Today's Message Index:
----------------------
1. 05:48 AM - Re: antenna analyzer? (merlewagner2)
2. 06:46 AM - Re: antenna analyzer? (Finn Lassen)
3. 07:02 AM - Re: antenna analyzer? (Finn Lassen)
4. 07:31 AM - DDRR as Comm antenna (Finn Lassen)
5. 07:55 AM - Re: Re: antenna analyzer? (Charlie England)
6. 09:52 AM - Re: antenna analyzer? (merlewagner2)
7. 10:41 AM - Re: DDRR as Comm antenna (Robert L. Nuckolls, III)
8. 10:42 AM - Re: Re: antenna analyzer? (Robert L. Nuckolls, III)
9. 11:27 AM - Re: antenna analyzer? (user9253)
10. 11:38 AM - Re: Re: antenna analyzer? (Robert L. Nuckolls, III)
11. 11:40 AM - Re: Re: antenna analyzer? (Robert L. Nuckolls, III)
12. 11:50 AM - Re: antenna analyzer? (merlewagner2)
13. 12:14 PM - Re: Re: antenna analyzer? (Charlie England)
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| Subject: | Re: antenna analyzer? |
For anyone interested in the VNA-
First educate yourself on what to purchase. There are too many clones out there
and you must be very careful in what you purchase. I have 3 different units which
effectively do the same thing but the user interface is different in each.
Go to the VNA user group at https://groups.io/g/nanovna-users and start researching
the info. The WIKI has a TON of information.
Given you purchase the correct unit (the problem is they keep enhancing this on
a weekly basis) you will be extremely happy with the capability and performance.
And even happier with the price.
I just finished installing a NAV antenna on my Tailwind. Foil was used and attached
to the Lexan windshield. I was able to tune the VOR and ILS portions of the
antenna in real-time while watching the SWR for each frequency.
you can check out antennas to the nth degree, components, chokes, torroids, coax
faults, coax length, impedance, etc, etc
Just educate yourself before purchasing.
--------
KC1DNJ
General Radiotelephone
Commercial SEL
A&P
Building scale P51, rebuilding Tailwind W10
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497330#497330
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| Subject: | Re: antenna analyzer? |
Oops. That should be:
The reason I chose 5/32" tubing is that it's nearly 0.5" "wide". 5/32 *
Pi = 0.48". I'm considering it a 0.5" wide strip rolled into a 5/32" tube.
Finn
On 7/15/2020 6:39 PM, Finn Lassen wrote:
>
> The reason I chose 5/32" tubing is that it's nearly 1" "wide". 5/32 *
> 2 * Pi = 0.98". I'm considering it a 1" wide strip rolled into a
> 5/32" tube.
>
> But maybe I'm understanding it wrongly and it's only 5/32" "wide".
>
> Finn
>
> On 7/15/2020 6:00 PM, Charlie England wrote:
>> Stay in touch when you get it; I'd like to know if it proves useful.
>>
>> On the subject of the cockpit antenna: Contact me direct; I'll send
>> you some 1/2" copper foil tape to stick on the canopy. Works even
>> better for the nav side, if you install a nav radio (set up as
>> half-wave instead of quarter wave).
>>
>> Charlie
>>
>> On 7/15/2020 4:36 PM, Finn Lassen wrote:
>>>
>>> I ordered this https://www.ebay.com/itm/283898850600 ten days ago.
>>> Will probably be several weeks before I get it.
>>>
>>> You can get them a lot cheaper, but I wanted one that'll also be
>>> useful checking transponder (and ADS-B) cable and antenna. (1GHz)
>>>
>>> Still haven't given up on the idea of putting VHF comm antenna under
>>> the RV-4 canopy. Other than vertical polarization, ground plane will
>>> probably be the biggest issue (and impedance matching if I can't get
>>> the ground plane right). Got three 12" 5/32"OD brass tubes from
>>> Hobby Lobby. Should give a reasonably wide bandwidth.
>>>
>>> Finn
>>>
>>>
>>> On 7/15/2020 3:38 PM, Charlie England wrote:
>>>> Hi,
>>>>
>>>> I just stumbledupon a mention of vector network analyzers, which
>>>> to my relatively RF-uneducated mind, appear to be more
>>>> sophisticated versions of antenna analyzers.
>>>>
>>>> Any thoughts on purchasing something like this
>>>> nanoVNA
>>>> <https://www.ebay.com/itm/NanoVNA-H-NanoVNA-50-900MHz-Vector-Antenna-Network-Analyzer-VHF-UHF-UV-HF-VNA-/202990079481?_trksid=p2385738.m4383.l4275.c10&var=503177797619>
>>>> instead of a low end analog antenna analyzer? Purchase cost seems
>>>> about the same, and at least some versions seem to allow some trick
>>>> functions that used to be ungodly expensive, like TDR for
>>>> measuringlengths of wire & cable.
>>>>
>>>> My short term personal motive is to get a cheap SWR meter that
>>>> eliminates analog meter movements while possibly having some
>>>> down-the-road uses beyond a once-a-decade SWR check.
>>>>
>>>> Any thoughts from the RF-intelligent brain trust?
>>>>
>>>> Thanks,
>>>>
>>>> Charlie
>>>>
>>>
>>>
>>> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient&utm_term=icon>
>>> Virus-free. www.avast.com
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>>>
>>> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>>
>
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| Subject: | Re: antenna analyzer? |
On 7/15/2020 11:47 PM, Robert L. Nuckolls, III wrote:
> At 04:36 PM 7/15/2020, you wrote:
>
>> I ordered this https://www.ebay.com/itm/283898850600
>> <https://www.ebay.com/itm/283898850600> ten days ago. Will probably
>> be several weeks before I get it.
>>
>> You can get them a lot cheaper, but I wanted one that'll also be
>> useful checking transponder (and ADS-B) cable and antenna. (1GHz)
>>
>> Still haven't given up on the idea of putting VHF comm antenna under
>> the RV-4 canopy. Other than vertical polarization, ground plane will
>> probably be the biggest issue (and impedance matching if I can't get
>> the ground plane right). Got three 12" 5/32"OD brass tubes from
>> Hobby Lobby. Should give a reasonably wide bandwidth.
>>
>> Finn
>
> Check out this article from a 1971 issue of QST Magazine
>
> http://www.aeroelectric.com/articles/Antennas/DDRR_Antenna.PDF
> <http://www.aeroelectric.com/articles/Antennas/DDRR_Antenna.PDF>
>
> A 2 meter (146 Mhz) version of this antenna
> is 6" in diameter and sets about 1" off the
> ground plane. An aviation version would be
> about 7" in diameter.
>
> It's bandwidth is probably pretty narrow . . .
> you'd have to build one and sweep it to
> see if it's usable. Would this fit on
> the deck just behind the rear seat?
>
> I've got one of those analyzers but haven't
> had time to make it sing, dance and do dishes.
> I've been using the VNA Tiny which is a good
> bit more expensive. It seems to work well.
> Let us know how that 'baby' VNA works for you!
>
>
> Bob . . .
>
Thanks Bob.
I did look at this earlier. There's a guy on VansAirforce.com that put
it in a wing tip. Appeared to work for his purpose (APRS Tracking, which
I assume use a single frequency)
https://vansairforce.com/community/showthread.php?t=39797
I dismissed it as being too heavy (and possibly narrow bandwidth), but
didn't consider putting it under the canopy. He used hardware store
copper tubing. But may be able to use some very thin plastic tubing as a
form and wrap copper foil around it. Then there's the tuning capacitor:
variable and high voltage. May be able to replace that with a fixed cap.
Finn
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| Subject: | DDRR as Comm antenna |
http://www.aeroelectric.com/articles/Antennas/DDRR_Antenna.PDF
The article says of the diameter (D) of the tube:
"The larger D is the higher efficiency is".
What is mean by "efficiency"?
If it's Q or how narrowbanded the antenna is, then it's the opposite of
a whip (1/4 wave) antenna where you want larger diameter for a larger
bandwidth (Q).
Or is it somehow the radiation pattern?
https://www.everythingrf.com/community/what-is-antenna-efficiency
What happens to the power not radiated? Goes back to transmitter or
converted into heat in the antenna?
I'm a hopeless novice on antennas.
Finn
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| Subject: | Re: antenna analyzer? |
On 7/16/2020 7:47 AM, merlewagner2 wrote:
>
> For anyone interested in the VNA-
>
> First educate yourself on what to purchase. There are too many clones out there
and you must be very careful in what you purchase. I have 3 different units
which effectively do the same thing but the user interface is different in each.
>
> Go to the VNA user group at https://groups.io/g/nanovna-users and start researching
the info. The WIKI has a TON of information.
>
> Given you purchase the correct unit (the problem is they keep enhancing this
on a weekly basis) you will be extremely happy with the capability and performance.
And even happier with the price.
>
> I just finished installing a NAV antenna on my Tailwind. Foil was used and attached
to the Lexan windshield. I was able to tune the VOR and ILS portions of
the antenna in real-time while watching the SWR for each frequency.
> you can check out antennas to the nth degree, components, chokes, torroids, coax
faults, coax length, impedance, etc, etc
>
> Just educate yourself before purchasing.
>
> --------
> KC1DNJ
> General Radiotelephone
> Commercial SEL
> A&P
> Building scale P51, rebuilding Tailwind W10
That's the kind of info I've been hoping to find (failing someone
telling me to 'buy *this one*). My biggest concern is exactly what
you're describing; I want as dirt-simple a user interface as possible,
and a manual written by an English-as-a-1st-language writer. It's great
to see confirmation of all the other 'value added' features.
If you have a specific recommendation that would get me up and running
for a sub-$100 price point, I'd love to see it.
Do you have a web site detailing your P51 & Tailwind projects?
Thanks,
Charlie
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| Subject: | Re: antenna analyzer? |
[quote="ceengland7(at)gmail.com"]On 7/16/2020 7:47 AM, merlewagner2 wrote:
>
> telling me to 'buy *this one*). My biggest concern is exactly what
> you're describing; I want as dirt-simple a user interface as possible,
> and a manual written by an English-as-a-1st-language writer. It's great
> to see confirmation of all the other 'value added' features.
>
> If you have a specific recommendation that would get me up and running
> for a sub-$100 price point, I'd love to see it.
>
> Do you have a web site detailing your P51 & Tailwind projects?
>
> Thanks,
>
> Charlie
>
> --
> This email has been checked for viruses by Avast antivirus software.
> https://www.avast.com/antivirus
Charlie,
You are asking for a lot these days. I think you must be older than I am.....
OK, for what it's worth - I would purchase from
http://www.randl.com/shop/catalog/product_info.php?products_id=75145
They are an official[?] U.S. distributor of the Hugen version of the NANOVNA and
the link is to the 4" unit. This site also sells a manual for the VNA. They
told me the shipment they just received is the latest version.
For $60 and $14 for the manual (or start reading on the groups link I provided
earlier) you can start doing amazing things.
I understand enough to be dumb but I have managed to get the unit functioning.
You need to understand calibrations, etc but the book will get you started. Again,
go to the groups site and READ the wiki.
Sorry, no web site for my projects. I get really tired of all the "experts" and
their opinions on how airplanes should be built.
Merle
--------
KC1DNJ
General Radiotelephone
Commercial SEL
A&P
Building scale P51, rebuilding Tailwind W10
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497335#497335
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| Subject: | Re: DDRR as Comm antenna |
At 09:28 AM 7/16/2020, you wrote:
><http://www.aeroelectric.com/articles/Antennas/DDRR_Antenna.PDF>http://www.aeroelectric.com/articles/Antennas/DDRR_Antenna.PDF
>
>The article says of the diameter (D) of the tube:
>"The larger D is the higher efficiency is".
>
>What is mean by "efficiency"?
>
>If it's Q or how narrowbanded the antenna is, then it's the opposite
>of a whip (1/4 wave) antenna where you want larger diameter for a
>larger bandwidth (Q).
>
>Or is it somehow the radiation pattern?
>
><https://www.everythingrf.com/community/what-is-antenna-efficiency>https://www.everythingrf.com/community/what-is-antenna-efficiency
>
>[]
>
>
>What happens to the power not radiated? Goes back to transmitter or
>converted into heat in the antenna?
Looking into the antenna's feedline connector, the
observed or measured resistance is mad up of three
components: (1) ohmic resistance, (2) radiation
resistance, and (3) reactance.
Ohmic or metallic resistance is that which emulates
an ordinary resistor . . . when it comes to resistors,
the can do only one thing . . . get warm. I.e. convert
electrical energy into heat. This is the analog to
'dummy loads'; devices that allow you to test a transmitter
while minimizing if not eliminating all radiation.
In antennas, ohmic resistance equates to dissipated
energy.
Radiation resistance is that component of the antenna
that launches energy into the environment. Suppose
your antenna shows 1:1 SWR (no reactance) at 50
ohms but 40 of those ohms are ohmic and only
10 ohms are radiation resistance. Then 80% of
energy at the end of the feedline goes up in heat;
20% gets radiated.
In the 'perfect' antenna, reactance is zero at
resonance and the resistive components add
up to 50 ohms; i.e. 1.0:1 SWR and ohmic resistance
is near zero (impossible dream).
But check out the two comparative plots of an
experimental antenna evaluated with a VNA Tiny
analyzer:
The thin spike antenna is a simple, 1/4 wave
ground plane with no attempt to achieve 50
ohms resistance at the feed point. Note
that SWR never gets down to 1:1 [3] because
it's about +6 ohms (Xs inductive) at resonance.
1.5:1 bandwidth [1]->[2] is 67Mhz
The blade antenna is also 1/4 wave long with
no special attempt at hitting a 50 ohm feedpoint
impedance. This antenna has two swr 'dips' and
a measured 1.5:1 bandwidth of 104Mhz. Here we
see better SWR conditions at two points
where we also see lower reactive components
at [3] and [4].
Tese studies only go to the antenna's
ability to accept energy squirting out the
end of the feedline. It says NOTHING about
efficiency or radiation pattern. But with
simple, 1/4-wave radiators on clear-space
ground planes there is little that needs
to be done in those departments.
If you're interested in pursuing the DDRR
approach, it would be easy to do on your workbench
with a VNA. The antenna is small and easy to
fabricate. You could explore ways to increase
bandwidth.
>I'm a hopeless novice on antennas.
We all were in the beginning . . . No better
way forward than to get out the hammers-n-saws
and MEASURE stuff!
Bob . . .
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| Subject: | Re: antenna analyzer? |
At 07:47 AM 7/16/2020, you wrote:
><wagnermerle@gmail.com>
>
>For anyone interested in the VNA-
>
>First educate yourself on what to purchase. There are too many
>clones out there and you must be very careful in what you purchase.
>I have 3 different units which effectively do the same thing but the
>user interface is different in each.
>
>Go to the VNA user group at https://groups.io/g/nanovna-users and
>start researching the info. The WIKI has a TON of information.
Great data point sir! Thanks.
Bob . . .
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| Subject: | Re: antenna analyzer? |
I have made homemade antennas in the past and wished that I could measure
the resonate frequency. Does the NANO VNA H4 do that? If that is the only
feature that I want, is there a less expensive alternative? This may be wishful
thinking, but is it possible to use a structural part of the airframe as an
antenna? An antenna analyzer could help locate where to attach coax cable.
Of course such an antenna would likely have a skewed radiation pattern.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497338#497338
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| Subject: | Re: antenna analyzer? |
>>
>>
>>Go to the VNA user group at https://groups.io/g/nanovna-users and
>>start researching the info. The WIKI has a TON of information.
>
> Great data point sir! Thanks.
>
> Bob . . .
P.S. I've joined this group and took a quick look around.
Heaven knows I don't need another 'time sink' but at
first blush, this is a gold-mine of VNA-users practical
information.
I strongly encourage joining this group for everyone interested
in adding a VNA to to their toolbox.
Bob . . .
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| Subject: | Re: antenna analyzer? |
At 01:22 PM 7/16/2020, you wrote:
>
>I have made homemade antennas in the past and wished that I could measure
>the resonate frequency. Does the NANO VNA H4 do that? If that is the only
>feature that I want, is there a less expensive alternative? This
>may be wishful
>thinking, but is it possible to use a structural part of the airframe as an
>antenna? An antenna analyzer could help locate where to attach coax cable.
>Of course such an antenna would likely have a skewed radiation pattern.
The VNA is a sweep signal generator teamed up with a
network analyzer in one box. As you can see from
the plots I posted earlier, you can glean a great
deal of information about the radio frequency characteristics
of a host of 'loads'.
I have a nano-VNA that I've yet to exercise but
have found the big brother VNA Tiny to be
a powerful investigative tool.
https://tinyurl.com/ybm5jxlp
Bob . . .
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| Subject: | Re: antenna analyzer? |
user9253 wrote:
> I have made homemade antennas in the past and wished that I could measure
> the resonate frequency. Does the NANO VNA H4 do that? If that is the only
> feature that I want, is there a less expensive alternative? This may be wishful
> thinking, but is it possible to use a structural part of the airframe as an
> antenna? An antenna analyzer could help locate where to attach coax cable.
> Of course such an antenna would likely have a skewed radiation pattern.
The NANOVNA does that and MUCH more. You just have to learn how to use it. Groups
wiki and tons of video via youtube. w2aew has some excellent videos on youtube.
Using the structure as an antenna - not a good plan. Structure is great for a ground
plane.
attaching photo of my NAV/ILS antenna. Used RG174 to feed.
Merle
--------
KC1DNJ
General Radiotelephone
Commercial SEL
A&P
Building scale P51, rebuilding Tailwind W10
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497341#497341
Attachments:
http://forums.matronics.com//files/nav_ils_632.jpg
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| Subject: | Re: antenna analyzer? |
On Thu, Jul 16, 2020 at 12:00 PM merlewagner2 <wagnermerle@gmail.com> wrote:
> wagnermerle@gmail.com>
>
> [quote="ceengland7(at)gmail.com"]On 7/16/2020 7:47 AM, merlewagner2 wrote:
>
>
> >
> > telling me to 'buy *this one*). My biggest concern is exactly what
> > you're describing; I want as dirt-simple a user interface as possible,
> > and a manual written by an English-as-a-1st-language writer. It's great
> > to see confirmation of all the other 'value added' features.
> >
> > If you have a specific recommendation that would get me up and running
> > for a sub-$100 price point, I'd love to see it.
> >
> > Do you have a web site detailing your P51 & Tailwind projects?
> >
> > Thanks,
> >
> > Charlie
> >
> > --
> > This email has been checked for viruses by Avast antivirus software.
> > https://www.avast.com/antivirus
>
>
> Charlie,
>
> You are asking for a lot these days. I think you must be older than I
> am.....
>
> OK, for what it's worth - I would purchase from
>
> http://www.randl.com/shop/catalog/product_info.php?products_id=75145
>
> They are an official[?] U.S. distributor of the Hugen version of the
> NANOVNA and the link is to the 4" unit. This site also sells a manual for
> the VNA. They told me the shipment they just received is the latest
> version.
>
> For $60 and $14 for the manual (or start reading on the groups link I
> provided earlier) you can start doing amazing things.
>
> I understand enough to be dumb but I have managed to get the unit
> functioning. You need to understand calibrations, etc but the book will get
> you started. Again, go to the groups site and READ the wiki.
>
> Sorry, no web site for my projects. I get really tired of all the
> "experts" and their opinions on how airplanes should be built.
>
> Merle
>
> --------
> KC1DNJ
> General Radiotelephone
> Commercial SEL
> A&P
> Building scale P51, rebuilding Tailwind W10
>
>
> That's exactly the kind of recommendation I've been wanting! Hoping to get
one in my hands soon, and I'll begin perusing the VNA group. Having access
to that kind of support group is what I hoped for; an 'RF' group similar to
the support we all get with basic electrical stuff on this list. Many
thanks for both tips.
Congrats on the Tailwind. I've had the pleasure of flying several examples,
and they are truly impressive performers, and at a great price point. If I
could find one with the cockpit room and 'creature comforts' of an RV, I'd
seriously consider trading in my RV-6.
Charlie
(And while I'm not cheap, if I spend a nickel, I expect some change...)
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