You might wish to experiment with Steward mix 35 or 40 toroids. Mix 35 has a relative permeability of 5000 and mix 40 is 10,000. Fair-Rite's 31 material has a relative permeability of 1500.
Digikey carries several sizes of toroid cores in mix 35 and 40 at moderate price. Search DigiKey's web site for 35T or 40T to see what they have available. For example, a 1 inch OD core is $1.19 in single lot quantities. Smaller cores, 0.54 inch OD, are 23 cents each in single lot. Steward's 35 and 40 material are MnZn ferrites and will have dimensional resonance in the HF frequency range, with the exact frequency depending on the core dimension. I suspect that dimensional resonance won't be an issue for a current choke at your frequency range, however. Fair-Rite claims the 31 material, although also a MnZn ferrite, does not have dimensional resonance. Type 43 is a NiZn ferrite and does not have dimensional resonance in the HF frequency band. Jack K8ZOA Julius Fazekas n2wn wrote: > I know there are several folks here who could answer this questions. > > I'm looking to improve my current chokes for my 160 and 80 Tx antennas. I was > planning on going with -43 material, but after reading thought -J and/or -31 > mixes might be a better solution. > > The 31 mix seems a bit more difficult to find "cheep". J material is a bit > more common on the excess sites. Would I notice a difference? > > Currently, the 160 antenna is a Tee Vertical. 80 is a dipole, but looking at > adding a Delta Loop now that I cleared out some brush... > > Thanks in advance... > > 73, > Julius > > > ----- > Julius Fazekas > N2WN > > Tennessee Contest Group > http://www.k4ro.net/tcg/index.html > > Tennessee QSO Party > http://www.tnqp.org/ > > Elecraft K2/100 #4455 > Elecraft K3/100 #366 > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
