[Amps] LDMOS Solid State Amplifiers

[Bob Henderson]

OK Tom.  Thanks.  It looks pretty good when operating at the 100W level.

Out of interest, which Freescale device are you using and at what power
level do you intend to operate the finished amp?

73 Bob, 5B4AGN

On 5 May 2012 15:30, Tom Thompson <tlthompson at qwest.net> wrote:

> Bob,
>
> Vdd was fed in at the U point on the brass tube, single turn, point.  If I
> switch back to that transformer, I'll try the bifilar choke feed and
> report.  I did some IMD measurements this morning.  I fed the amp with two
> Norcal 40 QRP transceivers on 40 m.  The input IMD due to the combiner
> isolation was -44 dBt where dBt means below one of the two tone peaks
> instead of the carrier which if present would be 6 dB higher.  The
> contribution from the input IMD is given by B = 20Log(1+10^(-A/20)) where A
> is difference in dB between the input IMD and the output IMD.  I measured
> an output IMD3 of -32 dBt at 100 watts on the amp under test.  That makes A
> = 12dB therefore B = 2dB which makes IMD3 = -34dBt.  IMD5 was -60dBt and
> IMD7 was -52dBt.
>
> 73   Tom   W0IVJ
>
>