I still have the file from which the boards were made via ExpressPCB; I'm sure Jerry also has a copy. If anyone wants a copy to get more boards they're very welcome. Might be a bit expensive for a on
The minimum price would be for ExpressPCB's "standard service" which does _not_ include silk screen or solder resist, but gives you a perfectly usable board. Minimum quantity is 2 for $94 ($47 each);
I've uploaded the ExpressPCB files to my web site. PCB layout: www.karinya.net/g3txq/corsair_display/Corsair%20display.pcb Schematic: www.karinya.net/g3txq/corsair_display/Corsair%20display.sch 73, S
Mike, It's a proprietary ExpressPCB format and I know of no easy way to convert to a Gerber file. ExpressPCB will do a conversion for you ...... at a price ! Steve G3TXQ If i remember correctly, thos
Jim, I'm surprised you feel so strongly! Throughout your RFI tutorial I see many references to the term "current balun". In a couple of places you put the term in parenthesis, or explain that it is r
These are the input figures I measure for various S-meter readings on my Corsair II 160m: S6 = -90dBm, S9 = -68dBm (89uV), S9+20 = -47dBm 80m: S6 = -90dBm, S9 = -70dBm (71uVuV), S9+20 = -48dBm 40m: S
One option I don't see mentioned often is an electrically short vertical - say 40ft - top loaded with a remotely tuneable mobile whip. The whip adds the required top capacity without introducing the
Rick, That's correct! The only published article I know of was by Tim Forrester G4WIM in RSGB's RadCom - later included in their book "HF Antenna Collection". In addition to the basic top-loading pri
Rick, The original article was in Radio Communication November 1986. The mechanical tuning mechanism was not for the faint-hearted :) but if you already have a spare screwdriver antenna it's a good o
Rick, I deliberately aimed for a slightly high resonant frequency - from memory it was around 2.2MHz. Then I put a small loading coil at the base to pull it onto frequency; that coil had a couple of
Actually, Rrad is less that of the 0.075 wavelength vertical section because you've ignored the opposing currents in the radial "hat" wires. With 16 buried radials - averaging 30ft to 40ft long - the
Interestingly, when using *short* lengths of coax the loss can be lower at high SWR than when it's matched. For example, 10ft of RG213 has a matched loss at 1.9MHz of 0.03dB; but terminated with 500
Sure it does! The losses in feedline at HF are overwhelming due to I^2R copper losses. If you look at the current distribution along a matched line it's flat; for example, flowing 50W into a matched
Correct! In the example I gave, had the 10:1 SWR been caused by a 5 Ohm load rather than a 500 Ohm load, the current would have been a maximum at the load (3.16A) and the loss/unit length at that poi
True - but in the situation being discussed the high SWR on the short length of coax is being caused by the load at the balun/ladderline. Arguably that high SWR is more likely to be a high impedance
I agree! But it's worth noting that the gain of a beam, referenced to a dipole at the same height, varies with take-off angle; so how much louder you will be on your beam compared to a dipole in exac
Rick, Doesn't that halve the CM impedance? Steve G3TXQ If you have a 4:1 Current Balun, then you can easily re-wire it as a 1:1 current balun. You just swap two connections inside. IN FACT... if you