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

[Leigh Sedgwick]

Very nice setup but why is it in the garage and not in the living room?????


----- Original Message ----- 
From: "Fernando Quinones N2FQ" <n2fq at sbcglobal.net>
To: <r-390 at mailman.qth.net>
Sent: Wednesday, November 02, 2005 6:30 PM
Subject: Re: [R-390] R-390A /CV-157 /CV-591.


> 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
>> _____________________________________________________________
>> R-390 mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/r-390
>> Help: http://mailman.qth.net/faq.htm
>> Post: mailto:R-390 at mailman.qth.net
>> Unsubscribe: http://mailman.qth.net/mailman/options/r-390
> 
> Fernando  N2FQ
> <http://pages.sbcglobal.net/n2fq>
> 
> 
> 
> _____________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/faq.htm
> Post: mailto:R-390 at mailman.qth.net
> Unsubscribe: http://mailman.qth.net/mailman/options/r-390