[Amps] Relays

[Roger (K8RI)]

Alex wrote:
> OH, YEAH!
> Back in the sixties the radio Bible carried for years a T/R switch based on
> a triode. It was based on the principle of grid leak bias i.e. the RF
> developed bias for the tube to cut it of and thereby divorce the radio from
> the antenna during transmission.
> If I can find the schematic I'll scan and post it.
> 73, Alex 
>
> -----Original Message-----
> From: d.cutter at ntlworld.com [mailto:d.cutter at ntlworld.com] 
> Sent: Wednesday, April 02, 2008 12:31 PM
> To: Alex; 'Kim Elmore'; 'amps'
> Subject: Re: Re: [Amps] Relays
>
> Back in the days of steam radio, didn't we use TR switching using bottles?
> I seem to remember an 807 used as a switch, but the memory dims and I'm not
> next to my library to look it up.  Do we *have* to detach the PA on receive?
> Perhaps there's a way without resorting to PIN diodes, but then, someone
> would have thought of it already.
>
>   
My first transmitter was a pair of 6L6s stuck in the corner of one of a 
huge, steel TV chassis.  It eventually ended up with either a 12AT7 or 
12AX7 as a TR switch.  (Novice running QSK<g>)
When I moved up to a Viking Ranger the transmitter portion was removed 
from the chassis, but the TR switch remained.  I set the Ranger on the 
chassis with the RME 6900 next to it.
The handbook I used was the "Green" one that fell apart. Nearly all the 
Green ones fell apart.  I have one of the old "Blue" ones from the same 
period out in the shop. I'll have to take a look.

73

Roger (K8RI)
> David
> G3UNA
>
>