[Orion] Re: [TenTec] Orion

[Duane A Calvin]

Interestingly, I run a G5RV Jr (the 40m version) at a low elevation just
above the roof of my one-story house.  My shack is under one end of it. 
I have run 1 KW into it on occasion, and using the Orion, 705 mic, (Alpha
99 amp and TT 238 tuner), I have had no RFI problems unless I use the
Heil ProSet.  I need to try a couple different rewires on the ProSet
connections yet, but this is certainly an RF-rich environment, yet I have
not seen problems with a similar setup to what you're using, Eric.  (I
also have an HF2V vertical in the back yard, and it also shows no RF
problems when I use it.)

        73,  Duane


On Sat, 11 Dec 2004 04:27:33 -0500 Sinisa Hristov <shristov at ptt.yu>
writes:
> Eric SENSI wrote:
> 
> > I tried several things at the outside too, choke at the base of 
> the antenna,
> > reduce or lengthen the coax cables to avoid to be close of a 
> multiple of a
> > half-wave long, MFJ-915 common mode filter, RF inquiry filter, 
> ferrites
> > around the cables inside the shack... etc ! No way... still that 
> stupid
> > problem.
> 
> 
> It is true that some parts of Orion are not protected
> particularly well against RF currents. These include
> front panel, CPU, DSP, codecs and audio amplifiers.
> 
> However, your choice of antenna is, I believe, the main problem.
> The standard G5RV suffers from strong common mode currents on
> most bands. These currents cannot be suppressed well using chokes
> because of wildly varying impedance levels...
>  
> If you insist on using the wire on all bands,
> then the safe way would be to use the twin lead
> all the way down to the shack (not just some "magic" length),
> and then use a symmetric coupler (a la Johnson Matchbox).
> I have such a setup here and can run 1.5 kW safely.
> 
> 
> 73,
> 
> Sinisa  YT1NT, VE3EA
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> 
> 


--------------------------------------
Duane Calvin, AC5AA
Austin, Texas

http://home.austin.rr.com/ac5aa