Dear Roelof and Petr When I first tried the mini-whip I was very sceptical of its performance, but in my circumstances, living surrounded by houses and near a main line electric railway ((25kV) it ha
Hello Minto, In laboratory tests it is possible to tweak the bias of the J310 for a very high IP2 of +80 dBm and a IP3 of +33 dBm. However this does not hold in off air tests. I use the medium wave s
Hello Ken, I use 40 mm PVC pipe with an end caps at both ends. The end caps are glued with PVC glue to the pipe and this is watertight. The bottom end cap does hold a BNC connector and has a 1 mm ven
J310's are still plenty available (at least her in PA country...) 2N5109's however are not. A BF199 seems a bit too small for the dissipated power...? I used a 2N3866. seems to work well but I have n
Hello Roelof. Very interesting, I am just about to commission my MiniWhip, the hold up has been several things, firstly winding a high value power take-off inductor, but mainly what to seal the ends
We actually did seriously consider this as a solution to a a very difficult problem in an industrial situation some years ago when we were colleagues and dealing with a situation that involved both e
Hello Peter, The J310 is the best choice, I found so far and these are cheap and widely available. However, you can try anything you have at hand. A good modern replacement for the 2N5109 is the BFQ1
May be mistypo? BF245 is a N JFET, BC245 I don't know. Regards D. From: DENNIS EASTERLING <[email protected]> To: [email protected] Sent: Sun, January 16, 2011 9:16:36 PM Su
I'll join the show my mini-whip discussion. The antenna is amazing as most everyone knows by now. I recall Mitch Powell, VE3OT, building one in the base of a 6V6 using the tube's plate for the antenn
Hi Roelof, Some interesting comments there. On the topic of feeder pick up Alan G3NYK and myself have had many conversations over the years about ways to deal with the problem and a method we've neve
Hello Petr, Thank you for your kind words. When I became serious about listening at LF, I messed around a long time with loop antennas. Unfortunately these pick up too much noise for weak signal work
Hello Daniele, "Cases were the normal precautions like grounding the shield of the coax or the use of a rf-isolating transformer don't work". However, when the noise is radiated to the outside world,
Dear Roelof and Petr When I first tried the mini-whip I was very sceptical of its performance, but in my circumstances, living surrounded by houses and near a main line electric railway ((25kV) it ha
Hello Roelof, Yes at 200 mW there should not be a problem. I use a 2N3866 in my 2 mini-whips, on paper the 2N5109 en the 2N3866 looked comparable enough (as far as I remember). The mini-whip is much
Hello Roelof, It is an honour for me to have the answer directly from the author of this little magic thing. I didn't realize that you are on the group as well. How long did it take you to develop it
Hi Peter I used a BC245 JFET instead of the J210, and a BF199 for the 2N5109. No circuit modifications appeared to be necessary. 73 Dennis M0JXM Hi, Question: any experiences about comparable replace
J310 and 2N5109 both available from: http://www.jabdog.com/main-cat-index.htm (accept PayPal) or http://www.cricklewoodelectronics.com/Cricklewood/pages.php?pageid=10 73 Terry --Original Message-- Fr
Dennis, if the loop-preamp system is well balanced the loop doesn't need screening. E.g. the Wellbrook ALA1530 broadband loop is unshielded. Therefore its preamp is a push-pull design. 73 Clemens DL4
