[NLRS] Accessory plugs for TE amps

[Dr. Gerald N. Johnson]

I think I used the tube socket scheme to replace the 2nd mixer in my 
75S-3B about 1965, there it was a 9 pin that I needed. The new mixer had 
a lot lower noise than the original 6AU8 pentode. That let me lower the 
gain in front of it and not hurt the system NF and improve the intermod 
products on 2m drastically.

There will be 1mm brass rod from K&S Engineering in most hobby shops and 
some hardware stores. It probably only comes in a package of 3. I think 
the steel core of the copperweld would make a better pin either from the 
1" spaced open wire or the center of RG-6. I'm sure some RG-6 has 
aluminum core which wouldn't give the stiffness of the copperweld. #18 
wire copper, or copperweld is .040" diameter like a tube pin. 1mm is a 
split hair smaller, .03937". Tube sockets are flexible.

Note if you decide to make a plug by drilling the hole pattern in some 
plexiglass, divide the pin circle in 8 equal spaces, just leave out one 
place for the locating space that takes the place of the locating post 
in an octal socket.  Laying out 8 equally spaced holes takes about a 
minute with a compass starting with a straight line, use the compass to 
make a right angle, then split one or both of the right angles to get 45 
degree spaces, or draw it in 17 seconds wit a 45 degree right triangle.

A half inch PVC cap might be close, a half inch copper cap would be a 
perfect fit being 5/8" inside diameter. Half inch PVC will be big, since 
its like 1/2" iron pipe dimensions. 3/8" PVC would work but is rare if 
its ever been made. A coax connector cap, either for UHF or N would be 
close, and the back end of a PL-259 threaded ring could be plugged with 
plastic to make a cap. And I'm sure digging in the pipe end protective 
caps in a good hardware store will turn up some 5/8" ID because that is 
the OD of 1/2" copper water pipe.

A nylon or PVC plug for 3/4" vinyl tubing would probably be close to 
5/8" inside diameter and could be shortened to just one or two 
corrugations with a hole in the end for the cable.

73, Jerry, K0CQ

On 12/21/2012 4:59 PM, Doug Reed wrote:
>
>
> The tube socket is a trick I never thought of. Good one!
> And you could probably find small diameter brass rod at a good hobby
> store. You can always measure the diameter of the pin on a tube and find
> rod stock to match. But buying a foot or two of RG6 wouldn't break the
> bank either.
> And you could take the tube socket to the hardware store and see if a
> plastic or copper pipe cap would fit as a cover that could be glued on
> the back.....
>
> 73, Doug Reed, N0NAS.
>
>