[R-390] R-390A /CV-157 /CV-591.

[Fernando Quinones N2FQ]

Hello

I've been lingering in the background and wanted to say thanks for  
this tidbit.
I have just installed my 390A in a 6ft rack and according to your  
comments,
I can see why I had difficulty in lining up the holes.

Now I'm enlighten and thanks.
Notice that I have some space between them that are not uniform but  
gets them off the floor.

<http://pages.sbcglobal.net/n2fq/_images/r390arack.jpg>

take care

On Nov 2, 2005, at 5:06 PM, Flowertime01 at wmconnect.com wrote:

> John,
>
> You ask if anyone here suggest a way to find a CV-157 , or a CV-591  
> cabinet.
>
> The R390 and R390A mostly did not come in a table top cabinet like  
> the ones
> you refer to. Mostly we were mounting them two or more in upright  
> racks or side
> by side in a sloped front double wide cabinet.
>
> The receiver has a standard 10 1/2 inch 6U high front panel. A "U"  
> being 1
> 3/4 inches. I have no idea who standardized the U at 1.75 inches.  
> and decided
> things should be in multiples of that unit.
>
> Blank panels come in 1.75 high increments. And they are all 19"  
> wide. 24" is
> also another standard width.
>
> Finding a table top cabinet that is deep enough can be a problem.
>
> HP put some signal generators in some standard cabinets with RETMA  
> mountings.
> RETMA being the standard hole pattern that goes with the U panel  
> heights.
>
> Once you under stand there is a method and pattern behind the  
> madness you see
> the logic in the hole patterns along the sides of most military and  
> heavy
> duty test equipment. Lots of it comes out of the little cabinets  
> and get mounted
> in big racks in the shops and labs where it lives forever.
>
> You can find short "table top" cabinets around. Watch your local  
> swap meets.
> If you live near a big military contractor, watch for their surplus  
> sales.
> These guy will some time put stuff out for sale. Hughes use to do  
> employee
> preference sales on the first Saturday of the month in Fullerton  
> California. Boeing
> did sales in Washington. Rockwell did sales in Los Angles.
>
> Any way there are commercial cabinets available as used equipment.  
> If you
> find one a bit more than 6 U high, you can put the receiver in it  
> and fill in the
> extra space with a blank panel of 1, 2, 3 or more U high.
>
> Cabinets are listed new in catalogs but the price exceeds the price  
> you pay
> for the radio. Shop around until you hit the $40.00 range for a  
> good looking
> used short rack.
> Full "6 - 8 foot cabinets closed on sides with a back door can be  
> had for $80
> - $100 dollars. You can also find short 4 foot floor racks. some on  
> casters.
> Lots of these were old computer cabinets and are floating around.
>
> The rail pattern is a standard pattern in all these cabinets. Any  
> of them
> with a rail set 19" wide will work. Some have threaded rails for 10  
> x 32 bolts.
> some have holes and use a tinner nut (cheep "yea cheep" not the  
> cheap) nuts or
> a good nut with a retainer clip that go with the rails. There are  
> also "nut
> bars" which are strips of metal with 2 or 4 tapped holes that fit  
> the RETMA rail
> pattern. Any of this hardware will work.
>
> Try not to hang your R390 by the front panel. The receiver weight  
> is to much
> for the front panel to support. The panel bends and will not look  
> so good.
> Just because you can do it does not imply you should do it. The  
> cabinet should
> have some blocks put in the bottom to support the receiver. Some  
> table top
> cabinets will have internal rails to support the receiver. Floor  
> racks typically
> have a set of rail holes inside to mount rails on that support  
> stuff bolted to
> the front panel. These side holes and rails are also a standard  
> type item. The
> rails are usually a 2 inch by 2 inch chunk of angle iron. In floor  
> racks the
> back rail set is adjustable to fit slides and mounting rails. For  
> being a
> standard item the stuff I have seen inside floor cabinet has ranged  
> all over the
> spectrum. But it will all bolt up a lot like an erector set.
>
> I hope this opens up your search window and you find a nice cabinet  
> for your
> receiver.
>
> You would like to have your receiver in a cabinet. If you wind up  
> with a
> floor cabinet someday, remember you want to keep it enclosed and  
> grounded. The
> whole idea of using a steel cabinet with an R390 on a table top is  
> to shield it.
> Shield also implies ground. The R390's (and A's) will pick up a lot  
> of local
> signal that mixes to noise in the audio output. Placing your  
> receiver in a
> cabinet helps. Consider that at 30 Mhz a 1/4 wave is still several  
> feet long. So
> small slots are still effective shields. If the AM band 1/4 wave is  
> very long,
> an open cabinet side is not a shield. There is some rational  
> between slots and
> screens being OK in shields and real big openings being not so good.
>
> Roger KC6TRU
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Fernando  N2FQ
<http://pages.sbcglobal.net/n2fq>