[Elecraft] OT:. G5RV's

[Phil Wheeler]

Alas, the poor G5RV.  Now that its been flogged to 
death, maybe we need a new target -- say the Windom?

Phil W7OX

On 8/4/16 10:22 PM, Wes Stewart wrote:
> The tuner loss also depends on how it is 
> adjusted. For example the very popular high-pass 
> Tee with three adjustable elements has an 
> infinite number of possible combinations that 
> will effect a match on the same load Z.  One of 
> them is the lowest loss solution, all of the 
> others aren't.
>
> As I said earlier, in a letter to Dean Straw 
> dated February 2, 1994 I offered an example 
> where the SPC tuner, then current in the 
> handbooks, could be used to match an impedance 
> of 4.34 +j46 to 50 ohm. (I forget where this 
> came from but it was a real possibility)  I 
> assumed Qc = 1000 and Ql = 300 (generous). I 
> used Touchstone to calculate the minimum loss 
> and maximum loss solutions The best case was 1.6 
> dB and the worst case was 7.8 dB.
>
> With lower Q components, Qc = 500, Ql =200, the 
> losses were 2.4 to 9.5 dB!
>
> Wes  N7WS
>
>
>  On 8/4/2016 2:00 PM, Alan Bloom wrote:
>> > It's a pity that too many newcomers, as well 
>> as many oldsters, are
>> > enamored by this piece of wire.
>>
>> The G4RV is definitely a compromise antenna.  
>> However its advantage is that is has low-enough 
>> SWR to be easily matched by most tuners on a 
>> number of bands.
>>
>> > ... the horrific losses that could be 
>> incurred even
>> > with high quality tuners,
>>
>> It's true that tuner losses are the 
>> manufacturers' dirty little secret. Loss is 
>> rarely specified, partly because it can be 
>> pretty bad, and partly because it is hard to 
>> measure, but also because it is not constant - 
>> it depends on the particular impedance being 
>> matched.
>>
>> One exception is the old Drake tuners.  Their 
>> Pi-L topology makes the loss almost independent 
>> of the load impedance.  If you can get it to 
>> match, you know that almost all the power is 
>> going into the feed line. For example, the 
>> MN-2700 that I designed when I was at Drake was 
>> specified at 0.5 dB maximum insertion loss and 
>> I did a lot of testing and tweaking to achieve 
>> that on all bands.
>>
>> Alan N1AL