[R-390] “A” and SP 600 Heretic check-in

[Bob kb8tq]

Hi

Well, the “gotcha” is that the alternative is no longer a $9,000+ super duper box. There are a lot
of sub $300 SDR alternatives out there. Locked to something good (an Rb or a GPSDO) they
are way better than any of the “old stuff”. Selectivity wise … yup … Dynamic range … gulp …
take a look at the numbers. Sensitivity keeps getting better. If you live on planet Earth with normal 
noise levels and antennas, not much wrong with SDR sensitivity wise. Want to demodulate this or
that weird signal? … not a problem.  Something new comes out next week? Download new software.
Price wise, less money than an R-390 on eBay. Yes, you will do a bit of this and that. You also will
poke a bit at than 390 ….

Now, I’m not trying to sell anybody a SDR board or get them to toss out their R-390. Far from it actually.
One is very much not the same as the other. Both are projects, they have different ends and stops on the way. 
I’m just pointing out that there has been a lot of change in how you do a radio, even in the last 
decade or so. If you are going to decide “best” by the numbers (which I happen to think misses 
a lot of stuff), it’s really hard to beat the newer SDR boards …..

Bob


> On Jan 7, 2018, at 7:38 PM, Perry Sandeen via R-390 <r-390 at mailman.qth.net> wrote:
> 
> YoDudes,
> 
> 
>  
> OK,OK, OK. I’ve taken the bait, so here are my comments.
> 
> 
>  
> Ireadily confess that I’m a perfectionist like Tisha but I’m far behind in the “doingit”
> 
> 
>  
> Aslight recap before I get on my (nice) rant. There have been major changes inmy life. Briefly, I just turned 77. We are forced to leave California and tentativelyplan to move to South Carolina where comparable housing is 1/4 the pricehere.  Taxes and utilities also are substantiallyless. Gasoline is $2 a gallon less.  Thereis no PC.  I don’t have to be concernedabout someone knowing I have firearms.  Ican buy ammunition without registration to the state with all my life’s detailsfrom childhood on. That's for starters.
> 
> 
>  
> Forour non-USA members let me give and illustration.  Here if your neighbor see’s strangers takingyour 70 inch TV here, they will take a video, posting it on Facebook andYouTube, and text their friends. They might think to call 911. 
> 
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> InSouth Carolina and most of the other states if this happens: 911 gets calledand an armed confrontation will take place. You will not go to jail for saving your neighbor’s TV.  
> 
> 
>  
> Thereare some other prurient family details that have sapped most of my energy.
> 
> 
>  
> Well,back to the good stuff.
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>  
> The “A”was made better sounding and useful for DF work in Viet Nam.  Collins took the IF out of the Non – “A”,made a few minor mods, and then it was rebranded as the R725.  It is an upgrade that can be done by usowners.
> 
> 
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> Boththe “A” and SP 600 can be made much better by a number of incrementalimprovements. Ray Osterwald, editor ER magazine, Dallas Lankford, Chuck Feltonand other have published articles and theirs and a few more are incorporatedinto my heretic “A” and SP 600 schematics. Also the Y2KR3 and the SP-600 anthology have almost all of theimprovements documented.
> 
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> It’sall up to what you want, your mechanical and soldering skills, and time.  All the mods except the R725 conversion arelow budget. Low budget meaning less than $100.
> 
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>  
> Neitherradio being 50 to 60 years old can or should be compared to modern ultra-uber$9K rice boxes.
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> Thereal question is: does it do what want or need to do and can it be made to meetyour needs with your time and skills.
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> Iwould wager that the improved receivers would meet all but the most super-esotericneeds of receiving.  If you have thoseneeds, go buy a $9K rice box.
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>  
> Onelast rant.  I’m sick and tired of hearingthat “mods” have to be reversible for the next owner. WTH?  These aren’t priceless irreplaceableendangered species.  The other sacred cowis “don’t drill any holes”.  So what andwhy? Most of us don’t want are radios to look like Bonnie and Clyde’s car whenthere were killed. But it’s someone else’s radio that that person decided todrill holes. Don’t like it? OK, but no one was anointed as the public’s radio commissar.Just shut up about it.
> 
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> Now I’vebeen mild mannered, circumspect, respectful some idiot ideas.  If this hasn’t worked, I’ll try to be moredirect nest time.
> 
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>  
> Regards,
> 
> 
>  
> Perrier 
> 
> 
>  
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