Re: IRF510 amplifier failures

K9HZ <bill@...>

The RD15HVF1 has a bit of a flatter input capacitance curve with frequency so its easier to keep constant gain over 1-54 MHz… but the RD16HHF1 is certainly a worthy part too.  Oh, did I mention, they are both real RF transistors?



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email:  bill@...


From: [] On Behalf Of James Lawrie
Sent: Friday, January 26, 2018 2:01 PM
Subject: Re: [BITX20] IRF510 amplifier failures


On same site I found these, made for 30 MHz RD16HHF1. Sooo I bought 10 of them, plan to try in Bix40 first. Data sheet even shows a reference amp design, and they are 12 volt like the other one. If it works I’ll let everyone know.


James Lawrie

On Jan 26, 2018, at 11:32, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:

The RD15HVF1's should be operated at not much more than 12v.
At 12v, the IRF510's would survive just fine with no antenna connected.
That's an infinite VSWR.

So not obvious that this is a solution to blown FET's.
Though I do think the the Ids curves go up more slowly as Vgs increases on the RD15HF1's,
which makes RV2,RV3 not so touchy.
And the RD15HF1's might be easier to drive at 30mhz.
If you do swap them in, let us know how much power you get at 30mhz.

Jerry, KE7ER

On Fri, Jan 26, 2018 at 03:54 am, KD8CGH wrote:

Wouldn't it be better to change to a RD15HVF1 for high VSWR

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