Playing around with Tayloe Detector at 150 MHz

I had someone ask me whether my Tayloe detector board

Could work at 150MHz. I thought it might be interesting to have a go at that challenge starting with the band pass filter.

Here's devttys0's excellent BPF video with the "gimmick" cap

Here's an example of a double tuned BPF calculator

Resonance calculator

0:00 Intro
1:09 Modelling the BPF in LTSpice
2:09 Resonance Calculator
3:58 BPF in AC analysis
4:38 Undercoupling and overcoupling
7:47 First look on the spectrum analyzer - band pass frequency too low
11:07 Changed the resonator turns - second look

[nay]

Note: At around 3:00 I mentioned "5 turns less" - I meant to say "turns divided by 5". So say 15 turns on the resonator side would be 3 turns on the input side.

[ivolol]

Would have loved to see the effects of symmetrically changing the capacitance of the varicaps, and non-symmetrically

[Paul_VKHN]

Informative demonstration of BPF coupling. Those T37-0 cores must have mostly filler in the mix. Re link coupling into and out of BPFs at HF, I've always used 3T and have never seen anyone do anything to optimise the impedance match to 50r of these windings.

[andrethomas]

Very interesting diversion from your transceiver build :)

[johnwest]

The 'Mix 0' is just a phenolic form, isn't it? This project sounds like fun. I really like such experimental builds. BTW, I've used 'gimmicks' occasionally over the years. They always seemed like a shaky idea, but they always worked well and maintained their capacitance. Of course, that depends on the wire type used.

[herbertsusmann]

Interesting that you didn't tweak the two variable caps at all? That could have been all that was needed to get up to the 140-150 MHz range, no?

[RCBU]

Will it work up to the Nyquist frequency? Or above her?

[anthonyclark]

Gimmicks caps make sense for scenarios but nowadays with the range of ceramic capacitors available, they create more issues than they solve.

[anthonyclark]

If you make this work it will be a bloody miracle 😊 seriously use a single conversion Rx with an IF around 9mhz. This is what my current project is about. Single conversion hf transceiver using some of the ideas from your channel. No analogue audio switching, route i2s internally.

[anthonyclark]

I'm not knocking your try at this, but it has real difficulties. I've done this stuff in the past, a long time ago in the land of Oz. I live in nl these days.
My current RF knowledge is a bit rusty these days but if you want to bounce some ideas around I would be happy to pitch in.73s. a Long time ex vk6