[Antennas] Antennas Digest, Vol 79, Issue 2

[George Frederick]

Niel,

Suggest use of a software defined single-port network analyzer, used in
conjunction with a PC, which can quickly & quite accurately display the true
electrical length of your phased array lines & components.  For amateur work
I have found the Array Solutions AIM-4170-series analyzer to be a real gem
in this department.  It is not only one on the market, but I selected it as
having the most bang-for-the-buck and have been more than pleased with it
for the past couple years of heavy use.  Additionally, it can rapidly
perform other complex analysis functions such as plot SWR bandwidth,
bandpass of say a resonant trap, perform spectrum analysis up to 10 mHz
wide, serve as a very precise signal source, etc., etc.  A number of QST
articles have used plots from this device to clarify technical discussions.
The cost of this item is literally 1% of a typical lab-grade instrument, it
is portable and more than accurate enough for serious hobby work.  The
ability to connect it directly at the feed point & near-instantly read and
store the results on a laptop makes it a tremendous asset when working with
antennas and transmission lines in the field.  Hopefully you can locate a
local HAM who has one of these instruments that would be willing to assist
you in your project.

73   George  AF6JT



On Wed, Aug 4, 2010 at 9:00 AM, <antennas-request at mailman.qth.net>wrote:eur

> Send Antennas mailing list submissions to
>        antennas at mailman.qth.net
>
> To subscribe or unsubscribe via the World Wide Web, visit
>        http://mailman.qth.net/mailman/listinfo/antennas
> or, via email, send a message with subject or body 'help' to
>        antennas-request at mailman.qth.net
>
> You can reach the person managing the list at
>        antennas-owner at mailman.qth.net
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Antennas digest..."
>
>
> Today's Topics:
>
>   1. Tuning Phased Array Harness? (Niel - W0VLZ)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Tue, 03 Aug 2010 11:42:06 -0500
> From: Niel - W0VLZ <w0vlz at aggienetwork.com>
> Subject: [Antennas] Tuning Phased Array Harness?
> To: Antennas at mailman.qth.net
> Message-ID: <4C5846DE.5000700 at aggienetwork.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> After good success with a C-Pole vertical I'm now working on a phased 20
> mtr vertical array using two C-Poles ala section 13.3 in Brian Cake's
> "Antenna Designer's Handbook".
>
> Any suggestions for tuning the phasing network prior to attaching it to
> the antenna? The phasing lines include the DPDT switch and the baluns so
> I don't trust just doing a "measure length and cut" based on the
> velocity factor. I have multiple VFs (some unknown) involved. Since I'm
> talking about lengths that are multiples of a quarter wave I thought I'd
> just leave the antenna end open and tune each length for reactance
> equals zero at the transmitter end. But when using my MFJ 259B Antenna
> Analyzer I found that the X=0 point may be several hundred KHz
> wide....not giving an accurate cut length.
>
> Can I use a dip meter coupled to a small loop connected at the
> transmitter end and look for resonance? or does the loop upset the
> measurement?
>
> Should I just not worry about a few inches?
>
> Any other suggestions?
>
> tnx es 73,
> Niel - W0VLZ
> http://www.prismnet.com/~nielw/wa5vlz.htm
>
>
> ------------------------------
>
> ______________________________________________________________
> Antennas mailing list
> Home: http://mailman.qth.net/mailman/listinfo/antennas
> Help: http://mailman.qth.net/mmfaq.html
> Post: mailto:Antennas at mailman.qth.net
>
>
> End of Antennas Digest, Vol 79, Issue 2
> ***************************************
>