Difference between SWR meters?

[weccwwe]

Hi all,

Going to buy a generic SWR/Power meter off amazon because I am working building my very first antenna.

This particular model is about $30

A guy at the local radio shop here is telling me that those suck because they introduce extra voltage into the SWR meter and throws off the sensitivity. I thought that it might be a little extreme in thinking because these units aren't even self-powered

But since I am very new to this, I thought that I would be better asking here if I could use that $30 one to tune my 146mghz and my 442mghz antennas

Or do I need to but a 210$ unit from his shop.

BTW, what is the difference between a 30$ and 210$ unit anyways?

Regards

 

[ScanWI]

Without know the models it is hard to saw what the exact differences are.

Here are several different things that can vary;

Frequency Range - make sure it covers the desired frequencies, most cheap ones are for the CB range

Calibration- has it been calibrated, can it be calibrated, does self-zero

Digital vs Analog

Selectivity- This can go hand in hand with sensitivity, I have seen some SWR meters that are extremely sensitive to nearby RF and others that ignore it. You want the one that doesn’t ignore it.


One option is to buy a watt meter instead, then you can test the forward power going into the antenna and the reflected. You can use these measurements to calculate the SWR and Return loss.



Sent from my iPhone using Tapatalk

 

[prcguy]

If the $30 meter is rated for the frequency range you want to play, then it should give you an indication of when your antenna is tuned even though it may not be considered a lab standard.

 

[weccwwe]

Was thinking about this one, http://a.co/d/gmdxMqZ

Reading what you guys are writing about, this might actually be the wrong one for me.

Great thing that I am asking here first

You guys might have a better solution for my very first meter for 146 & 442 for a brand new newbie like myself. I am building 2 JPoles, one for each intended frequency. 1/2" copper pipe, and using Youtube and antenna calculator for guidance.

Regards

 

[FKimble]

Yep, per your link, "Designed to test any 50 ohm antenna and antenna coax used for CB operation"
Not for 2m/70cm.
What model SWR meter is your friend at the local radio shop pushing, I mean selling? A two-way shop or a CB shop?

Frank KK4YTM

 

[SteveSimpkin]

Was thinking about this one, http://a.co/d/gmdxMqZ

Reading what you guys are writing about, this might actually be the wrong one for me.
....
I am building 2 JPoles, one for each intended frequency. 1/2" copper pipe, and using Youtube and antenna calculator for guidance.

Agreed that this is the wrong model SWR/Power Meter for your needs. Something like this model would probably do what you need for about the same price:
https://www.amazon.ca/Signstek-Prof...1540943378&sr=8-3-fkmr1&keywords=2m+swr+meter

Also I believe most J-Poles that are made for the 2m 144 MHz band will also work well on 70cm 440 MHz band. You may only need to make one 2m J-Pole antenna for your case.
https://www.jpole-antenna.com/shop/2-meter-amateur-radio-j-pole-antenna/

"Dual Band Performance in a single antenna:
Each antenna is individually tested and tuned for optimum performance on their respective bands. The two meter antenna is tuned to 146MHZ (1.2:1 SWR or less at 146MHz), and the SWR is 1.4:1 or less throughout the entire 2 meter band. This antenna also works great as a dual band antenna. The antenna will tune up on 70cm for excellent dual band performance."

 

[majoco]

Calibration (or lack of?) for the SWR portion is easily done with few home made dummy loads - you probably only need to make three, 50ohms, 100ohms and 200ohms, and solder them across PL259 plugs. You can't buy 50ohm resistors so two 100ohms in parallel will do and two in series for the 200 ohms. These will give you SWR's of 1, 2 and 4. Most electronic supply houses will sell 2% tolerance resistors which probably exceed the specification of your meter - you can check the actual value with a digital meter to test. How do you propose supplying the RF power - you won't need much more than 10watts and the sensitivity of the meter goes up with increasing frequency, so buy resistors with a sufficient power rating. NOT wirewound - must be non-inductive. I made a 100watt load for HF only from 44 2.2kohm 2 watt resistors and it has survived many overloads! (so far.....?)

How to calibrate the power meter is a totally different thing and rather more difficult. You'll need a voltmeter or oscilloscope capable of measuring the frequencies you are applying with a suitable Tee-adapter, your dummy loads and short length of coax with the right plugs. There is probably only one calibration adjustment so an HF power source of a few watts will do - you have to be happy with all the other frequencies! You may have to brush up on your maths to calculate the power in the load from the voltage across it and also be aware of how the meter reads AC volts - RMS, peak, average - who knows...?

Have fun!

 

[K4EET]

One consideration on this model:

https://www.amazon.com/Signstek-Professional-Standing-Wave-Meter-Testing/dp/B00GNVJ8IU

This SWR/Power meter is ONLY for VHF (140-150 MHz) and UHF (430-450 MHz) frequencies. It does not cover HF (1.8-30 MHz) if you ever needed that range. The power rating is 200 Watts maximum.

Do you also need the HF range of frequencies?

Dave

 

[weccwwe]

One consideration on this model:

https://www.amazon.com/Signstek-Professional-Standing-Wave-Meter-Testing/dp/B00GNVJ8IU

This SWR/Power meter is ONLY for VHF (140-150 MHz) and UHF (430-450 MHz) frequencies. It does not cover HF (1.8-30 MHz) if you ever needed that range. The power rating is 200 Watts maximum.

Do you also need the HF range of frequencies?

Dave

Hi Guys,

Really cannot thank you enough for all your input here, learned something new about what I really need for my first SWR meter, You all are great!

K4EET, I am only doing the UHF/VHF, and my radio output is rated at 50watts for each frequency, so this one you selected is right up my alley

Thanks again

Regards

 

[K4EET]

weccwwe,

Glad we could help you out. Let us know if you have any other questions. Have a GREAT day!

Cheers! Dave