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SWR scan on three different antennas


markskjerve

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I picked up a NanoVNA-H4 analyzer and ran a quick sweep of three antennas I have. A Comet GP-6NC dual band (GMRS/MURS) with 50ft of 400MAX cable, a N9TAX dual band (GMRS/MURS) Slim Jim and a KB9VBR GMRS J-Pole with 25ft of RG-213. Here are the results, first time using the NanoVNA and there are lots of other options to play with but will take a bit of time to learn them all. I will say the Comet is perfectly tuned for GMRS.

Comet GP-6NC
1.07 VSWR at 462.5 Mhz
1.06 VSWR at 467.5 Mhz

N9TAX dual band Slim Jim
1.30 VSWR at 462.5 Mhz
1.30 VSWR at 467.5 Mhz

KB9VBR GMRS J-Pole
1.75 VSWR at 462.5 Mhz
1.35 VSWR at 467.5 Mhz

 

 

comet.jpg

SlimJim.jpg

Jpole.jpg

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The J-Pole appears optimized for repeater access.

Curious about the jitter/static in all three sweeps between 465 and 467MHz.

As an FYI: The NanoVNA H2/H4 are third party clones possibly using cheaper parts. The only official NanoVNA are from https://nanorfe.com/nanovna-v2.html

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As of November 2022 there are many clones of an outdated hardware version sold under various names with exaggerated specs, which are highly noisy due to using incorrect or lower quality parts, while using measurements and graphs from original equipment to deceive unaware customers. Some users have also reported software incompatibility. See official stores above and look for NanoVNA V2 Plus4 and VNA6000 versions only to avoid getting a bad clone.

Beware that nanovna .com is not owned by the original developers of either V1 or V2 NanoVNAs, and is being used to mislead users into buying clones from one clone manufacturer. These clones are not supported by any updates from the developers.

The following stores have sold at least one bad clone.

  • Banggood
  • Eleshop
  • R&L electronics - still selling clones despite being asked not to by the original developers

 

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44 minutes ago, KAF6045 said:

The J-Pole appears optimized for repeater access.

Curious about the jitter/static in all three sweeps between 465 and 467MHz.

Not sure if the jitter/static is from a tower about a block away from me or because I have a 6 inch USB-C cable plugged into the VNA to the computer or that I just need to play with the options a bit more. I do have a few signals in the 466Mhz range that are strong enough that I can pick them up on a 935G HT with no antenna attached.

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34 minutes ago, KAF6045 said:

 

As an FYI: The NanoVNA H2/H4 are third party clones possibly using cheaper parts. The only official NanoVNA are from https://nanorfe.com/nanovna-v2.html

 

What crap. 
First there was a design in the USA that was open source. 
The some other people in the USA improved that design. 
Then a guy in Japan improved that design. 
Then a guy in China took that design and created a commercial product but he also made the software and hardware open source. However they tried to claim both proprietary design while taking advantage of improvements made by users. 
Other companies have taken that design and modified it, sometimes for the better and sometimes not, but to claim that everyone else is somehow violating their original design is an exaggeration. Casting aspersions by speculating that the “clones” could be constructed of lower quality components is simply innuendo. 

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51 minutes ago, Sshannon said:

What crap. 
First there was a design in the USA that was open source. 
The some other people in the USA improved that design. 
Then a guy in Japan improved that design. 
Then a guy in China took that design and created a commercial product but he also made the software and hardware open source. However they tried to claim both proprietary design while taking advantage of improvements made by users. 
Other companies have taken that design and modified it, sometimes for the better and sometimes not, but to claim that everyone else is somehow violating their original design is an exaggeration. Casting aspersions by speculating that the “clones” could be constructed of lower quality components is simply innuendo. 

I read something about cheap knockoffs before buying. I didn't want to order from China but from a reputable dealer. So I ordered mine (NanoVNA-H4) for around $100 shipped from R&L Electronics and it came in 3 days. Fair price from a highly rated dealer.

I did attempt to pull a SWR sweep on a Nagoya NA-771G HT antenna but trying to test a HT antenna on a NanoVNA is close to impossible from what I've gathered on internet. It's hard to compensate for the ground plane of the radio itself since its not attached to the radio. I did a SWR sweep with a 6 inch jumper and holding the antenna at the connector in my hand and pulled a SWR of around 3.0 across the band. If I just let it dangle from the jumper it was 6.0 to 8.0! 

For the price, its a neat tool to play with for external antennas, but for HT antennas it's kinda useless. But then again, I've only had it for a day.

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1 hour ago, markskjerve said:

I read something about cheap knockoffs before buying. I didn't want to order from China but from a reputable dealer. So I ordered mine (NanoVNA-H4) for around $100 shipped from R&L Electronics and it came in 3 days. Fair price from a highly rated dealer.

I did attempt to pull a SWR sweep on a Nagoya NA-771G HT antenna but trying to test a HT antenna on a NanoVNA is close to impossible from what I've gathered on internet. It's hard to compensate for the ground plane of the radio itself since its not attached to the radio. I did a SWR sweep with a 6 inch jumper and holding the antenna at the connector in my hand and pulled a SWR of around 3.0 across the band. If I just let it dangle from the jumper it was 6.0 to 8.0! 

For the price, its a neat tool to play with for external antennas, but for HT antennas it's kinda useless. But then again, I've only had it for a day.

I bought mine from R&L also. Mine is a model that received good reviews. Later, I discovered the claims about clones. 

The one I have has some nice hardware advantages, such as N connectors rather than SMA. 

I trust R&L more than I trust the company making wild accusations. 

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8 hours ago, Sshannon said:

I bought mine from R&L also. Mine is a model that received good reviews. Later, I discovered the claims about clones. 

The one I have has some nice hardware advantages, such as N connectors rather than SMA. 

I trust R&L more than I trust the company making wild accusations. 

When I ordered up the Comet GP6 antenna from DX Engineering I knew I needed at least a Type-N to UHF/SO-239 adapter for the KG1000+ (antenna is Type-N) and had plans to buy the NanoVNA once the antenna came in. DX Engineering had "all gender" Type-N to UHF/SO-239 kit (4 piece adapter package) for $20 that allows me to have any gender (Type-N male or female and SO-239 male or female) at the end of the cable. Another $20 got me the same kit but for Type-N to SMA. I'm covered on hooking up any of my antennas to a radio, HT, or the NanoVNA. 

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1 hour ago, markskjerve said:

When I ordered up the Comet GP6 antenna from DX Engineering I knew I needed at least a Type-N to UHF/SO-239 adapter for the KG1000+ (antenna is Type-N) and had plans to buy the NanoVNA once the antenna came in. DX Engineering had "all gender" Type-N to UHF/SO-239 kit (4 piece adapter package) for $20 that allows me to have any gender (Type-N male or female and SO-239 male or female) at the end of the cable. Another $20 got me the same kit but for Type-N to SMA. I'm covered on hooking up any of my antennas to a radio, HT, or the NanoVNA. 

That’s what I’ve done also.  I picked up a UHF to almost anything adapter kit from R&L when I bought the NanoVNA and I purchased an SMA adapter kit with my SDR Kit and separately I bought a general purpose SMA kit.  I still find an oddball connector combination but usually I can put together some way to adapt.

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26 minutes ago, Sshannon said:

That’s what I’ve done also.  I picked up a UHF to almost anything adapter kit from R&L when I bought the NanoVNA and I purchased an SMA adapter kit with my SDR Kit and separately I bought a general purpose SMA kit.  I still find an oddball connector combination but usually I can put together some way to adapt.

I'm currently shopping around for a PC based SDR transceiver that can do GMRS. I'm hoping to find a deal on one on Black Friday or we have the Tampa Hamfest coming up in a few weeks and see what kinda fun stuff they may have. I've been addicted to playing with SDR receivers at websdr.org. Do you know of something I should be looking for? Looking at a Pluto+ at the moment.

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37 minutes ago, markskjerve said:

I'm currently shopping around for a PC based SDR transceiver that can do GMRS. I'm hoping to find a deal on one on Black Friday or we have the Tampa Hamfest coming up in a few weeks and see what kinda fun stuff they may have. I've been addicted to playing with SDR receivers at websdr.org. Do you know of something I should be looking for? Looking at a Pluto+ at the moment.

I’m sorry, I don’t.  I just bought a small SDR (receiver only) to play with.  I’ll be watching to see what you do!! ?

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Let's make it a SWR scan on 4 antennas. Picked up a MFJ 1868 Discone antenna that is supposed to do TX/RX from 50mhz to 1.3Ghz at 200 watts more for a scanning antenna than GMRS but had to run a sweep on it anyway since it could TX on GMRS. Discones are really weird. Looks like a sine wave from 420mhz to 470mhz but SWR never get above 1.6 to 1. 

 

discone.jpg

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