[R-390] Help with info on a STRANGE SP-600

[William J.Neill]

There's a fourth way, which I used quite a bit when in the US Army 37 
years ago.  It's frequency diversity.  The same traffic is transmitted 
on two different frequencies, thereby minimizing fade.  Works quite 
nicely, especially on long skips.

Bill Neill
Conroe, Texas

On Tuesday, July 20, 2004, at 06:34 PM, Michael Murphy wrote:

> Bob,
>
> Concerning Diversity operation at HF, R390A, SP600 or otherwise, you 
> have
> the right idea. Using two different types of antennas should work OK.
>
> There are three ways to use Diversity at HF.
>
> 1. Simple Space Diversity - Here we need two identical antennas, that 
> is the
> same polarization, gain, and arrival angle. These could be a couple of
> dipoles at 100 feet. They should be spaced out several wavelenths 
> apart (!!)
> however for diversity to really work.
>
> 2. Polarization Diversity - This setup purposely uses two different 
> kinds of
> antennas, like what you were suggesting, a Carolina Windom and an 
> inverted
> L. The antennas should not have drastically different gains, or the 
> system
> will not "vote" properly. Better choices might be a Marconi vertical or
> sloper dipole and a regular dipole.
>
> 3. Arrival angle Diversity - Requires the use of a receiving antenna 
> with
> discrimination in the vertical plane. For this reason it does not 
> appear to
> be a method that is in common use for HF. With a vertically steerable 
> array
> comprising short vertical monopole or active loops, worthwhile 
> improvements
> are possible by isolating the different ionospheric mode and using them 
> in
> diversity.
>
> This was from a paper
> http://murray.newcastle.edu.au/users/staff/eemf/ELEC351/SProjects/Fitzsummon
> s/elec352.htm
> Composed by:
> Troy Morris
> Jay Fitzsummons
> Tony Parezanovic of Newcastle College
>
> Mike WB2UID
>
> ----- Original Message -----
> From: "John KA1XC" <tetrode at comcast.net>
> To: "R-390 reflector" <r-390 at mailman.qth.net>
> Sent: Tuesday, July 20, 2004 11:06 AM
> Subject: Re: [R-390] Help with info on a STRANGE SP-600
>
>
>> Bob,
>>  check out the Hammarlund Historian page (is that Les ?), there's a
>> paragraph about the R-450/FRR-28 towards the bottom.
>> http://www.hammarlund.info/sp600.html
>>
>> BTW looks like removing the ncr from the file name in the 3d link fixed
> it.
>>
>> 73 ,
>> John
>>
>>
>> ----- Original Message -----
>> From: "Rbethman" <rbethman at comcast.net>
>> To: <R-390 at mailman.qth.net>
>> Sent: Tuesday, July 20, 2004 9:46 AM
>> Subject: [R-390] Help with info on a STRANGE SP-600
>>
>>
>>> Fixed the THIRD link.  Have NO bloody idea why it didn't work.
>>>
>>> What's worse - I'm a computer freak!
>>>
>>> Try now.
>>>
>>> Bob
>>>
>>> Gang,
>>>
>>>     I've acquired a "peculiar" Hammarlund SP-600.
>>>
>>>     It is a Model J-11, s/n 9758. [No "X"]
>>>
>>>    Modified by Northern Radio Company for the Diversity Aspects.  NRC
>>> Type 159, Model I, S/N 740.
>>>
>>>    Tagged Receiver, Radio R-450/FRR-28.
>>>
>>>         <http://home.comcast.net/~rbethman/sp600j11front.JPG>
>>>         <http://home.comcast.net/~rbethman/sp600j11rear.jpg>
>>>         <http://home.comcast.net/~rbethman/sp600j11data.jpg>
>>>         <http://home.comcast.net/~rbethman/sp600j11.jpg>
>>>
>>> Bob - N0DGN
>>
>>
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