[Elecraft] OT: Remote antenna tuner

[W2xj]

Let me add that even a quarter wave vertical is rarely a perfect match. The 50 ohm point is almost never the same as the j0 point. HF broadcasters don’t even try for a match. Typically open wire line is used and the match is achieved at the transmitter output network. They pump up to 500KW into VSWRs over 2:1. 

Sent from my iPad

> On Mar 31, 2019, at 6:03 PM, Fred Jensen <k6dgw at foothill.net> wrote:
> 
> I also disagree.  AM broadcast verticals are designed to achieve a desired pattern and main lobe elevation angle.  Over flat ground, 225 degrees will optimize the ground wave coverage.  However, higher powered stations will then suffer from self-interference at the coverage edges because the sky wave and ground wave interfere.  It's common to shorten the antenna a bit to perhaps 195 degrees or so which tends to reduce the self-interference.  Once the pattern and main lobe angle have been defined, the feed point is matched to the transmission line with an appropriate network.  Neither 225 degrees [5/8 wave] nor 195 degrees are resonant lengths and both require a matching network.
> 
> Many hams do not have the luxury of resonant antennas on every band.  It seems perfectly reasonable to employ some sort of matching network to match the feed point to the coax on bands where it is not resonant AND/OR does not present a 50 ohm load to the coax and needing to do so does not imply there's something wrong with the antenna.
> 
> 73,
> Fred ["Skip"] K6DGW
> Sparks NV DM09dn
> Washoe County
> 
>> On 3/31/2019 9:44 AM, W2xj wrote:
>> I would disagree. Most high power commercial operations use non-resonant mismatched antennas. Typically there is either a tuner at the antenna or open wire is used.
>> 
>> Sent from my iPad
>> 
>>> On Mar 31, 2019, at 12:13 PM, Ken G Kopp <kengkopp at gmail.com> wrote:
>>> 
>>> If an antenna is showing a VSVR of 3:1, something about the situation
>>> is wrong, and most likely it's -not- the antenna.  Fix the problem … feed
>>> the antenna power where it's resonant, assuming the antenna is actually
>>> resonant on the amateur band of interest.  Expecting a tuner to compensate
>>> for a problem external to an antenna is unreasonable, IMO
>>> 
>>> 73!
>>> 
>>> Ken - K0PP
>>> 
> 
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