[TenTec] Orion - Work in Progress - Part 1

[N0KHQ at aol.com]

Skip I understand you frustration with the Orion.
My frustration with SDR's began with the purchase of the Jupiter about 3  
years ago.
 
I know you probably don't want to hear this, but, these rigs are very  
susceptible to RFI. If there is any...and I mean any, stray RF in your shack the  
Orion or the Jupiter will find it.
 
First off, the Orion, like the Jupiter, is nothing more than a computer in  
an RF environment inside a transceiver case.
 
Special RF Grounding and Power Supply precautions must be taken in  order for 
the Orion or Jupiter to perform without incident. I know what  your going to 
say, "hey, I never had any problems with my other rigs". Well,  your other 
rigs were not SDR's.
 
A lot of hams have jumped into the SDR arena without thinking, like  myself, 
about what they were getting themselves into. SDR's are the next step in  the 
evolution of ham radio transceivers. By the peak of the next solar cycle you  
will see one of the other leading manufacturers of ham radio  transceivers 
come out with an SDR. It could be Icom, they are in the early  stages with the 
introduction of the IC-7800.
 
All of the top rigs out today, TS-870, TS-950SDX, FT9000DX,  IC-7800 and so 
on will be referred to as "Boat Anchors", just like we refer  to the tube type 
rigs of yesterday as "Boat Anchors". I know all of these  rigs work great, but 
there is a time when a product must evolve to the  next step. And, SDR's are 
the next evolutionary step in Amateur  Radio. Whether you, I, or anyone else 
likes it or  not......its coming.
 
If your dead set on getting rid of the Orion, don't waste your time reading  
any further. However, if your willing to give it one more shot......keep  
reading.
 
Firstly, when you hear or read about an Orion owner praising the operation  
of their rig, they are not trying to blow smoke up your butt. It's true,  the 
Orion is a great rig, and in my opinion, the best rig on the market today in  
any price range.
 
So, here we go! Please follow these instruction exactly.
 
1. If your running a balanced antenna, purchase a 1:1 50ohm Bal to 50ohm  
Unbal current balun from Radio Works (B1-2K) and install it at the antenna  feed 
point. This balun will prevent antenna currents from coming down the shield  
of the coax and entering you station and at the same time allow for a graceful  
transition from a balanced system to an unbalanced system.
 
2. If your running an unbalanced antenna, purchase an RF Balun kit from  
Polomar-Engineering and install it at the antenna feed point. For reasons  above.
 
3. Purchase from Radio Works a T-4 Line Isolator. This isolator will  install 
right at the back of the coax connector/s on the Orion. This is a  must do.
 
4. The power for your Orion, I assume, is coming from a DC Power  Supply that 
is plugged into a 115vac circuit. This circuit should be a dedicated  circuit 
and not shared with other appliances in your home. Appliances in your  home, 
depending on their load impedance's are dumping reactive currents onto  your 
service neutrals and grounds. The currents are in the milliamp range and  could 
create havoc in your power supply depending on how well your power supply  is 
capable of filtering the incoming AC.
 
5. What I do is, the DC power cable going from the power supply to the  Orion 
is wrapped around a 2-1/2" toriod donut, 6 turns one direction and 6 turns  
the opposite and other direction. 
 
6. One of the biggest culprits is the Orion amplifier keying line. This  line 
should be wrapped around one of those 3/4" x 3/4" x 1-1/4" toriod cubes as  
many times as possible. RS sells them.
 
7. Now heres a subject that you may or may not have a problem with: RF  
Grounding.
 
Some hams get a little confused when talking about Grounding for RF and  
Grounding for Lightning protection. They are not the same and should be  addressed 
separately. Grounding for Lightning protection will do very little for  RF 
grounding. But Grounding for RF will help with Lightning  protection.
 
Most ham radio books illustrate a typical station grounding system, where  
you have this big copper plate or bar behind your station and every piece of  
your equipment is supposed to be grounded to this bar and then a wire runs from  
this bar outdoors to a grounding rod. This illustration is 100% totally wrong 
 and does result in the biggest ground loop in the history of Amateur  Radio.
 
See Part 2 for continuation.
 

 

73
John / N0KHQ / St. Louis

Always on  18.130

Antennas:

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_http://www.hamuniverse.com/antennas.html_ (http://www.hamuniverse.com/) 
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