This is an amateur topic, so there's no reason to take it offline, imho. If you run the impedance vs spacing calculations, you'll see the spacing doesn't make a whale of a lot of difference. I don't have the numbers here, but I switched from 1/2 of a BIC pen body (hole centers about 2" apart) to some ceramic spacers another ham gave me a box full of. The new spacers had centers about 3.2" apart. I had to re-tune the ATU on most bands, but everything continued to work fine. From (a tired old) memory, the impedance varied from about 450 ohms to something like 600 ohms, but let someone on a computer run the calcs for this. It just didn't make enough difference to worry about, but did change the ladder feed's impedance.
This antenna is a doublet about 180' long at 45 feet height, fed with the ladder line (61' of it, from memory). The ladder line terminates into a 1:1 balun (Elecraft BL2) and the last 20 feet is LMR400 low-loss coax back to the station's antenna switch. It continues to work just as well as with the earlier ladder spacers. 73, matt W6NIA On 04/15/2017 09:39 AM, Richard Fjeld wrote: > Forgive me for the OT, but there are many antenna people here above my > pay-grade. > > I need to replace the spacers on my ladder line. If I deviate from the > standard spacer length for impedance > (separation between conductors), are there problems I'm not thinking > of? I use a quality manual tuner, and > an 80 meter delta loop. > > Perhaps it would be best to reply off line for this. Thank you in advance. > > Dick, n0ce > -- "Always store beer in a dark place." -- R. Heinlein Matt Zilmer, W6NIA [Voignier] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
