12 volt valve regen receiver.

[ms660]

Haven't got one yet but found a supplier, not sure about auction rules, I never am even though it's been explained to me umpteen times... Anyways here goes for better or worse "DDS VFO" look for a New Zealand supplier 40 odd quid.

Lawrence.

[ms660]

In an earlier post I wrote:

"So to keep things simple I'm now veering towards a Direct Conversion receiver, the stability of a DDS VFO should allow AM broadcast reception as well as SSB/CW"

What appealed to me about the above was the fact that I would have a frequency readout of the transmissions received.

Anyways, while pondering over a cup of coffee a short while ago I got to thinking... I could do that with a Regenerodyne receiver as well

Make a note of Fo when the receiver is tuned to a transmission, tune osc down to the regen detector frequency, zero beat (the regen detector will be oscillating on SSB/CW) note the DDS VFO's new frequency and add/subtract from the first noted frequency, I say add/subtract, it depends whether Fo is set above or below Fs.

Think I've got that right, if so I'm back on the Regenerodyne idea now...

Lawrence.

[ms660]

I've been looking at valve data for the ECC82, looking ok so far for a 12 volt regen detector, low mu, low gk capacitance, can be run as a Hartley, might give that a go as first choice.

Lawrence.

[ms660]

I've taken the plunge and ordered a DDS VFO board, from what I can gather it's all ready assembled, just need to connect a supply and punch in beginning /end frequencies and maybe a couple of other parameters via the cal button and the rotary encoder.

The simplest receiver experiment would be to lash up a direct conversion jobie and maybe incorporate a regen rf amp to whack the selectivity up a bit taking into account balanced mixer signal overload, still heading for a valve hybrid job that'll work on 12 volts.

In the meantime I need to hone my trifilar winding skills and accumulate some general components to play around with as I have not a lot apart from a few odd resistors, it's like starting all over again...

Lawrence.

[ms660]

Talking of regen preselector here's an early one (Frank C Jones):

http://www.americanradiohistory.com/...io-1935-02.pdf

Lawrence.

[ms660]

The DDS VFO has arrived at last, came all ready assembled, supposed to run off 12 volt supply, haven't got that at the moment so PP9 it was, set min frequency to 500Khz, max to 35 Mhz IF offset to zero and spun it up to 30Mhz, encoder steps can be set to 10Mhz, 1Mhz, 100Khz etc down to 1Hz, all checks out ok on my basic 30Mhz 'scope, about a volt or so at that frequency (X10 probe) Seems rock solid frequency wise, it's the way to go Should be enough to drive a mixer of whatever persuasion.

Not sure when the next bit of the project will take place as I need to buy some bits to faff around with, I'll post in the Homebrew section as and when.

EDIT: To add photo's 'scuse grotty pics.

Lawrence.

[Colinaps]

low voltage regen - RC Feb 64.