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Okay new quesetion #antennas #v6


Rene
 

Hello i am thinking to buy an NanoVna analyzer. Maybe somone has  experience with the Bitx and anayzing his antenna etcetc???
Regards
Rene
Netherlands


Curt
 

Rene

A nano VNA is inexpensive enough that I won't work hard to discourage you from buying one.

Let's just say you can build a good antenna for HF without one. An SWR meter can tell us if our antenna is to long or short. Very little inside a ubitx or bitx can be measured with one.

I work as an EE, been a ham for decades. Yes I will get one eventually.  But most hams do well without one. But if you are curious and want to learn, sure, get one.

73 curt wb8yyy


Herman Scheper <Hsrscheper@...>
 

Do it Rene. They are not very expensive. You need some time to learn how to do.
I am back in om business after 35 years other things and hobbies. In that time i used a big 5 el.rotary hf beam and worked the whole world with Kenwood and home build stuff. 
Now i build a Ubitx V5 and made some dipoles and end fed wire antennas. I used the Nanova to see how my antennas are end behave. Ibuild a 3.5-7 MHz and 14-21 Mhz dipole and my Nanova told me after installing the dipoles on which freq they have their resonance dip. So i can cut one and can also see what to do with the other one.
Very very good touse and have the Nanova. Without the result would be not so good.
You can find a lot of movies on youtube.  I bough one from Aliex. but Amazon.de have them too for a fair price..

Veel succes van Herman Scheper PA0BAB



Herman vanaf z'n IPad.

Op 15 apr. 2020 om 19:11 heeft Rene <rmvanb@...> het volgende geschreven:

Hello i am thinking to buy an NanoVna analyzer. Maybe somone has  experience with the Bitx and anayzing his antenna etcetc???
Regards
Rene
Netherlands


Bob Bennett
 

It will re-acquaint you with the Smith Chart, something you have always wanted :-) I got one because it measures VHF/UHF SWR. I have other SWR meters for HF. I will learn about +/-j and Smith charts now that I have one

Bob nz2z

--
Bob
NZ2Z


Rene
 

Okay to all thx for reply, and for Herman...ik ben ook weer begonnen na 35 jaar...nog geen N maar heb wel boeken en online cursus maar door drukte in huis door corona, kom ik er niet aan toe. Ben af en toe in de avand na eten een uurtje aan het soleren en knutselen. Endfed van Hfkits voor 10..20..40mtr en ben ook bezig net een interface voor de bitx  voor Ft8. Dus genoeg te doen en te ontdekken. Dank je wel voor de tip.
Groet, Rene,
Hoofddorp


John Faivre
 

I built a 20/40 dipole and was really struggling getting the resonance points where I needed them to be using my radio and SWR meter. I finally ordered a nanovna and was able to dial it in quickly hanging about 8 feet above the ground. Then when I hung it above my roof I needed to tweak it a bit more. Now my min SWR is right not the FT8 frequencies. I did not have to get into a lot of theory, just did SWR sweeps over selected frequency widths. Great tool for tuning an antenna. 
--
John Faivre WA9SGD


Rene
 

Okay nice John, i orderd 1😂😂


Russ KG0BK
 

As the antenna raised (or lowered) from ground . . . the impedance changes.
The closer to the ground . . .the lower the impedance. Higher from the ground . . . the greater impedance.
You need to adjust the antenna at the point you will be using it from.
Surroundings in the vicinity of the antenna will also produce various VSWR.
Russ  KG0BK


ajparent1/kb1gmx <kb1gmx@...>
 

Russ,

All true until you get high enough and it starts going down.

I'd describe it as higher the closer to 70 ohms (natural impedance for dipole).
Also at less than .25 lambda the impedance is lower than 50 ohms and the length
will be shorter due to ground reflection and loading.


Allison
---------------------------------
No direct email, it goes to bit bucket due address harvesting in groups.IO


Ralph Mowery
 

A SWR meter is all that is needed to adjust simple antennas.  However the nano VNA makes it easy to see where the antenna is resonate.  You can take them out to the antenna so you do not have to go to the shack to check the SWR.  Those things are really very accurate.  Much more so than you would think for an instrument under $ 100.  Go for the newer 4 inch screen .  They can also be hooked to a laptop for a large display.  If you have an extra $ 50 to $ 100 to spend I say go for it.

Ralph ku4pt


On Wed, Apr 15, 2020 at 1:11 PM Rene <rmvanb@...> wrote:
Hello i am thinking to buy an NanoVna analyzer. Maybe somone has  experience with the Bitx and anayzing his antenna etcetc???
Regards
Rene
Netherlands
_._,_._,_

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shyamhegde
 

Nano VNA is a nice tool to learn and build antennas. Comes with inbuilt battery that lasts easily for few hours. Bit delicate in build and not rugged for field use, especially if you buy the one that has boards exposed from sides and not having frame. But for a hobbyist and occasional use perfect and value for money.
Check if you see a Nano VNA-F variant which is said to be better than those tiny ones.


Curt
 

Okay now I will tell a story - I first saw and used an automated VNA around 1979.  I will still a EE college student, but had a work assignment at a company then called RCA.  The VNA from a company then called HP was 2 or 3 racks full of boxes, attached to a computer.  It was revolutionary, expensive and quite rare back then.  (I remember the 8409 - this was one generation before that).  They had 2 of them and they kept them busy. 

The crew here can work with Rene to give some things to measure - actually you can start to see the effective of resistors that are not 50 ohms - as well as whatever antennas you have.  Maybe I should examine the complex impedance of my short 160m top loaded vertical, its decently matched as is and I use it on some other bands as well.  The EFHW I have works on every HF-ish band except 60 and 160m. 

enjoy your complex impedance measurements!

73 Curt