On Mon, Mar 8, 2021 at 04:58 PM, KG2RG wrote:

Doug, is this the one you have, is this a sufficient model?

PS - the NanoVNA-F is about 4 times this size of the 2.8 inch model, and 4 times as heavy (BIG battery).? It might not fit into a shirt pocket, like the 2.8 will do easily.
?
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Doug, K8RFT

On Mon, Mar 8, 2021 at 04:58 PM, KG2RG wrote:

Doug, is this the one you have, is this a sufficient model?

It is not the one I have. but it should be sufficient.? Aursinc? has sold many, from what I have read online.
The originator and "official" maker is Deepelec.? The Deepelec might be best if you need much support.? The Aursinc does have? good rating on Amazon, though - a good sign.
They are all very similar - it's an "open source" design.? Some manufacturers may cut corners and use cheaper parts, but there's no way to tell.? My original unit was new back when the nanovna had only been availble for 3 or 4 months, and is a cheap knockoff - for example, better ones have metal shielding over some components, but mine does not.? But it still works fine!
If you can afford it, I would recommend a Deepelec NanoVNA-F.? It has a larger 4.3 inch screen, with a TFT display that is FAR easier to read in the bright light outdoors.? I bought it because I just couldn't read the screen of the older 2.8 inch model when adjusting tuning coils on my Butternut HF6V.? There's a very active nanovna group on groups.io (like this group), and another for the -F model (but the -F group is a lot smaller and less busy).?? Both models work the same, but use different processors & firmware.? The -F also has more memory and can store data readings.? All types can be connected by USB to a PC, and there are several PC programs that add more functionality - but not portability.
If you get one, you WILL have questions and need support.? Since they're "open source" and cheap, there is not much documentation or printed help.? But there is a LOT of info and help on the internet.? Watch some nanovna videos on youtube.? They might help you to decide.
?The Nanovna can also measure/test filters, coils, tuned circuits and other "stuff".?
If you like to build antennas, you really should have one.? But don't forget - it can be quite hard to read outdoors, which is a shame because it's so small and portable.
I got my Nanovna-F last summer from a "ham radio store" seller on AliExpress, but I've forgotten their name.? It was just under $90 then, but took about 3 weeks to get here.
Being able to do an SWR "sweep" of a whole ham band, or the whole HF range, is pretty handy - and you can check the SWR at any frequency in the sweep.
It's an amazing tool!
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Doug, K8RFT

开云体育

I didn’t know it would work below 11.8!

Does anyone know what the lowest battery voltage can be for operation.
My unit shuts off at 11.0 volts.
Is this normal?

So you all got me curious about these unun 1:9 antennas. ?Looked at a few videos and took account the warnings. ?I felt like the transformer design is like the ghost buster “never cross the beams” (windings)... I have some color coded flat ribbon cable... ?I have 50-61 cores, so I started winding the core and discovered the last winding (number 9) was tight and a little over lapping... so I continued anyway.... ?color coded wire makes it a meter less assembly.... ?To cut the chase I checked the SWR from 3-30 mhz and found it kept a 1.0 - 1.2 SWR across the 27mhz... ?the resistor I used for the test was 510 ohms...?
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Tom
AE5NF

On Fri, Mar 5, 2021 at 10:19 AM, KG2RG wrote:

building antennas and matching networks requires the ability to collect data on positive and negative reactance

I suggest you consider getting a NanoVNA.? They are cheap, starting at about $50.? For outdoor use, the NanoVNA-F has a different type of screen that is much easier to read in bright light, and the screen is larger than the cheaper model.
There is a very active Groups.IO for the nanovna's too.? And 'tons' of Youtube videos.
They are designed for antenna analysis, give SWR, reactance (positive & negative/inductive & capacitive), impedance and smith chart displays, and more.? You can set sweep start and stop frequencies and it draws a graph on the screen. Very, very handy and convenient.
?
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Doug, K8RFT

Brian, that is also true with the Sotobeam mast I am using as well. Also, the last section at the top is so small in diameter and so flexible that I simply do not use it in fear that it will not support the antenna and possibly damage that section.?

I just built a 20m half square with some extra wire I had laying around here. It’s 14 gage stranded copper, a little thicker in diameter and heavier than I would normally use for light weight QRP, but it will provide a wider band width up and down from the resonant frequency. If a buy a second Sotobeam mast, even if the sag brings it down to 17ft, the 1/4 wavelength vertices that hang down from the 1/2 wavelength phasing wire are about 16’ and still above ground. The half sq is made to operates at low elevation for optimized performance and low angles of radiation, making this a Lowe hung array that is great for DX. ?However, the coax from the feedpoind does need to remain elivate around the same hight as the feed point for 10ft or so. Just dropping down the feed line vertically next to one of the 1/4 wave verticals may cause some negative results and through things off. So crap, maybe a 3rd mast is needed unless you can find a tre or come other suitable support to keep the feed line elevated out far enough before allowing it to descend down to the transceiver. But this is ham radio and all of the work and experimenting is fun, right? I think. Hi hi

Another option that is slightly heavier and about longer collapsed are the carp fishing poles. The advantage with them is you can hang a light weight antenna about 20 ft in the air. (They extend to 25-30 ft but will bend over with the weight of the antenna so it ends up about 20 ft off the ground).

Brian
K0FBS



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Brian
K0FBS

Dan, here is the link for the one I have that is super light, 300 grams and compacts down to a small 18” packable size.

There are many other portable mast that are longer, stronger and heavier but very good for portable applications in the field where transporting it by foot is not an issue. This one just seems to appeal to me for my needs.?

Thanks for making this post.? Can you post a link for the 19’ carbon fiber mast 18telescoping sections, weighs 300 grams and packs at 18””?

Thanks & 73
Dan
WD4IRK

Sourcing Out parts is a commonly used term meaning to locate a particular part. Example: ?an auto repair shop is sourcing out parts for a customers vehicle. Probably not used in ham radio, so please forgive my poor grammar skills, hi hi

I think I will need a capacitor from 500v to 1kv.?

note: I have not made many other transformers other then a 1:1, 2:2 and 4:1. I always seemed to get a headache when trying to figure out complicated impedance on the Smith chart and never had much testing equipment when I was younger and active in radio ?building antennas and matching networks requires the ability to collect data on positive and negative reactance and some degree of how to calculate the amount of capacitance for example to reduce it down and in or down and out on the chart by finding the values of capacitance needed and putting them either in series or parallel to get to the center on the smith chart. See, I’m getting a headache just thinking about this, hi hi ?

Anyway, it’s been many years of absenteeism some ham radio and I will need accurate building plans and proper parts for any transformers I decide to make, because I’m working half blind without proper test equipment.

?

One can make a 4:1 balun for example, you might be able to measure the impedance to test if your transformer is making the proper impedance transformation, but how does one test for common currents without a tracking generator to sweep the frequencies you plan to operate on. We need a min common current I3 attenuation of 20db for safe and compliant operation. There is also a 4db correction to factor in on a 4:1 balun. so the measurement on the tracking generator needs to see a min of 24db of the I3 common current attenuation. You may get 45db of I3 attenuation at 29Mhz, 25db (correction factor 4db) at 7Mhz and 12db (correction factor 4db) of a full sweep across the entire HF spectrum. In that case, the 4:1 transformer is only good for 7Mhz to 30Mhz.?
if one want to use it on 160m and 80m, then one will need to build a 1:1 and add it in with the 4:1 balun like so: (radio-50Ohm coax-1:1 balun-4:1 balun-ant)

I bought a commercially manufactured 1:1 balun years ago and could not get the SWR under 3:1 on 30Mhz and it was even higher on 50Mhz ?it did get better down around 80m. Turns out that the wire used on the toroid was not 100Ohms ?so I was not getting 50Ohms out the far end of the 1:1. Also, the ?balun was rated for for 1500w but there was no data on the voltage rating of the wire used. after that experience, I stated making my own by sourcing out toroidals and wire with the proper frequency range, Ohms and voltage rating needed.

again, I’m just getting back into the hobby after a decade and a lot of this information is somewhat vague, so please forgive me if any of my information is incorrect. I’m also only running on 6 sips of my 76 sips required optimal operating dosage of caffeinated coffee this morning.

I’m also trying to get my CW speed back up. It’s just unbelievable how so much is lost. But I’m trying, it will take some time.

KG2RG?

?

On Thu, Mar 4, 2021 at 09:35 AM, KG2RG wrote:

I just need to source a 100pf capacitor at 1kv.

(Grammar note:? a "source" is where something comes _from_; to source means to supply.? Like a "water source", or "source of my joy".)

From what I've read about these antennas, you only need the capacitor for the upper 1 or 2 bands.? And with the 5 watt X5105, the capacitor won't likely need to be 1 kV.

I bought this wire from Amazon last summer, and it's very nice, very thin and very limp.

Price:

$14.98 & FREE Returns

?

I made a "random counterpoise" wire for use with the X5105, but have not tried it yet.? And I used some to make a 19 inch counterpoise for my UV5R 2-meter HT, and the wire works very well for the HT counterpoise.
I checked its diameter myself, and the Amazon description is right - 1.2 mm.? Really thin.? I have even thinner enameled magnet wire, but it's stiff, gets tangled and kinked.
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Doug, K8RFT

I found these two references helpful when deciding the length of my end fed antenna installed as a vertical.





73
Joe K9SZ

KG2RG

I believe typical impedance for an endfed halfway is 1500-5000 ohms.? A 49:1 transformer is simple to make,, I use a type 43 torroid and 67 feet of wire.? ?It's resonant 40/20/15 and 10.? I've tuned on 30 and it can be tuned on 80 too but I'm sure the losses are crazy, even though I have made cw and js8 contacts on both.? ?Its simple and easy with just a single wire and no traps needed.? ?I've never tried to load 6m before so I can't give any account for that.? ?A 9:1 transformer would work well with the x5105 too.? I believe that 59' is listed as a good lengtb of wire for 160-6m with a tuner.? ?I'm sure the x5105 tuner would handle 80m-6m easily.? Good luck!??
?
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73
Tim
KF7VUT

Doug,?
A super light weight random wire is my next project. I have those tiny ft50-61 toroidals (super small) and some 28 gage enameled magnetic copper wire. I just need to source a 100pf capacitor at 1kv. I’m still crying about the closure of radio shack.?

anyway, I’ll make some traps and make it for 6m, 10m, 20m and 40m. I’ve never made one before so hopefully it goes well. Not sure when I will start this project with all of the other projects going on, but at least after I get the caps in hand.?

Brian -
There are some very interesting, very small amps on AliExpress, available in different levels of completion (as kits, or assembled, with or without case).
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Doug, K8RFT

Random (NON-resonant) antennas are typically around 400 - 600 ohms and would use a 9:1 transformer.
Resonant end-fed wires tend to be in the 3,000 - 5,000 ohms range, and call for a 49:1 or 64:1 transformer.
There is a LOT of web pages about both types, including lists of lengths that are not resonant on any band.

And apparently, based on the online "literature", the higher the antenna's impedance, the less the need for a counterpoise wire.? Another good subject for reading and investigation.

End-fed sounds very convenient for portable, so you can connect one end to the radio and just throw the other up into a tree.
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Doug, K8RFT

Bob,

I am in agreement with you on the difference between 75 & 100 watts. I also agree that an amplifier for a QRP radio should be for getting a little more power when 5 watts is just not enough. I am looking at getting one for my X5105. However I am not looking for more than 50 watts output. Portability and lower amp consumption are what is most important to me for use with a QRP radio.?
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Brian
K0FBS