Dear all But before I go rushing off to Derek to buy some more, a simple sum casts some doubt on Peter's calculations. His loop has 2 metre sides and it has 4 sides so one turn equals 8 metres, not 1
The RSGB 'VHF' rally at Bletchley is this weekend. Is anyone from the reflector going? Perhaps we could meet up for an LF chat, althought that would probably be interpreted as 6m among the 'microwave
Regarding the use of a high loading coil, Mike (XDV) comments: It all gets back to the lessons we learned a long time ago about 160 metre mobile antennas. Get the loading coil above the roof of the
G4JNT wrote: I can supply an 81K size .PCX file of the full circuit diagram. If anyone wants a copy please contact me directly as it is too big to send on the reflector. Yes please Andy. Thanks for t
Andy 'JNT Could you give me info on the little pot-core you use for your driver transformer in your PA? Material, turns? I used a Farnell 559-570 ferrite sleeve, intended for EMC suppression, no info
Thanks to those who arranged the LF Forum at Wimborne yesterday. Jim and Andy gave most interesting talks and another gentleman gave a fascinating demo of a Tesla Coil. I counted 14 attendees - G4JNT
Me - G3OLB In message <[email protected]>, Talbot Andrew <[email protected]> writes Three said they were coming from the Crawley club, with the rest of t
Dear Group Just to report my findings of no measurable difference in antenna current when moving ammeter from hot to cold end of loading coil. Reads about 3.8 amps with 600 watts or so. Anyone need a
Thanks Andy - I was trying to get my head around the reason for high voltage AND high current at the top of the coil. You have explained everything we ever need to know about antennas in a few paragr
Hello all. Dave G3YMC has reiterated one of the common misconceptions about loaded antennas. There is no reason at all why the current out of the 'top' of the loading coil should not be exactly the s
Mabe some of the old 'bakelite' ones are pretty poor, but the ones I remember were made of white porcelain (I think) which should have good RF properties. 73, Tom G3OLB Doc.
Sorry to hear about your lightning strike Mike. Hope there is not too much damage. This discussion is certainly causing me to think about the whole issue, especially as my shack is in a converted sta
Use the formula Vrms = 4.44.F.N.A.B to calculate the Minimum turns needed on any given core, using a B of around 0.1 Tesla for a good safety margin. All non-gapped ferrites designed for SMPSU transfo
If you feed your antenna, as many do, via a matching transformer (3C85 core) then the antenna and the line to the tx/rx will be automatically grounded. Another advantage of this method of feeding ant
After lots of experimentation I ended up with only 75% of the original amount of wire I had in the air, but with about twice the original ERP for the same TX power. How do you know this Jim? By far f
Hello LFers A while ago I had an unexplained failure of the diodes in my LF SWR bridge. These were high voltage, fast diodes and I put it down to some kind of random failure. Last week end I noticed
In message <[email protected]>, James Moritz <[email protected]> writes Only real problem so far was getting the gate driver to work - even with both sections of a TC4427 driv
