That Extra R.F. Stage!

Radio Record, Volume II, Issue 14, 19 October 1928, Page 27

That Extra R.F. Stage!

Another Success.

TNDER the date of October 3, a Nelson constructor seut the following enthusiastic letter which we print practically in full. Dear "‘Megohm’-Just a line to coneratulate you on the design of B.D. Shielded set. L have constructed this receiver and find it to be remarkably seusitive. Allow me to say that I have not stuck to all the features embodied in it. For instance I am using condenser control for reaction which I consider much better than the ordinary tickler. This does not de-tune the set at all. Secondly I found that it was very difficult to neutralise the RI. b) the crdinury neutrodyne way, I mean the tapped secondary. It worked al right on the first stages but not a hoy on the second. 1 therefore tried the split primary method and found that this was simplicity itself. It neutral. ised perfectly. Although 1 quite ap preciate your idea of making a separ: ate amplifier, I though I would like this section embodied in the set so nilowed extra space to take it and alsy the reaction condenser. The only yther alteration I have made 1s to cut mut the filament rheostat on the detec: ‘or and put in a fixed filament ballast. i don’t thing these alterations have nade the set any less efficient, perhaps more so as I eannot imagine a five valve receiver being more efficient. Bejeve me, I think it is simply wonder‘ul. 2FC comes in on the speaker at Mid-day. To-day, lL had the Sydney G.P.0O. chimes striking twelve at quite vood strength. I completed the set Inst Thursday and on Friday and Saturday nights, I] had KEX Portland, Cal. that loud on my amplion A.R. 19, that it could be heard all over the house. Yesterday at 1.30 p.m, 2FC came in so loud that my wife came in and said: "What station is that?’ "OKC," I answered. "Oh, really, I could hear it out in the kitchen and thought it was 2YA opening up to tell us the ‘Southern Cross’ was leaving." This sounds a bit tall but believe me it is "dinkum." © It is doing what a well-known "six" won’t, though they have a big reputation for pulling distance. In conclusion, I must thank you very sincerely for all this. I have built several BD’s but have never made or seen a five-valver like this. Four of the valves I am using are 201A Radiotrons which I have been using for the last three years. The detector is a PM6. Several of the fans about here show great surprise at the results and some others, on being told about it won’t believe. I omitted to say . that 8YA is very difficult to pick up

here on 5 valves duri. the day, but I can now -get it on the speaker, O.K. All the A class "Aussies" and all N.Z,.’s come in with great volume at night, no reaction and filaments cut down. I don’t think there is a station in Aussie or N.Z. that I can’t get on the speaker. The Japs also, KGO, KEX, and a couple of others. I haven't heard the eall of yet. I could go on praising this set all night but I suppose you have had enough by now.