If C is at max this clearly indicates the need for external capacitity.
This can be connected to the terminals on the rear. Typically 1000 pf
should be adequate. I find that necessary on my installation.
73
Bob, K4TAX
----- Original Message -----
From: "Mike Bryce" <prosolar@sssnet.com>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Tuesday, October 15, 2013 10:18 AM
Subject: Re: [TenTec] Antenna is up, but the coupler doesn't like 160 meters
bob,
that's basically how I've been attacking the problem.
set c @2 and L @30
apply some rf and move between HI Z to LO Z.
When I find a spot that will result in a 2:1 swr, the L is still at 30 and
the C max
Move lower in freq and there is no solution.
right now, all I can do is think about it, I'm down in the bed with the
iPad
mike
Mike Bryce, WB8VGE
the heathkit shop
SunLight energy systems
J e e p
o|||||||o
On Oct 14, 2013, at 8:27 PM, Bob McGraw - K4TAX wrote:
Based on these numbers, the antenna should show resonance at about 1.8
MHz and the feedline should show resonance at about 2.75 MHz. Let me
emphasize that these are resonance numbers are not anyway related to SWR
values. With an instrument such as the MFJ 259 analyzer being operated
as a dip meter, you should see a dip at or close to these two
frequencies. Again, disregard any SWR value at this point as it is a
ratio of impedance and has nothing to do with resonant frequency.
If you are using something like a Tentec 238 or 239 tuner, connect the
600 ohm line direct to the tuner terminals and be sure to have the jumper
in place from Single Wire terminal to one terminal of the Balance Line
terminals. Also for 160M you will likely need the 1000 pF cap from the
External Cap terminal to ground. Especially true of the lower SWR/match
takes place with the impedance switch on the low side. This is a true
trial-and-error determination. I've found that 160M antennas are more
problematic in terms of attaining a match than most any other band.
If you have several tuners that will not match the load, then the likely
choice is to change the length of the feedline some + or - 10 ft.
Procedurally with the 239 tuner, set the inductance to maximum value and
the capacitor value to #2. Then switch between the Lo Z #1 and Hi Z #1
positions noting which shows the lower SWR. Alternate adjust the
Capacitor and inductor for the lowest reading. Should the capacitor be
maxed out then switch to the next value.
I do recall that some tuners have a reversed notation in that a capacitor
value of 0 is maximum C while on others a value of 0 is minimum C.
Personally, I looked inside the box to see where maximum C occurs and
maximum L occurs with regard to the scaling and made notes accordingly.
In my case for 160M and the internal balun, the Z switch required
selected values of 3, 4, or 5 depending on frequency while the L value is
about 20 to 24 on the 0 - 30 number scale.
73
Bob, K4TAX
----- Original Message ----- From: "Mike Bryce" <prosolar@sssnet.com>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Monday, October 14, 2013 4:52 PM
Subject: Re: [TenTec] Antenna is up, but the coupler doesn't like 160
meters
Jim,
The antenna is a doublet up 50 feet inverted vee style.
It is feed with about 170 ish feet of 600 ohm open line.
None of the couplers can find a tuning solution
All other bands work fine
Sent from my iPad at Aultman hospital.
Mike wb8vge
On Oct 14, 2013, at 11:09 AM, Jim GM <jim.gmforum@gmail.com> wrote:
Hi Mike, WB8VGE
Hope your surgery goes well for you.
I have gone and still going thru issues with my inverted L on 160M like
your having.
How long is your antenna? Is it a dipole or Folded dipole? I did not
see on your post the answers to these questions.
How high do you have it?
Your going to find or have found that the tuner you have and other
tuners will not work on 160M. They just cannot handle a near 50 ohm
match or less no matter what they claim. All they want is your money.
So you need to add additional matching out side the shack with coils
and homemade capacitors made from coax cable, thats if you have a
limited junk box like I do.
Any ways the external matching will aid your tuner in the shack to take
care of the rest.
It will take some time and it is not a quick fix.
--
Jim K9TF
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