[TenTec] Omni VII, Antenna tuning, etc.

[Bob McGraw - K4TAX]

For what ever reason I purchased one of the popular tuners that uses a T 
Match network and one rated at 1.5KW PEP with the intention of using it on 
my 160M and 75M AM station.  There with 350 watts of carrier modulated 100% 
with normal voice modulation, after some time I noticed "smoke coming out of 
the box".  I opened it up to discover the tapped inductor and it's plastic 
structural supports to be stinky gooey brown limp bars.  Fortunately the 
stiffness of the wire held things in reasonable shape.  Although the tuner 
didn't arc or flash-over, as far as a 1.5KW PEP power rating, it isn't. 
{Name omitted to protect the guilty.}

FYI - the mismatch between the input of 50 ohms and the antenna load which 
was 83 ohms +J 35 was not considered excessive.

Be aware that all "legal limit" rated tuners are not equal.

73
Bob, K4TAX


----- Original Message ----- 
From: "Larry DiGioia" <o2 at longwire.com>
To: <kd3jf at arrl.net>; "Discussion of Ten-Tec Equipment" 
<tentec at contesting.com>
Sent: Monday, September 10, 2007 7:03 PM
Subject: Re: [TenTec] Omni VII, Antenna tuning, etc.


> Good tuners, that will work on 80 and 160, will by necessity, consist of
> at least (1) large, expensive, roller inductor, and at least (1) large,
> expensive, variable capacitor.
>
> Really good tuners may even use vacuum-variables, and possibly expensive
> relays and/or band switches.
>
> Even a "1.5KW" rated tuner can go up in flames, with only a few hundred
> watts to a bad mismatch, if you aren't careful...
>
> You aren't going to find even the bare parts for such a tuner for much
> under $300.
>
> If it were possible to substitute or miniaturize these parts and get the
> same performance, there would be no market for the Palstar and other
> fine tuners.
>
> For more, see   http://www.palstar.com/
>
> Larry  N8KU
>
>
> Paul Gates, KD3JF wrote:
>> For what it is worth... I am usually concerned about the cost of things. 
>> If I have to pay $300.00 for a tuner I am going to get one good for 3KW.
>>
>> Ernie Piche N1SW <n1sw at cox.net> wrote: John Huggins wrote:
>>
>>> Ladies and Gentlemen,
>>>
>>> Say I obtain the Omni VII radio and make good use of its Ethernet
>>> control with OMNIVIIOnePlug program (and let's assume this works).
>>>
>>> For total automation of the station, should I rely on the internal
>>> antenna matcher or offload this task to an external automatic matcher?
>>>
>>> In other words, should the extra $300 be spent on the internal matcher
>>> or applied to other, perhaps more appropriate, matching gear?
>>>
>>> There are a lot of correct ways to to this of course, but the opinions
>>> of those with experience are helpful.
>>>
>>> Thanks for any input.
>>>
>>> John
>>> KX4O
>>> _______________________________________________
>>> TenTec mailing list
>>> TenTec at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/tentec
>>>
>>>
>>>
>> Seems to me that if your are going to add an external  tuner then you
>> will have to have a way to tune it remotely.  With the built in tuner
>> the access will be through the One Plug GUI or if your antennas are well
>> matched you won't need a tuner anyway.  Yes the remote operation does
>> work I have been running my rig from my laptop, although only from
>> within my own house, I think they would frown on me working DX from
>> work.  Hi Hi!
>>
>> Ernie
>> N1SW
>>
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>>
>
>
> -- 
> Larry  N8KU
>
> l o n g w i r e . c o m
> HF - DX - CW - Digital
>
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