28-07-2020, 09:51 AM
I might be further away from both. It's possible that Spirit is aimed at NI as it's TX site is near the boarder on a piece that wiggles into N.I., There is also a Spirit FM, don't know where its TX is, but better VHF-FM sets here pick it up between RTE 1 and 2FM.
I used to get R.Ulster, but not often for some time, so I wonder was the TX power reduced. Never got Downtown; I was though still living in N.I. when Downtown started and before that had Manx radio on VHF with a home made aerial in the attic.
I shall use the other "scrap" chassis for a tester with a small resistor in each anode feed and the DK9x g2/coil HT feed. Then a six way switch to a cheap uA.
I'll switches for o/p valve filaments vs 1.4v only and alternate wired (DL95?), also 'd' and 'a' swap on the dectector.
I may add an extra socket that can take a DK9x, DF97, DC90 etc as an oscillator only.
But my next thing is using 2x 1j24b to exactly replace an 1L6 without realignment of the shorter bands. The DK96 replacement worked well. Sadly it went "pop" trying to test it on the AVO VCM163. I've concluded that you can only really test diodes, triodes and pentodes on it and it's useless for Heptodes, Octodes, Nonodes etc. Poor for testing Hexodes.
On a mixer you want to see the conversion gain and LO leakage on RF in.
On an oscillator you want to see performance at minimum LT and HT driving a mixer, or a simulated load. This applies to the g2 as a pseudo anode as oscillator on a Pentagrid or higher. You want to see effect of AGC on RF pin on the oscillator and the FM of the oscillator from RF signal. I'd never design with a Heptodes, Octodes, Nonodes etc as a combined mixer/oscillator as the RF in leaks too much LO and the LO is too much affected by AGC and RF out of band on the RF in; the separate oscillator - mixer, even as as Triode-Hexode or Triode-Penttode with a shared grid, or even the one that has a shared grid and cathode or filament between the two parts.
I used to get R.Ulster, but not often for some time, so I wonder was the TX power reduced. Never got Downtown; I was though still living in N.I. when Downtown started and before that had Manx radio on VHF with a home made aerial in the attic.
I shall use the other "scrap" chassis for a tester with a small resistor in each anode feed and the DK9x g2/coil HT feed. Then a six way switch to a cheap uA.
I'll switches for o/p valve filaments vs 1.4v only and alternate wired (DL95?), also 'd' and 'a' swap on the dectector.
I may add an extra socket that can take a DK9x, DF97, DC90 etc as an oscillator only.
But my next thing is using 2x 1j24b to exactly replace an 1L6 without realignment of the shorter bands. The DK96 replacement worked well. Sadly it went "pop" trying to test it on the AVO VCM163. I've concluded that you can only really test diodes, triodes and pentodes on it and it's useless for Heptodes, Octodes, Nonodes etc. Poor for testing Hexodes.
On a mixer you want to see the conversion gain and LO leakage on RF in.
On an oscillator you want to see performance at minimum LT and HT driving a mixer, or a simulated load. This applies to the g2 as a pseudo anode as oscillator on a Pentagrid or higher. You want to see effect of AGC on RF pin on the oscillator and the FM of the oscillator from RF signal. I'd never design with a Heptodes, Octodes, Nonodes etc as a combined mixer/oscillator as the RF in leaks too much LO and the LO is too much affected by AGC and RF out of band on the RF in; the separate oscillator - mixer, even as as Triode-Hexode or Triode-Penttode with a shared grid, or even the one that has a shared grid and cathode or filament between the two parts.
