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Posted

NanoVNA is nothing less than miraculous piece of equipment, but it has drawbacks. The biggest: it is extremely unfriendly for newbies. The second: it can't measure power. And the third: screen sucks, or you must use PC, that is also may not be convenient. True, you can't find better tool for $50. But you must know how to use it.

Posted

NanoVNA is nothing less than miraculous piece of equipment, but it has drawbacks. The biggest: it is extremely unfriendly for newbies. The second: it can't measure power. And the third: screen sucks, or you must use PC, that is also may not be convenient. True, you can't find better tool for $50. But you must know how to use it.

That’s why I said what I said that guy must be a doctor because as far as I know the man was looking to measure his power and swr ....Not try to figure out how to use it spend the money on the link I posted you will be at ease ....Had mine for a year now and leaves it in line works and tells the truth.

 

 

Sent from my iPhone using Tapatalk

Posted

Doctor knows? haha... certainly knows when something is garbage... 

 

The NanoVNA is what it is. If there is a will, there is a way, and Youtube is full of tutorials on how to use it.

 

I recommend NanoVNA V2 with the 4.3" screen... it sweeps faster, and goes easier on your eyes.

 

You can measure power using a calibrated attenuator... low power is easy, like 5W, etc, but for something like 500 watts, you'll need a lot of dB attenuation to test it.

 

G.

Posted

Doctor knows? haha... certainly knows when something is garbage... 

 

The NanoVNA is what it is. If there is a will, there is a way, and Youtube is full of tutorials on how to use it.

 

I recommend NanoVNA V2 with the 4.3" screen... it sweeps faster, and goes easier on your eyes.

 

You can measure power using a calibrated attenuator... low power is easy, like 5W, etc, but for something like 500 watts, you'll need a lot of dB attenuation to test it.

 

G.

Very newbie here. How would one measure power using a calibrated attenuator... I to and looking for a SWR meter but am seeing that the NanoVNA might work and then some, but I dont want to miss out on features that are on a SWR (reflected power, power output) that I might need,  or do I need them? I have an HT  BF-F8HP that will be connected to a car roof mount antenna (might be either Comet CA-2X4SRNMO or Browning BR-450 UHF).

 
Posted

So, they way I've done this was using a preselector tuned to a far away frequency (a VHF one used for UHF, most of those will provide about 80-90 dB of isolation). But you should use a real attenuator (the Preselector has very high SWR when tuned off frequency),

(like this https://www.ebay.com/itm/JFW-60-dB-25-W-inline-attenuator-N-Connectors-50FHC-060-25/324149401708?hash=item4b78cf586c:g:hOwAAOSw2qpcTkcy ) remember it needs to be a large one, a small 6-10dB one will not be enough. 

 

Plug both ends of the NanoVNA to measure the dB attenuation at the frequency, either for the preselector or the attenuator.

 

After that, plug the radio on the other side of the attenuator (Should look like this: NanoVNA port S21 ---> Attenuator ----> Radio you want to test. ) Put a 50 Ohm dummy load on the S11 port of NanoVNA. Key the radio, you'll see the readings go up, from noise floor to some figure, subtract the attenuation from this figure, and that will give you a good estimate of the power.

 

NanoVNA will also calculate SWR, you just plug the S11 port to the antenna, where the radio would go, and you'll see the the curve with the SWR (or return loss), impedance, etc... which will tell you if the antenna needs to be shorter or longer.

 

G.

Posted

Well, you think its the wrong answer, and I just don't. So... to each his own.

 

G.

 

Newbies may also start with Maxwell equations (https://en.wikipedia.org/wiki/Maxwell%27s_equations). Learning is good, right? It's like a dancing lesson offered by Lord!

 

Snark off: I still think that when somebody asks about "decent cheap SWR meter" the NanoVNA is a wrong answer. With all due respect to the NanoVNA and those who offered the advice.

Posted

Newbies may also start with Maxwell equations (https://en.wikipedia.org/wiki/Maxwell%27s_equations). Learning is good, right? It's like a dancing lesson offered by Lord!

 

Snark off: I still think that when somebody asks about "decent cheap SWR meter" the NanoVNA is a wrong answer. With all due respect to the NanoVNA and those who offered the advice.

 

 

5577857e4b5257c138b71a07bb4eba17.jpg

As a repeater owner don’t think this is to hard to read with eyes

 

 

Sent from my iPhone using Tapatalk

Posted

Well, you think its the wrong answer, and I just don't. So... to each his own.

 

G.

 

 

Newbies may also start with Maxwell equations (https://en.wikipedia.org/wiki/Maxwell%27s_equations). Learning is good, right? It's like a dancing lesson offered by Lord!

 

Snark off: I still think that when somebody asks about "decent cheap SWR meter" the NanoVNA is a wrong answer. With all due respect to the NanoVNA and those who offered the advice.

And I'm certain that the first device you used to check an antenna's efficiency was an antenna analyzer. People usually learn to crawl before they do handsprings with advanced level equipment such as the Vector Network Analyzer.

Posted

Well, I am sorry if I disagree with this, but NanoVNA is hardly an advanced piece of equipment. Takes watching one Youtube video to know all you need to know about it for a beginner... 

 

And my first "SWR meter" was a Times T100+ vector analyzer (still have it) I remember the needle SWR meter thingies at some ham meet up and I was like... yeah... there has to be a better way... and indeed there was.

 

G.

  • 4 weeks later...
Posted

Stirring up the stinky pot:

 

Is a dummy load recommended for checking SWR on HT?  I love dummy questions.

 

Next:  Anyone care to share a list of recommended tools to build/modify cable?  Looks like I'll be doing a few installs of my own plus some other folks rigs.

 

Thanks.

Posted

Stirring up the stinky pot:

 

Is a dummy load recommended for checking SWR on HT? I love dummy questions.

A dummy load is required when you want to get accurate power measurements from your power meter. A dummy load can help confirm your SWR meter is (at least partially) calibrated. A good dummy load connected to the output of the SWR meter (in place of the antenna) should cause the SWR meter to always read 1:1. If it does not, you either have a defect meter or a defective dummy load.

 

No question is a dumb question if you don’t know the answer to it.

 

 

Michael

WRHS965

KE8PLM

Posted

A dummy load is required when you want to get accurate power measurements from your power meter. A dummy load can help confirm your SWR meter is (at least partially) calibrated. A good dummy load connected to the output of the SWR meter (in place of the antenna) should cause the SWR meter to always read 1:1. If it does not, you either have a defect meter or a defective dummy load.

 

No question is a dumb question if you don’t know the answer to it.

 

 

Michael

WRHS965

KE8PLM

 

 

Any preferences? 

https://www.gigaparts.com/mfj-261.html

Posted

You get what you pay for. If you have cheap radios then using a cheap meter isn't going to help much. Spend a bit more on the equipment you need to test and you will be pleased. Most likely youll also find all this cheap stuff is not going to perform well enough.

I agree. I'm looking to spend part of my stimulus check on a good Bird Model 43 meter myself. I want something I can trust mainly for RF power measurements. The forward and reverse power can be used to calculate SWR if necessary. The Diawa CN-103 I purchased new years ago gives me readings I just don't believe or trust.

 

https://www.dxengineering.com/parts/dwa-cn-103m

Posted

I let 2 Birds fly away from my old job.  They simple RNA/DNA/RIF.. shit-canned them and I let it happen.  Also a dozen Motorola 462 UHF repeaters from our mtn top microwave sites, and HTs.  I guess it would have been 'theft' but I know they went in a pile.  Lots of test gear went away when we moved to fiber.

I agree. I'm looking to spend part of my stimulus check on a good Bird Model 43 meter myself. I want something I can trust mainly for RF power measurements. The forward and reverse power can be used to calculate SWR if necessary. The Diawa CN-103 I purchased new years ago gives me readings I just don't believe or trust.

 

https://www.dxengineering.com/parts/dwa-cn-103m

  • 3 weeks later...
  • 2 weeks later...
Posted

Which adapters or pigtail will I need with the SureCom SWR to check mobile radio SWR?  It looks like it comes with SMA adapters but nothing for mobile.

 

Thanks.

 

If you're talking about a typical mobile (with antenna connectors that look like the old CB radio type), for the SW-33, you need a set of UHF to SMA adapters like these

https://www.amazon.com/gp/product/B01MQNJVMT

 

For the SW-102, it depends on where you source it.  Some options come with a pair of UHF adapters, but they both appear to be UHF Female "SO239" (antenna connector side) like these:

 

2021-04-13_15-08-56.png

 

If you get one that comes with those adapters (like this one:  https://www.amazon.com/Mcbazel-Surecom-Digital-125-525Mhz-Antenna/dp/B01D86IKIQ/) then you still need one to go to the radio side (N Maile to UHF Male) like this one: https://smile.amazon.com/DGZZI-2-Pack-Coaxial-Adapter-Connector/dp/B06ZZRL2C9

 

Here's a diagram that I hope is correct and makes sense:

 

2021-04-13_15-24-29.png

 

The other option is to use a jumper cable like this:

 

2021-04-13_15-36-57.png

Posted

OK I'm jumping in on this bandwagon.   I tend to go overboard when I learn new stuff, so technical aspects don't worry me.  What does worry me, however are things like:

 

1. Requires a windows PC to function properly (I'm a Mac guy).  PITA drivers to install, com ports to configure with USB emulators with poorly written drivers, etc.

2. Requires 10 hours of study to accomplish a task I will perform once or twice a year, and thus I will have to repeat that 10 hours of study every year because I can't remember the details from the last time.

3. Expensive recurring costs of ownership like annual subscriptions or costly maintenance updates.

4. Spending more than I needed to because of some whiz-bang feature I'll rarely or never actually use

5. Requires babying and constant "re-tuning" or calibration before using (spend as much or more time tweaking as using)

 

(and yes, I regularly do all of these things, but I try now to avoid them!)

 

I had just ordered a Surecom SW-33 Mark II and then came across this thread, so I cancelled the order while I ruminate a bit.  I like information, and love data.  I love to optimize stuff.  But I don't see myself getting to the point where I'm going to have a bench with a bunch of oscilloscopes and soldering irons. (that was my Dad, who built Heathkit radios and TV sets when I was a kid back in the 70's)

 

Given all that, I feel like spending $50 on the Surecom SW-102  or $60-$70 NanoVNA seems like a reasonable step up in price from the $45 Sw-33 given the extra functionality.  Though looking at the video tutorials for the NanoVNA, it seems like overkill for me (violates rules 1, 2, 4, & 5 for me)

 

​I guess the real question is which of those options is most compliant for what I need (which I think is similar to the OP's original question).  "Which one is "good enough" in terms of accuracy, usability, and features?  There definitely seem to be some strong opinions, and if you spend time on forums, this sort of thing isn't uncommon (nor is it anything but well-meaning usually).  It's sorta like the following exchange:

 

 

​OP:  "Whats the best way to get from LA to NYC on a budget?"

 

Reply 1:  "Citation X  - it's faster than a Gulfstream G-650 and less than half the cost"

 

​Then a debate rages about the differences between the Gulfstream and the Citation, with the inevitable person saying "Hey, you guys don't know what you're talking about.  The Falcon 7x is a much better aircraft..  blah blah blah"

 

Then the original poster comes back and says

 

"I was wondering if Greyhound was cheaper and faster than taking the train..."

 

Its all about relative perspective...  :-)

 

Oh, PS - after some thought and a bit more reading, I went ahead and purchased one of the Surecom 120 units.  I'll bet it will do everything I'm likely to need for the couple of VHF/UHF radios I have. 

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