Actually, I DO HAVE this particular question, I plan on testing my antenna with my SWR meter on "144.000" and "148.000" to view the extreme ends of the 2m band. I only plan on literally transmitting those 2x freq and nothing else.

My question, when I set my radio on "144.000", for example of the lower freq, do I still announce my call sign??? As well as when I set my transmitter on "148.000", do I announce my call sign???

I will likely be doing this in fairly short bursts just so that I can see/view my SWR readings during "tweaking" and/or viewing the performance of my antenna?

 

[nd5y]

My question, when I set my radio on "144.000", for example of the lower freq, do I still announce my call sign??? As well as when I set my transmitter on "148.000", do I announce my call sign???

Legally you are not allowed to make unidentified transmissions.
144.0 and 148.0 are band edges so assuming your radio is dead on frequency your signal would be half outside the amateur band and could potentially interfere with federal users.
144.0-144.1 is limited to CW only.
If you want to be legal then the highest and lowest frequencies you can use 20 kHz wide FM on are 144.11 and 147.99.

You could get an antenna analyzer and not have that problem.

 

[LostSignal]

I did figure the "not allowed" part, but was wondering how it is done when people make their antennas and/or what the procedures are when testing the "new" antenna? I really didn't know how else to ask the question, but you definitely answered it!

Thank you kind sir for teaching a noob.

 

[Ubbe]

The initial reason for announcing your call signal, and basestations to CW their ID, are that if your transmission interfere with other equipment it could be easier to identify the source. It probably was more critical in the old days when people built their own transmitters but now amateurs buy their gear and the only technical part are to plug it in. But as I understand your are allowed to use non FCC certified transmitters so the requirement to give your call sign at the start of a transmission and then periodically could still have its value.

/Ubbe

 

[LostSignal]

The initial reason for announcing your call signal, and basestations to CW their ID, are that if your transmission interfere with other equipment it could be easier to identify the source. It probably was more critical in the old days when people built their own transmitters but now amateurs buy their gear and the only technical part are to plug it in. But as I understand your are allowed to use non FCC certified transmitters so the requirement to give your call sign at the start of a transmission and then periodically could still have its value.

/Ubbe

Again, thanks to ALL for your input!!!

I have my radiating element cut, ground radials cut, and I THINK I have a temporary solution for my mount.

I soldered the vertical to the UHF chassis connector and just need to solder my ground radials.

I'll be posting pictures soon as well as the initial SWR readings I get. I got my radio box, but need to dig out from my storage bin my Astron SS-10 power supply.

Finally, I plan on going to the local mountain top here, Santiago Peak, and doing some testing up there as well. That's the plan at least.

Anyways, if you guys like, I'll post my build soon?

 

[cmdrwill]

I plan on going to the local mountain top here, Santiago Peak, and doing some testing up there as well

Do not think that you will be able to test any antennas on STAGO Pk WAY too much RF up there. Your SWR meter will peg before you even get to the top.

 

[prcguy]

Santiago is the second worse hill in So Cal for interference with Mt Wilson being #1. You will be lucky to get any amateur radio to work up there without some decent external filtering. Since the OP is in So Cal, I can test his new antenna on some of my antenna analyzers if he is not too far away.

Do not think that you will be able to test any antennas on STAGO Pk WAY too much RF up there. Your SWR meter will peg before you even get to the top.

 

[LostSignal]

Do not think that you will be able to test any antennas on STAGO Pk WAY too much RF up there. Your SWR meter will peg before you even get to the top.

Santiago is the second worse hill in So Cal for interference with Mt Wilson being #1. You will be lucky to get any amateur radio to work up there without some decent external filtering. Since the OP is in So Cal, I can test his new antenna on some of my antenna analyzers if he is not too far away.

I need to clarify, I didn't mean at the peak as the access is unavailable anyways since the fires, but good point either way with the towers.

I was more along the lines of thinking about halfway up to the peak at a big open lot I like to call "The Parking Lot". If you're coming from the 5fwy side, about halfway up the peak there is that big open lot if you've ever been up there, you will likely know what I'm referring to.

I don't think the interference is going to be of bother in that open lot. I do night runs up there when I need to get my "dirt fix" and it is now, technically, "desert season" so I MIGHT be going out to the desert, at least once, before x-mas. All depends?

Anyways, sorry for the confusion as that is what I meant by going up Santiago Peak.

The picture below is AT the towers all the way up the peak... and ever since dirt-bag started those fires, it's been closed from public access. I heard rumors that they actually MIGHT open the gates at the end of this year, but I SO doubt it!!! In that parking lot I was talking about above, you can pretty much see how close the fires came to the towers... pretty DAMN CLOSE!!! Anyways...


Overlooking Orange County... WAY OFF in the distance to the right is Disney Land... HAHAHAHA, when they have their fireworks show, you can barely see it, but yet you know the fireworks are HUGE when up close in person!!! Crazy how SMALL the fireworks are when seen from the peak.


Btw, I have my radials done (NOTE: just need to mount them and bend down to the 45deg level), the vertical done, and will be doing my temporary mount tomorrow at work during my lunch. I'm using my OLD CB mount and need to bore the CB lug hole to roughly 5/8" or so for the SO-239 connector to fit. I will come up with a different mount later OR I just MIGHT keep this mount setup if it works out pretty good?

Anyways, I'm very close to being done and will start my initial tests within a day or two?

That reminds me, I NEED to find my Astron power supply??? HAHAHAHAHA

 

[majoco]

There's no point in announcing your call on a frequency that you're no going to use. Go back home, put up your antenna, check the VSWR at the ends of the bands you intend/allowed to use use, adjust your radials to get the good VSWR over that bit of the band. Job done. Lets not over complicate this relatively simple operation.

 

[LostSignal]

There's no point in announcing your call on a frequency that you're no going to use. Go back home, put up your antenna, check the VSWR at the ends of the bands you intend/allowed to use use, adjust your radials to get the good VSWR over that bit of the band. Job done. Lets not over complicate this relatively simple operation.

First off, I do plan on adjusting my SWR at home. Secondly, the plan was to go to the local mountain "top" after to do my "field setup". Lastly, what is wrong with me asking a few questions since this is my first time doing this???

Thank you anyways for your input.

 

[KE5MC]

LostSignal,
Nothing wrong with your questions. In the beginning book learning does not fill the gaps like trial & error and hands-on cause & effects does. We sometimes forget all the questions we had when starting as a profession or a hobby or both. Questions are a good backstop to hands-on effort. I'll only add transmit in band where allowed for the mode and privileges' you have and use you callsign. Usually something has to be said depending on mode or If you want to see variations in power supply voltage or current as your talk. "callsign" does just as well as "testing 1,2,3..." and meets requirements and dummy loads can be surprising leaky.
Have FUN!
Mike

 

[LostSignal]

LostSignal,
Nothing wrong with your questions. In the beginning book learning does not fill the gaps like trial & error and hands-on cause & effects does. We sometimes forget all the questions we had when starting as a profession or a hobby or both. Questions are a good backstop to hands-on effort. I'll only add transmit in band where allowed for the mode and privileges' you have and use you callsign. Usually something has to be said depending on mode or If you want to see variations in power supply voltage or current as your talk. "callsign" does just as well as "testing 1,2,3..." and meets requirements and dummy loads can be surprising leaky.
Have FUN!
Mike

Yeah, with all due respect to the other poster, I'm not trying to make this complicated, but at the same time I can't afford a $10k fine either. When I got my license, everything was already built and ready to use. This is different in the sense that I'm making something from "scratch" and for all I know, I did something wrong while building the antenna???

Anyways, moving on, another poster gave good advise when it came down to the extreme band ends. The idea, as you guys will see once I post the pictures, of why I have been asking these questions to begin with along WITH making sure I'm using my SWR meter correctly. There are "behind the scenes reasons" for my questions and I definitely have experience with a product development process. My old boss NEVER just made something, did quick tests, called it good.

With that said, this is something new to "ME" that I am doing and just simply gathering as much information as I can to learn and do. The reason I started with one of the simplest antenna designs so as to fully understand the theory of ground planes, measurements, etc etc etc. Knowing the very basics and understanding them is key to progress to the more involved designs as one learns, in my humble opinion.

Finally, I thank EVERY ONE for taking the time for their input and advice!!! I have learned quite a bit AND I need to get my Gordon West book out of my storage unit to review some things, mainly the rules/regulations.

I'll be posting pictures soon for sure.

Btw, found my Astron power supply. I forgot to bring my OLD CB mount to work on during lunch today, so I just wasted a day. Pretty upset at myself for forgetting.

Annnnnyways...

 

[W5lz]

"...I have some cheap 2m/70cm mag mount antennas with whips made from thin black coated steel wire and they get hot at 25 watts because steel is not a good conductor for antennas. "
I think you said the problem with that 'cheap' thingy. Steel will handle RF/power just fine. If it gets hot then look for another problem.