>
>I looked at a couple of web sites selling those RJ-1 relays and couldn't
>find a good explanation of how they work. How many contacts do they have? I
>want to replace the open frame relay in my old Henry 2k-3. It is HUGE. The
>area were there is no shielding is about 3 inches long. This has little
>affect on the lower bands, but the higher bands seem to be affected. I have
>a 2:1 swr on 10 meters with the amp off into a dummy load. After looking
>carefully at the relay contacts (and cleaning them) I think that the length
>of the relay contacts is the culprit.
? the bypass swr problem can be corrected with very roughly 30pF of
shunt C.
>It probably causes a loss of
>efficiency there also. Anyway, the question is: Do I need two relays, one
>for input and one for output or does the RJ-1 have enough contacts to handle
>both.
? The RJ-1A is spdt. I know of no suitable dpdt relays that are fast
enough. The input end can be handled by a Matsushita RF reed relay.
See my Web site for details.
> If I need two is it ok to use a small open frame relay on the input
>and the vacuum relay on the output?
? only if the input relay can switch in under 2mS.
>
>I have two NCL-2000's that I would like to "modernize" also. Any advice
>would be greatly appreciated.
>
? The high-current internal screen supply is potentially a killer of
tubes. I would switch to a shunt screen regulator using a zener-string
of twenty, 20v/5w units, mounted on a perfboard, biased from the anode
supply through a suitable dropping resistor. RCA recommended some RF-NFB
R in the cathode. .Due to the extraordinary amount of VHF gain, I would
use lower VHF-Q parasitic suppressors. High speed switching would be
nice. // If you are interested in rx a copy of a revised NCL2000
diagram, send me a postal address and I will mail one.
- cheers, Martin
Rich...
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
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