Its been awhile since I last posted but a lot has happened, not the least of which is downsizing to a Bungalow all of which has meant that for a long time I've had no time or space to work. Well the bulk of work has been done and I now have what you might call a study bedroom with on suite loo makes me feel like I'm back at uni in the sixties. Anyway I digress lets get back to the Eddystone.
The first time I switched on the 870 all went well, tune up the IF amp after that it worked a bit better but it seemed as if there was not as much gain as there should be so I decided to chuck a wire out of the window and down the hedge and use the central heating rad as earth. I set the aerial links to unbalanced input and switched on and pop of went the power, to the whole house..!! Turns out the new (well 26 year old bungalow has an RCB and it didn't like the live chassis and the asssociated coupling cappacitor, wasn't too keen myself so I decided it was time to make it safe and found a toroid transformer that had a primary of 240v (2 x 120) and an output of 110. The mains filter had to go to make room for it, see top right, it also meant that the dropper was now bypassed when I switched on everything worked ok no sudden loss of Corrie Street so all was well with the world.
Later I did some more work on it wave change position 2 was a bit dodgy the oscillator didn't start up unless you fiddled with the switch turned out it was a dodgy earth on the beehive cap that was at fault. In the process of probing around I moved some componets arround and found a wire whisker that was shorting the 2nd IF transformer output and the set just pop into life. I retuned the IF with the sendon IFT now working and it seemed quiet lively however the tracking is a bit out as my £5 valve sig gen calibration is just not reliable so the next thing to do is make a crystal calibrator / marker so I can get to the nearest 10khz or so. We have a lot of work done with tv aerials in the loft so I got them to rig me a doublet with ribbon feeder and two 10m legs (the length of the loft).
Still not quite there but its safe and seems to work reasonable well
