Talk:T2FD antenna

message: I can't understand why the claim that the T2FD is relatively immune to local electrical noise is 'disputed'.  Any balanced-feed antenna will by definition 'phase-out' local electromagnetic noise - at least from the broadside direction.
This antenna works, by the way.  The small size (and especially the resistor) make it look like a dummy load on paper, but it isn't, (and I don't know why either! :-). It works even better if you stick a big piece of insulating tape over the 'S' meter and just listen. Chris G4PDJ (Contact via qrz) 08:44, 11 January 2007 (UTC)
replies: text: Hmmm...A bit of a sudden removal, but I won't bother putting it back in.  I still think that (although not essential) the use of an ATU is worthwhile, especially with modern-day solid state rigs.  The T2FD is very broadband, but can still present a considerable SWR at certain frequencies (mine ranges between about 2:1 and 3.5:1, which is not 'high', but still enough to cause some PA protection circuits to 'throttle back').  Obviously an ATU is not going to do as good a job of harmonic suppression or recieve preselection as a proper tuneable band-pass filter would, but it's better than nothing, as this antenna will by definition radiate just about anything that comes up the feeder.  A fairly cheap and cheerful coaxial ATU will do (maybe even replace the 'Ant' socket with a 75 Ohm connector for that finishing touch).  In most cases the SWR should be low enough to fall within the range of an auto-tuner too. (ChrisG4PDJ) 160.84.253.241 (talk) 09:35, 26 November 2007 (UTC)
replies: text: Thank You dear Spamhog.  I understand your point perfectly, and agree/know/and have done since the 1960s that an ATU will obviously not do anything like as good a job as a bandpass filter.  I just have difficulty understanding your logic ("Don't use anything because an ATU is not as good as a bandpass filter").  It's a 'Counsel of Perfection' like 'Walk, and never drive a Ford because a Ferrari is better'.  In the real world, and in this day and age, we all know that it shouldn't really be necessary to use anything to suppress harmonics, because a modern-day transmitter should hardly emit any in the first place.  But even a first-day SWL knows that 'wanted' signals increase in strength if you adjust the ATU and 'unwanted' signals get weaker.  So (unless somebody has invented electricity that works differently in different directions) there must be some degree of attenuation.  I was just tailoring my words to suit modern-day reality...Most Hams who would feel the need to consult a 'semi-layman' page like this are just looking for a quick-and-easy guide as to how to knock together a T2FD before simply hooking their ready-made Japanese box up to it via an auto-tuner.  So...lets not get bogged-down by a disagreement about harmonics which shouldn't even be there in the first place, but just say that "The use of an ATU may be beneficial with modern solid-state transmitters". ChrisRed (talk) 13:02, 29 October 2008 (UTC)
replies: text: p.s. For indoor receive-only T2s; a 1k Carbon-Track (i.e. not wirewound) Pot, superglued at 390 Ohms from track to wiper works just fine. Likewise a standard 300-to-75 Ohm TV balanced line balun like this [] (GB£2 or US$3). Don't forget to use 75 Ohm TV Co-ax, not 50 Ohm.  Don't bother with an ATU for receive-only. (G4PDJ) ChrisRed (talk) 11:05, 30 October 2008 (UTC)
replies: text: To Spamhog...Sorry, I haven't checked into this page for a year or two, but that photo you added is magnificent.  I've been off the air for a few years owing to living in a succession of rented accommodation, but now I'm 'back in civvy street' will open up the big cardboard box called 'radio stuff' and be coming back on the air soon with CW, PSK31 and a T2FD, whoopee! :-) (G4PDJ / ChrisRed)86.170.182.192 (talk) 00:24, 23 September 2010 (UTC)
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