YES.
In fact, you can add more.
There are several ways to do this.
One way, the simplest, is to simply place the end insulators about 2' or 3'
up the wire and let the last 2 or 3' of antenna on each side hang straight
down. With this, you can easily bring the antenna in resonance.
Another trick I have used is to insert the wire (on each side) through one
end of two insulators, spaced about 5' apart. Tie a 5' rope between the two
insulators, and then pull wire from each direction through, causing the wire
to hang in a semi-circle under the plane of the rest of the antenna. You
can add a couple of feet this way.
As a quick and dirty, just leave the insulators where they are and solder 2
more feet of wire to each end and let it hang straight down. You may need
to tie weights to the ends to prevent them from blowing too much in the
wind. This will bring your resonance down into the 40m band.
73
Rick
-----Original Message-----
From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
On Behalf Of tom stewart
Sent: Tuesday, February 15, 2011 7:17 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Antenna follow up- asked for help in January- need
more help.....
I apologize for not being more clear about my observations. When Isay "dips"
I mean as measured with my antenna analyser directly at feedline- no tuner
involved.
I have about a foot folded over at the end of the legs. I think I can make
room to add 6 inches both ends. Is that worth while?
thanks
Tom
On Tue, Feb 15, 2011 at 2:32 PM, Rick - NJ0IP / DJ0IP <Rick@dj0ip.de> wrote:
> I haven't seen Tom's writing on this, Steve. I will read it. Thanks.
> You can't argue with his point.
> If the tuner is arcing across the C's, then the SWR is probably jumping
all
> over the place too.
>
> The 974 is robust enough that it usually does not arc when running 100w.
> If it does, I immediately add 1/8 wavelength feedline to the feedline for
> the band that is arcing.
> It always cures the problem.
>
> At 100w level, I have found that the MFJ tuner can match a much broader
> range than the Johnson Viking (275w) Matchbox. The Johnson starts arcing,
> yet the MFJ matches the antenna and does not arc.
> At Field Day, our club used to use the Viking for years.
> It has been replaced by the 974 because we don't have to do so much
> feedline
> pruning with it as with the Viking.
> It also has the cross needle SWR bridge and watt meter built in, making it
> convenient.
> I don't know how the efficiency compares at the wild impedance areas, but
> it
> was certainly more convenient and we did not notice any poorer performance
> than in previous years.
>
> 73
> Rick
>
> -----Original Message-----
> From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
> On Behalf Of Steve Hunt
> Sent: Tuesday, February 15, 2011 5:19 PM
> To: Discussion of Ten-Tec Equipment
> Subject: Re: [TenTec] Antenna follow up- asked for help in January- need
> more help.....
>
> Rick,
>
> I you use the T-match simulator at:
> http://fermi.la.asu.edu/w9cf/tuner/tuner.html
> you'll find that minimum tuner loss usually corresponds to minimum
> inductance.
>
> Tom (W8JI) has some interesting views on T-match adjustment. He argues
> that capacitor arcing due to high voltages should be of much much more
> concern than inductor heating and losses. Again, his advice is to use
> the minimum inductance possible. More here:
> http://www.w8ji.com/antenna_tuners.htm
>
> 73,
> Steve G3TXQ
>
> On 15/02/2011 21:43, Rick - NJ0IP / DJ0IP wrote:
> > Gerry, this is what MFJ states in its manual:
> >
> > "Maximum tuner efficiency is achieved with the most capacitance
(settings
> > closest to 0) and the least possible
> > inductance (higher letters of the alphabet). This efficiency translates
> into
> > best power handling, broadest
> > bandwidth, and least power loss. The goal is always to operate the tuner
> at
> > the lowest Q for the LC
> > (inductance/capacitance) circuit."
> >
> > I was a bit confused about the antenna matching well at 7.025 but dips
at
> > 7.500.
> > You should get it to dip at any frequency, but of course you might get
> some
> > dips better than others.
> > The problem is, the C's do not have a vernier, so it is sometimes REAL
> > sensitive when tuning.
> > That's why I put larger knobs on mine. Made it easier to fine-tune.
> >
> > Rick
> >
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--
"No matter how fast you miss, you still lose."
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