[Top] [All Lists]

Re: [TowerTalk] Was "43ft Vertical Feeding Question and Balun Type"

To: Richards <>
Subject: Re: [TowerTalk] Was "43ft Vertical Feeding Question and Balun Type"
From: jimlux <>
Date: Sun, 23 Nov 2008 17:24:48 -0800
List-post: <">>
Richards wrote:
> -- 1 --
> Good question.    My target price would be around $1 G. 
> That is my current threshold for economic pain on this item.

Considering the SGC tuner for 500W is more than $1K, you're basically 
out of luck.  That's a mass production device so the sell price is 
pretty close to the cost of building/selling (i.e. there's not much 
non-recurring-engineering built into the price any more, and they've 
already done all the tooling for manufacture)

> If costing more, I would probably think about it awhile, or just
> stick to what I have now;  but less than that would move me
> to purchase immediately.
> AND while we are considering marketing factors, I would not
> want a single band solution I have to manually change or fiddle
> with to change bands.   I purposely selected this antenna so I
> would have a multi band antenna.   I do not mind having to retune
> it when changing bands, but I would not want to have to go outside
> and fiddle with it to do so in the Michigan Winter.

That's the sort of bandswitch selection scheme outlined earlier in the 
thread. I think, though, that the cost to implement the bandswitch 
scheme isn't going to be a whole lot less than to implement a full up 
autotuner. (assuming one has the intellectual property for the autotuner 
design.. it matters not whether the tuner is tuning 1 watt or 1000, the 
microcontroller algorithm is the same, and that algorithm is the heart 
of the autotuner.. the basic  L and C switching topology is nothing 

> -- 2 --
> Your notion of a remote power amp at the base of the antenna
> is intriguing and especially solves the problem of high energy
> on the coax cable.   One of the problems with these verticals
> when tuned in the shack is high SWR and high energy on the
> coax cable.   Remoting the PA  -and- the tuner (matching
> unit) at the base of the antenna might solve multiple problems.

It's an approach that hasn't seen much use in the ham world for a few 
1) hams have used manually tuned tube PAs for a long time. It's a 
familiar operational concept, and inexpensive to manufacture.  But that 
pretty much means you need to have the amp at the operating position.
2) hams, as a market class, appear to like equipment with many knobs and 
switches and displays, so that's what manufacturers build.  Even the PAs 
with automatic tuning and/or motorized tuning components do this. 
(although, take a look at pictures of W1AW's racks of PAs... those are 
all remotely operated)
3) The operating environment in the shack is a lot more benign than some 
box out at the antenna. Building something to tolerate -20C to 50C is a 
lot tougher than running at room temperature.
4) remote operating needs more automated monitoring (if it starts to 
smell hot from overheating or you hear it crackling and arcing, you're 
right there to turn it off.. if it's a couple hundred feet away in a 
box, it might be the sound of fire engines summoned by your neighbors 
that tells you that things have gone horribly wrong.. )

Ultimately, I guess, the PA on the desk is cheaper. It's not a matter of 
technology or feasibility: pretty much every radio station in the world 
for the last 50 years uses remote control of the power amp in some 
sense. Heck, here in Los Angeles, the transmitters are up on a 5000 foot 
mountain and the control operator is sitting back in a comfortable 
studio 10-15 miles away. (they also DO pay quite a bit for that level of 
reliability and remote operation)

But.. no tune reliable solid state amps are changing this.. The 
environmental issues can be solved (at a price).. there are little 
airconditioner/heaters that install in the side of a Hoffmann enclosure, 

> You may be on to something here...!
> ===============  Richards - K8JHR  ===============
> jimlux wrote:
>> How much would you be willing to pay for this?

TowerTalk mailing list

<Prev in Thread] Current Thread [Next in Thread>