[time-nuts] HP 117 from ebay
List, I bought one of them for several reasons besides that I really wanted it. 1. There is plenty of real estate to install Paul’s demod circuit. 2. It is large enough so the nuvistors can be replaced with dual gate mosfets (I have lots of them). Also sometimes replacement nuvistors can be obtained on ebay for a reasonable amount. 3. If needed, I believe most of the divider circuits can be relatively easily replaced with IC’s. However the first thing I will do before firing it up (figuratively or literally) is to replace all the electrolytic caps. I’m not interested in buying the antenna as there are numerous vlf antenna circuits with preamps for 60 KHz on the net. One suggestion I found interesting was the idea of filling your tubing with wet sand then using a truck tire to bend the loop. Where to borrow a truck tire? It didn’t say. Regards, Perrier ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 117 from ebay
IMO, it is unlikely you will be able to form the loop by hand on a mandrel. I'd suggest a commercial conduit bender for that trade size conduit and work your way along the tubing a few inches at a time. -John ===  List,  I bought one of them for several reasons besides that I really wanted it.  1. There is plenty of real estate to install Paulâs demod circuit.  2. It is large enough so the nuvistors can be replaced with dual gate mosfets (I have lots of them). Also sometimes replacement nuvistors can be obtained on ebay for a reasonable amount.  3. If needed, I believe most of the divider circuits can be relatively easily replaced with ICâs.  However the first thing I will do before firing it up (figuratively or literally) is to replace all the electrolytic caps.  Iâm not interested in buying the antenna as there are numerous vlf antenna circuits with preamps for 60 KHz on the net. One suggestion I found interesting was the idea of filling your tubing with wet sand then using a truck tire to bend the loop. Where to borrow a truck tire? It didnât say.  Regards,  Perrier ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 117 from ebay
Perry Glad the 117 found a home. That said don't be so quick to modify it. As an example the 3 nuvistors give an outstanding 120 db of gain. Hey if they work leave'em. Same goes for the dividers. But that said if something really is sick modify it. I would plan to if either of mine has a failure. I did have to replace one electrolytic. (White foamy stuff dead give away.) There is a lot of room for stuff inside and with todays technology it doesn't take much space. I also unplugged the strip chart recorder. I use an electronic program using a Dataq 4 cnl AD converter $25. That way I can log four VLF rcvrs at a shot. And its quite. No tick tick tick. Regards Paul. On Fri, Jul 26, 2013 at 12:57 PM, J. Forster j...@quikus.com wrote: IMO, it is unlikely you will be able to form the loop by hand on a mandrel. I'd suggest a commercial conduit bender for that trade size conduit and work your way along the tubing a few inches at a time. -John ===  List,  I bought one of them for several reasons besides that I really wanted it.  1. There is plenty of real estate to install Paul’s demod circuit.  2. It is large enough so the nuvistors can be replaced with dual gate mosfets (I have lots of them). Also sometimes replacement nuvistors can be obtained on ebay for a reasonable amount.  3. If needed, I believe most of the divider circuits can be relatively easily replaced with IC’s.  However the first thing I will do before firing it up (figuratively or literally) is to replace all the electrolytic caps.  I’m not interested in buying the antenna as there are numerous vlf antenna circuits with preamps for 60 KHz on the net. One suggestion I found interesting was the idea of filling your tubing with wet sand then using a truck tire to bend the loop. Where to borrow a truck tire? It didn’t say.  Regards,  Perrier ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
