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Author Topic: 15 Meters is Open  (Read 263 times)

Offline Traveling Wave

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15 Meters is Open
« on: October 09, 2021, 1621 UTC »
!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.
« Last Edit: October 09, 2021, 1639 UTC by Traveling Wave »
Location: Western New York ( Niagara Frontier)
Radio :TS480 with RTL-SDR pan-adapter, HDSDR, Omni-Rig Control, Zenith T/O R600,T600
Antenna: 40m dipole, 20-17-15 meter fan dipole. One of N. Tesla's own prototypes. A high-powered mutant of some kind never even considered for mass production.
eQSL appreciated

Offline Elf36

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Re: 15 Meters is Open
« Reply #1 on: October 14, 2021, 1639 UTC »
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.
Yaesu FT-950, 135' OCF dipole @ 28', SignaLink interface, Vibroplex Square Racer paddle. RSP2 SDR with an OCF antenna and a Grundig G3 for portable.

Offline RobRich

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Re: 15 Meters is Open
« Reply #2 on: October 14, 2021, 2103 UTC »
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.
Tampa, FL USA | US Map Grid EL88
Airspy HF+ Discovery | Kenwood R-600 + R-2000 | 2x RTL-SDR V3 + NE602 | Si-Tex 200 | Soft66LC4 | Yaesu FRG-7
148' "Shielded" Loop-on-Ground | 18' End-Fed Vertical | 9' + 31' Verticals | 2x PA0NHC MiniWhips

Offline RobRich

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Re: 15 Meters is Open
« Reply #3 on: October 14, 2021, 2112 UTC »
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.
« Last Edit: October 14, 2021, 2115 UTC by RobRich »
Tampa, FL USA | US Map Grid EL88
Airspy HF+ Discovery | Kenwood R-600 + R-2000 | 2x RTL-SDR V3 + NE602 | Si-Tex 200 | Soft66LC4 | Yaesu FRG-7
148' "Shielded" Loop-on-Ground | 18' End-Fed Vertical | 9' + 31' Verticals | 2x PA0NHC MiniWhips

Offline Elf36

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Re: 15 Meters is Open
« Reply #4 on: October 15, 2021, 1337 UTC »
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.
Yaesu FT-950, 135' OCF dipole @ 28', SignaLink interface, Vibroplex Square Racer paddle. RSP2 SDR with an OCF antenna and a Grundig G3 for portable.

Offline RobRich

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Re: 15 Meters is Open
« Reply #5 on: October 15, 2021, 1957 UTC »
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.
Tampa, FL USA | US Map Grid EL88
Airspy HF+ Discovery | Kenwood R-600 + R-2000 | 2x RTL-SDR V3 + NE602 | Si-Tex 200 | Soft66LC4 | Yaesu FRG-7
148' "Shielded" Loop-on-Ground | 18' End-Fed Vertical | 9' + 31' Verticals | 2x PA0NHC MiniWhips

Offline Elf36

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Re: 15 Meters is Open
« Reply #6 on: October 15, 2021, 2231 UTC »
Yeah, I have an LDG Z-11 Pro2. I'll try it out when I have the time.
Yaesu FT-950, 135' OCF dipole @ 28', SignaLink interface, Vibroplex Square Racer paddle. RSP2 SDR with an OCF antenna and a Grundig G3 for portable.

Offline Elf36

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Re: 15 Meters is Open
« Reply #7 on: October 17, 2021, 1133 UTC »
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.
Yaesu FT-950, 135' OCF dipole @ 28', SignaLink interface, Vibroplex Square Racer paddle. RSP2 SDR with an OCF antenna and a Grundig G3 for portable.