View Single Post
Old 6th May 2022, 6:56 pm   #6
frsimen
Heptode
 
Join Date: Jan 2011
Location: Croydon, London, UK.
Posts: 767
Default Re: 3 Tube Ocean Hopper (battery type)

At the very least you need a switch to disconnect R2, otherwise that will still be drawing current when the filament supply is removed. Switching off the HT supply will reduce the risk of you getting a shock because you forgot that HT is still applied, even though the radio appears to be off.

You could connect all the earths for V1 to one point, those for V2 to another, so long as you keep the connections short.

To set the lowest frequency you will need to have some way to identify that you are tuned to the right frequency. Methods that you may be able to use are:

1) Use a signal generator, set to produce a signal at the lowest frequency that you wish to listen to. Adjust the band set capacitor to tune in the signal from the signal generator, with the band spread control at maximum capacitance.

or

2) If you have another radio that covers the frequency that you wish to set, tune that radio to your chosen frequency. It the radio has a BFO, switch it on. Adjust the reaction control (R2) so that the detector is oscillating. Adjust the band set capacitor until you hear you hear the oscillator of your battery set on the other radio. If the BFO is switched on, you will hear a whistle when the frequency is close to correct. Adjust the band set capacitor for the lowest pitch whistle. IF there is no BFO, you will hear a hissing as you tune to the right frequency, adjust for the least noisy his. It's hard to describe but you will understand when you try it.

or

3) Try to measure the frequency of the oscillation using a frequency counter with a pick up loop positioned near the tuned circuit.

Yes, R2 controls the amount of regeneration and that will alter the volume The sensitivity and selectivity are at their best when just below the point of oscillation, for AM reception. Go beyond that point a little and you will be able to detect CW and SSB signals.

Last edited by frsimen; 6th May 2022 at 6:57 pm. Reason: Typo corrected
frsimen is offline