I had a rummage in my s2p library of old autotransformer models and found an s2p file of a basic 9:1 autotransformer wound on a 61 material toroid. This was not a great transformer when it was tested as you can see in the second plot below.
However, I tried simulating it along with a pair of MMBFJ310 JFETs in parallel. The performance was much better than I was expecting. It managed just over 10dB gain up to almost 75MHz and the results were close to that of the HR magazine for the amplifier in figure 5 of the magazine article.
Note that I did struggle a bit with the 1.4uH inductor. Up at 75MHz the behaviour of this inductor will depend on the way it is designed and wound and also on its Q up at 75MHz. I found I had to put a 4k7 damping resistor across the inductor model to prevent excessive peaking up at 75MHz.
See the simulation plots below. Of all the amplifiers I've looked at so far this one is the most interesting. I think it deserves a better transformer than the autotransformer model I used in the simulation. This autotransformer was not wound the same way as the 9:1 transformer in figure 5 of the HR magazine. I didn't use three twisted wires. I just used a classic tapped autotransformer with 1 main winding wire tapped a third of the way along.
The inductor can be dispensed with if you are interested in HF. It has no effect on NF or anything else besides VHF gain (and I suppose S22.)
I tried the figure-5 amp just now with a CPH6904 (dual CPH3910) at its max Id of 40 mA in place of the E430. It worked fine. Best performance I saw was 12.7 dB of gain at 50 MHz with NF in the 1.5 dB range. At currents less than 40 mA, the VHF gain fell off, the HF gain came up, and the NF was largely unaffected. The input impedance varied quite a bit with Id.
I didn't see any peaking, but I also didn't try any inductors other than the 910 nH / ADT9-1T combination in green.
Reverse isolation is more like 30 dB rather than 36 dB predicted by the article, but I didn't characterize it versus Id. I also didn't check IP1dB but it was +6 dBm with a single CPH3910 configured for 10 dB of gain at 10 mA, so likely better now.
Of course 40 mA at +/- 12V is almost a watt, so you wouldn't normally run the part this hard. (Edit: there is also some saturation in the Mini-Circuits transformer at this current level, so AC-coupling the transformer buys another dB or so of gain. NF is unaffected as is the oddly-poor LF performance.)
Good part. Everybody buy lots of them, so they keep making them.