Jerry, Very interesting stuff! I had not looked at your "parallel-tuned-circuit in parallel" option before; I just modelled it in EZNEC to learn more and saw some interesting results. I took a dipole
Jerry, Spent a few more hours this morning investigating the "parallel-tuned-circuit in parallel" option using a spreadsheet. I learned a couple more things: 1) Even when the tuned circuit does a rea
I have found EZNEC to be a really useful tool for getting a better understanding of how an antenna works, and for learning how different physical attributes affect the various antenna performance par
Just to be clear: what gives a folded dipole a slightly greater VSWR bandwidth is NOT the "fold" - that simply causes an impedance transformation. It's the presence of the spaced second wire that mak
Jerry I reckon you did a pretty good job without access to NEC. I just modelled the arrangement using EZNEC and tried a lot of different combinations of L, C and the length of the 75 Ohm section. At
I have a CorsairII, an OmniVI, a HerculesII, a 238 ATU, a 260 PSU, and a 263 Remote VFO all sitting alongside one another on my operating table. Only today did I notice the subtle differences between
Carl, Good, so I'm not colour-blind :) Where are they available? Steve G3TXQ _______________________________________________ TenTec mailing list TenTec@contesting.com http://lists.contesting.com/mail
Jerry, I understand that, but these are all the "Corsair II style" equipments. Take a look at the shack: http://www.karinya.net/g3txq/shack/ You'd have to see them next to one another to spot some of
I've been experimenting with ways of constructing 75 Ohm twin feeder for a Hexbeam application - it's now very difficult to get the heavier duty commercial cable - the only manufacturer in UK has cea
Gary, I've tried "lamp cord" for QRP work in the past; this time I was looking for something that would handle the UK limit of 400W. Also, the "lamp cord" I tried was closer to 100 Ohms which is too
Marinus, Yes, the CobWebb uses twin speaker cable, but not as a transmission line. It's used to form the folded dipoles. 73, Steve G3TXQ _______________________________________________ TenTec mailing
Jim, I'm trying to avoid coax in this application, because folk seem to have difficulty making off the tails; hence my interest in twin feeder. If folk can cope with coax there's no problem using RG2
Jerry, That would work, but using four lengths of coax to replace one seems a bit OTT I've just ordered a short length of RG-400 to try in place of the RG-58. It seemed to me the outer jacket (FPE) w
Right, Lee - that's exactly how I adjust my OmniVI / HerculesII combination. It's reassuring to know that once you've set the POWER control in TUNE, you can't overdrive the amp. 73, Steve G3TXQ _____
Jim, If you turn the POWER control on the Omni down low, switch to TUNE, then slowly bring the power up using the POWER control, what's the power output when the OVERDRIVE light first comes on? Steve
Hi Lee, Like you, I'm trying to get Jim to tackle this systematically. I think it's worth a first step of checking what power output he gets from the amp on TUNE before the OVERDRIVE LED comes on. If
Ken, Very useful info on setting up the XTAL OSC frequencies, thanks. I, too, managed to fracture a core and had to take out the coil. Be VERY VERY careful getting the coil out. If I recall correctly
I just got a length of RG400 to experiment with in the "twin feed" configuration - I'm quite pleased with the results which should be fine for my HexBeam application. With the measured braid diameter
Jerry, RG400 is available in the UK in lengths as short as 1m, but it's not cheap! 73, Steve G3TXQ _______________________________________________ TenTec mailing list TenTec@contesting.com http://lis
Hi Fraser, I have some of Westlake's "400W 75 Ohm twin" where both conductors are totally embedded within the dielectric material. Assuming the field between the conductors is mostly constrained to t