John,
I would ask this question of Ohmite about their OX/OY series ceramic
composition resistors. Last time I asked them by posting a request on
their WEB site, they got back to me in a couple of days. See
www.ohmite.com.
Mike, W1NR
Thanks, Mike. I did that today. Hopefully they will give me an answer!
Hi John....
You didn't say what power level you were considering but I see in the
Mouser catalog
that they have Caddok power film resistors from 15-100 watts. Says they
are good
up to 500 mHz. These look similar to TO-220 transistors.
73, Roger
Thanks, Roger. I am not sure of the power level - somewhere < 15W. These are
grid swamping resistors and the actual resistance value (and therefore power
dissipation) will have to be determined by experimentation.
I think it's unusual to want/need grid loading at UHF. Given the
reactances in typical tubes, is 1k going to have much effect?
At resistances up to 1-200 ohms you can get low inductance in the
stripline resistors made by RF Power/Anaren, EMC, KDI, Florida Labs and
suchlike (some of these might be history).
Can you tell us more about the design?
Steve
Yes Steve. It is a K2RIW amplifier and is used for ATV. I am trying to
broadband the input to enhance a poor sound sub-carrier. I am not sure how
much
loading it will require (or whether it will improve the situation adequately).
Right now the amp is swamped with 10K a side. I will try 2K and go down from
there.
Thanks to all who responded. In the old days, carbon comp was the only game
in town. Today, there are too many new products, and they have left me behind
on the knowledge game.
My original question was:
At 07:39 AM 2/8/2007 -0500, you wrote:
>
>Hello all,
>
>Am looking to load a 70cm amplifier grid with about 1K or less of
resistance.
>
>This has probably been asked before, but what types of "non-inductive"
>resistors are non-inducive up to 1 GHz? And, if carbon composition is the
>only choice, where can you find 3W these days?
>
>I have found some sources state carbon film and metal film resistors are
>non-inductive, but rate them to 100 MHz.
>
>Thanks,
>-John, N9RF
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