Re: [time-nuts] Active LF Antennas
Hi John, I think Lyle Kohler K0LER (?) has a version with the J310 on his site. I have seen cases were J310s were placed in paralled to get better IMD performance and maybe lower noise but that is not a problem at LF. They do work well but like all voltage probe antennas need mounting high for best performance. Another fairly popular antenna in the LF field is a circuit by Roelof Bakker PA0RDT where the whip is replaced by a square inch of PCB pad. This has proved exceptionally good in some noisy urban appartments and hotel rooms mounted out off the balcony on a length of cane. Alan G3NYK - Original Message - From: John Miles [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: 20 July 2007 04:55 Subject: Re: [time-nuts] Active LF Antennas Since the article and FAQ on the AMRAD site were written, the split bobbin transformer is has become available from Digi-Key. You don't have to special order it. I was glad I ordered 10 of the Crystalonics JFETs for that project. Four of them were defective as delivered (D-S short). You can save some bucks by going the J310 route first and upgrading to the CP666 only if you actually have IMD problems. -- john, KE5FX ___ 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] Active LF Antennas
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] In a message dated 20/07/2007 03:51:20 GMT Daylight Time, [EMAIL PROTECTED] writes: Brooke - you scored a bullseye on that one. I had a couple of false starts, but got an email back from Frank Gentges suggesting I contact Far Circuits for the PC boards ($11.50 for the set which includes shipping). Now to obtain the rest of the parts... - If you want to make a quick start on LF try a Google on pa0rdt or just take a look at this _www.veron.nl/afd/voorne_putten/Lezing/www.veron.nl/aMini-WhipGeneralDescripti on%5B1%5D.pdf_ (http://www.veron.nl/afd/voorne_putten/Lezing/pa0rdt/pa0rdt-Mini-WhipGeneralDescription[1].pdf) Via Google you''ll find info on work by Roelof Bakker aimed at reducing the element size on an active vertical and the pdf shows the result. a complete active antenna on a single PCB 90mm long and 30mm wide:-) There's been quite a lot of online discussion on the pros and cons of this, so don't really want to get drawn into it all again, but I have built them and they've worked well for me. Using a mini drill with an end burr tool to cut the PCB, or just a hobby knife will do, the module as described in that pdf can be built in a couple of hours at most, including the PSU interface. The 2N5109 suggested works fine but I've also used a 2N3866 with similar results. I've used one with a 2N3866 to receive the 17 KHz SAQ transmissions both from south east England, inland approx 25 miles north of London, and from the west coast of Scotland, in the middle of the Clyde estuary. In England the antenna was probably 5 metres above ground level, in Scotland approx 4 metres above sea level. MSF on 60KHz is very strong via the mini-whip here in Scotland, even given the lashed up nature of the test support, but since their move north that's probably to be expected:-) HBG and DCF77 are usable too, JJY has so far not been seen:-) My eventual intention for the mini-whip, as well as using it in it's own right, is to use it as a spotter for my rotator mounted Wellbrook loops so as not to miss things in the null. the best of both worlds:-) regards Nigel GM8PZR ___ 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] Active LF Antennas
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] In a message dated 20/07/2007 09:57:38 GMT Daylight Time, [EMAIL PROTECTED] writes: Another fairly popular antenna in the LF field is a circuit by Roelof Bakker PA0RDT where the whip is replaced by a square inch of PCB pad. This has proved exceptionally good in some noisy urban appartments and hotel rooms mounted out off the balcony on a length of cane Hi Alan After penning my enthusiasm for Roelof's efforts perhaps I should have checked back before hitting the send button. as I now see you beat me to it:-) regards again from the soggy north Nigel GM8PZR ___ 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] Active LF Antennas
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] Is the Doug Baker LF antenna still available? If so, how does one go about obtaining one? Get the Yahoo! toolbar and be alerted to new email wherever you're surfing. http://new.toolbar.yahoo.com/toolbar/features/mail/index.php ___ 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] Active LF Antennas
Tom - not a direct answer to your question, but as an alternative, Wellbrook here in the UK do a wideband amplified loop antenna - see: http://www.wellbrook.uk.com/products.html#LFL1010 Regards, Peter Tom Clifton wrote: Is the Doug Baker LF antenna still available? If so, how does one go about obtaining one? ___ 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] Active LF Antennas
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] Brooke - you scored a bullseye on that one. I had a couple of false starts, but got an email back from Frank Gentges suggesting I contact Far Circuits for the PC boards ($11.50 for the set which includes shipping). Now to obtain the rest of the parts... I received an HP-3586C via UPS today and it is in great shape. Hoping to do some playing around with LF as well as FMT with K5CM and his gang of FMT-Nuts... So many great ideas and only 24 hours in a day... Building a website is a piece of cake. Yahoo! Small Business gives you all the tools to get online. http://smallbusiness.yahoo.com/webhosting ___ 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] Active LF Antennas
Since the article and FAQ on the AMRAD site were written, the split bobbin transformer is has become available from Digi-Key. You don't have to special order it. I was glad I ordered 10 of the Crystalonics JFETs for that project. Four of them were defective as delivered (D-S short). You can save some bucks by going the J310 route first and upgrading to the CP666 only if you actually have IMD problems. -- john, KE5FX ___ 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.
