If you have a quater wave vertical resonating on 1,9 Mhz, the swr 1:2 bandwith
will be > 200 kHz.
Even if your feedline has 3 dB attenuation (that is a lot on this band), the
additional loss will be 0,33 dB.
Nothing to worry about, and not at all a reason to use a tuner at the base of
the antenna.
If your TX has troubles to give its power correct to the cable, use a tuner in
the shack.
73, Kees PE5T
Verzonden vanuit Mail voor Windows 10
Van: fmoeves
Verzonden: vrijdag 15 mei 2020 19:20
Aan: topband@contesting.com
Onderwerp: Re: Topband: 160m Vertical
Tree, Thank you very good idea. One more reason to hang out here. I used the
Harpin match as Jay mentioned on my inverted L worked great. 73 Fred KB4QZH
-------- Original message --------From: Tree <tree@kkn.net> Date: 5/15/20
11:34 AM (GMT-05:00) To: Frank Donovan <donovanf@starpower.net> Cc: 160
<topband@contesting.com> Subject: Re: Topband: 160m Vertical One approach for
the inductor that I have used when doing parasitic elementtuning is to put two
SO239's in series and either put a shorted plug in forno added inductance - or
a PL259 fashioned with a few turns of heavy gaugewire. You can label them for
the frequency you are wanting.I used that technique to go from a director to a
reflector back when I wasplaying with a vertical parasitic array on 160.Tree
N6TROn Fri, May 15, 2020 at 8:28 AM <donovanf@starpower.net> wrote:>> Hi
Ron,>>>> A more reliable approach is a tuner in your shack. The extra coax>
cable loss from elevated VSWR is insignificant on topband.>>> How high up the
band do you want to go and at what maximum VSWR?>>> A resonant Rohn 25 160M
vertical will be about 124 feet tall for> resonance around 1820 kHz>> If for
some reason you must install a tuner at the feed point of the> vertical, follow
Tree's advice and make it slightly short: 120 feet> of 115 ft if you need to
tune for minimum VSWR above 1900 kHz.>>>> Use a small tapped inductor to tune
it around the band.>>> 73> Frank> W3LPL>>>>>> ----- Original Message ----->>
From: "Tree" <tree@kkn.net>> To: "Ron WV4P" <wv4ptn@gmail.com>> Cc: "160"
<topband@contesting.com>> Sent: Friday, May 15, 2020 3:18:39 PM> Subject: Re:
Topband: 160m Vertical>> Slightly shorter makes it easy to use an inductor to
make up the> difference. If you make it long - you can do the same with a
capacitor -> but it's typically more trouble than the inductor.>> Tree N6TR>>
On Fri, May 15, 2020 at 8:15 AM Ron WV4P <wv4ptn@gmail.com> wrote:>> > I have
built an insulated base for a 1/4 wave 160 antenna. The antenna> > will be XXX'
of Rohn 25. In searching I see people using heights from> 115'> > - 130' with a
pretty high number around 124'.> > I do not know how I am going to match it
yet, I figure I will do my> > research on that once it's up so I can learn
while experimenting.... But> > the height has me second guessing. I want it
tunable across the band,> > perhaps using a Tornado Tuner like my JK 801's have
with a motorized> > inductor ? But the question at hand is do I want the
antenna Tall or> Short> > ? What is the Method behind the Madness ? :o)> >> >
Thanks in advance,> > Ron WV4P> > _________________> > Searchable Archives:
http://www.contesting.com/_topband - Topband> > Reflector> >>
_________________> Searchable Archives: http://www.contesting.com/_topband -
Topband> Reflector>> _________________> Searchable Archives:
http://www.contesting.com/_topband - Topband>
Reflector>_________________Searchable Archives:
http://www.contesting.com/_topband - Topband Reflector
_________________
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
_________________
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
|