15 Meters is Open

[Traveling Wave]

!5 Meters has been open from 1430 UTC too 2100 UTC for the last few weeks. Stations in Italy, Belgium,South Africa, Poland, Norway, Germany are the usual phone contacts.

[Elf36]

I need to get an antenna set-up for 15M. For some reason my FT-950 will not tune 15 or 30 meters anymore, using an 135' OCF dipole. I really miss having those bands. Especially since 15M is getting better and better.

[RobRich]

The FT-950 is okay for up to ~3:1 SWR into a purely resistive load.

Depending upon the balun and exact feedpoint, your 135' OCF is probably around 3.5:1 to 5:1 on 15m, while 30m could be twice or more that. If the internal tuner was tuning previously either band, I would suspect (up to considerable) losses in the balun and/or feedline masking the mismatch.

You are looking at an outboard tuner for those bands with your OCF, or maybe an autotuner "extender" like the MFJ-914 if you want to ballpark a match workable with the radio's internal tuner.

With room for such a large horizontal dipole, you might would fair better with a doublet and balanced feed line, though you would need an outboard tuner there as well.

[RobRich]

BTW, thought about a vertical wire for chasing 15m DX? An end-fed halfwave dipole would be about 24.6'. Use a 49:1 or 64:1 transformer at the base. The RF ground side, which is going to carry almost no current on an EFHW vertical, could be like just four 6'-12' on-ground radials.

You could add a second half-wavelength wire as a vertical or inverted-L for 30m, too. Basically a fan vertical.

[Elf36]

Yes. I checked the transformer for any water intrusion and replaced the coax with a brand new RG-213. I do have a have an LDG Auto tuner I could hook up and try out.

[RobRich]

I was thinking it was you that mentioned checking a balun and replacing coax, which apparently was a very good decision. I can about imagine the losses if an onboard tuner was easily loading an 80m OCF on 30m through the previous coax. ;)

Not sure what model you have, but even a basic LDG Z-100A will handle 4-800 ohms, so potentially up to 16:1.... complex impedances aside. I suspect that model or similar should handle 15m for your 80m OCF easily enough. 30m might be doable as well, though a good chunk of power might be dissipating as heat, too.

[Elf36]

Yeah, I have an LDG Z-11 Pro2. I'll try it out when I have the time.

[Elf36]

I have an old fiberglass collapsable measuring stick that I painted black. It would be good to use for a 15/20M vertical. I just gotta figure out where to install it.