I use an Array Solutions AIM 2180 so far for aligning duplexers, bandpass
filters, determining phasing tranmission line lengths and checking transmission
lines via TDR. All these tools get the classic VNA into a small package with
mobility at much less than cost the classic lab VNA. AIM 2180 isn't the lowest
priced unit of the group and on battery power exhausts a 12 volt pack of AA
cells within 2 hours. These tools do get advanced tools on the ham bench and
save a bunch of time.
Paul - W2NMI
----- Original Message -----
From: Wes Stewart <wes_n7ws@triconet.org>
To: Tower Talk <towertalk@contesting.com>
Sent: Wed, 05 Dec 2018 10:21:45 -0500 (EST)
Subject: [TowerTalk] Antenna Analyzers
A recent post about a new toy led to some discussion about readily available
antenna analyzers that meet the special needs of Topband aficionados who have
to
cope with big BC band signals affecting their measurements.
I mentioned several that I had on hand at the time and another about to arrive.
The new one is here and a quick measurement on my 160 inverted-L in the
presence
of a 1550 kHz 50KW station 5 miles away is positive. Here is a short overview
of the different units.
All of these have some things in common. They can all be "calibrated" using
Open, Short and Load (OSL) standards. This provides the opportunity to
calibrate at the end of a cable or in another connector series. They all
display
data in multiple formats and offer some form of data storage.
1) The N2PK by Paul Kicaik AFAIK started the whole genre of portable, amateur
built vector analyzers that use PC computing power for data
calculation/presentation. (http://n2pk.com/#TP1) Originally, used a parallel
port interface, later ported to USB. First software ran under DOS. Several
contributors built Windows software. Still an excellent device for Topband
guys, but limited frequency coverage. This is a two-port vector analyzer, so
it
would be good for characterizing phasing lines, feed networks and filters as
well as antenna impedances.
2) Short of an HP-8510, 8753 or 3577 the gold standard for hobbyist use IMHO is
the SDR-Kits, DG8SAQ designed VNWA.
(https://www.sdr-kits.net/introducing-DG8SAQ-VNWA3) This is also a two-port
vector analyzer. The VNWA software is *very* powerful, with a commensurate
learning curve, and is well supported by the author Dr.Tom Baier as well as
some
very knowledgeable users. A bit difficult to operate in the field because it's
tethered to a computer, but I have done it. This is a lab grade instrument.
Uses SMA connectors.
3) The Rig Expert line of analyzers are one-port, standalone instruments.
(https://rigexpert.com/) They are well-suited to field work except for some
difficulty reading the screen in sunlight. I have the AA-55 Zoom version.
Data
can be saved internally and read out into their AntScope software via USB. For
further manipulation, s-parameter files can also be read by Zplots. Unit can
also be operated as a test head over USB using AntScope. This is totally
independent of what is on the screen of the instrument. The software version I
have is buggy and adds a bogus data point at the end of the data file. I've
reported this and there is a newer version that might fix this but the colors
chosen for the screen are nearly unreadable and the program structure is a
mystery to me. Uses a "UHF" connector and is powered by two standard AA cells
and/or USB.
4) The FA-VA5 by DG5MK is a very compact standalone instrument with a lot of
features. (https://www.sdr-kits.net/VA5_Page) It is an easily assembled kit.
For field work the screen is very readable in sunlight. Unfortunately, it is
plagued with a horrible interface, just three push buttons. This can also be
used as a one-port test head under the DG8SAQ VNWA software with all of the
attendant power, and complexity. Again, this is totally independent of the
internal calibration, etc. Uses a BNC connector and is powered by two AA cells
and/or USB.
5) The FAA-450 by EU1KY is a work in progress.
(https://bitbucket.org/kuchura/eu1ky_aa_v3/wiki/Home) This one is unique in
that
the standalone interface is a color touchscreen. Originally conceived as a DIY
project it is now offered in various stages of kit or a completely assembled
unit. I purchase the completed unit, which as it turns out is built in China.
The enclosure is a robust, albeit somewhat clunking arrangement of flat plates
keyed with tabs and slots. Firmware is open source. The complete unit comes
ready to use with EU1KY firmware installed. I've installed supposedly more
useful firmware by DH1AKF. I've found a couple of hiccups in this so far, so
the jury is still out. There are a couple of different USB interfaces. With
the correct drivers, the unit can be operated with the Rig Expert AntScope
software. Uses a type N connector and a Li-ion cell, rechargeable over USB.
I'm sure there are others but these are the ones I own and have experience with.
Wes N7WS
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|