[600MRG] RAKs and such

[kgordon2006 at frontier.com]

On 3 Nov 2014 at 9:37, Rudy Severns wrote:

> Those are some interesting mods for these old receivers.  Both my RBA-1 and 
> my RAK-7 are pristine, with no mods so I'm pretty loath to mess with them.

I certainly wouldn't do anything to either of them: they work just fine as they are. 

The only thing the RAK would need is that the mica coupling "condensers" between the 
stages sometimes begin to leak, causing a static-like sound that sounds more like far 
away lightning crashes than anything else. 

I have never had any of the oil-filled bypass capacitors go bad. though, except in one 
RAK-8 I have here which was stored upside down in its original crate for many years. 
The oil leaked out of several of those condensers, making a real mess inside the 
receiver. Even so, it still worked perfectly when it was connected to a power supply and 
fired up.

The original method of bypassing that first audio filter, which RCA used with the RAL, 
would be very easy to implement with the RAK, though, if you ever thought you might 
like to try it. It takes only one switch.
 
> I don't even want to change the antenna connector which brings me to a 
> question:  does anyone have a source for the cable ends that plug into the 
> antenna jacks?

I may have one or two of those here. I'll look for them as soon as I can. They are a 
special type of "coax" connector that the U.S. Navy used, and I have never seen them 
anywhere else.

> If not the connectors at least a good picture of one so I 
> might fabricate something.  I have no memory of what they looked like.

I'll send you a photo as soon as I can.

> I would also love to have one of the P/S connectors for the RBA.  Right now 
> I've kept the original female connector on the receiver and just inserted 
> pins as a jury rig.

The P/S for the RBB and RBC is identical. I know there is a fellow who sells stuff on eBay 
who has them. Also, William Perry specializes in those types of connectors. He is on the 
web. You might ask him about both the antenna connector for the RAK/RAL and the P/S 
connetor for the RBA.

BTW, I have one RBA which was modified by RCA to tune down to 14 KHz.

Also, the only real differences between the RAK/RAL 5, 6, and 7 were the antenna input 
cicuitry and the  connector. The only difference between the RAK/RAL 7 and 8 were 
almost purely cosmetic.

> I have the original P/S for the RAK but I don't use it.

It is awfully big and way "over-kill". I sold all of my original RAK/RAL power supplies 
some years ago to a collector out on the east coast somewhere. I have no idea why he 
even wanted them. I have one left.

>  I've built up a 
> separate more modern supply with various outputs which I can use on several 
> different receivers.  I use the same connector for each receiver but connect 
> only those pins with voltages unique to a particular receiver.

I have several dedicated power supplies for only the RAK/RAL. Much smaller, and work 
just as well. The power requirements for the RAK/RAL are very, very small.

Ken W7EKB