[TenTec] Antenna is up, but the coupler doesn't like 160 meters

Mon Oct 14 22:58:09 EDT 2013

Diddling a bit more, the feed point Z of the antenna is projected to be 
around 20 to 25 ohms.  The feed line is about 3/8 wavelength or about 135 
degrees.  I see nothing wrong with these values that might point to an 
issue.

I will presume the feedline is brought away from the antenna at near 90 
degrees and is not running parallel with the antenna.  This could create a 
problem should he feedline be basically parallel with the antenna.

Hopefully you are using a 1:1 current balun and not a 4:1 current or voltage 
balun.  If you are using a 4:1 balun, I suggest turning it around in the 
circuit such that it is operating as a 1:4 balun.  If you are using the 
configuration as a 4:1 balun, with a Z on the output side at some 20 ohms, 
then tuner is seeing something like 5 ohms.  Thus finding the Z to be 
outside of the matching range of the tuner.

Just a few thoughts and ramblings.

73
Bob, K4TAX

----- Original Message ----- 
From: "Bob McGraw - K4TAX" <RMcGraw at Blomand.net>
To: "Discussion of Ten-Tec Equipment" <tentec at contesting.com>
Sent: Monday, October 14, 2013 7:27 PM
Subject: Re: [TenTec] Antenna is up, but the coupler doesn't like 160 meters

> 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 at sssnet.com>
> To: "Discussion of Ten-Tec Equipment" <tentec at 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 at 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
>>> _______________________________________________
>>>
>> _______________________________________________
>> TenTec mailing list
>> TenTec at contesting.com
>> http://lists.contesting.com/mailman/listinfo/tentec
>>
>
>
> _______________________________________________
> TenTec mailing list
> TenTec at contesting.com
> http://lists.contesting.com/mailman/listinfo/tentec
> 