We must both be attracted to threads with the word skanks.
Scanking TXHF-6 discone for attic?
- Thread starter va2fsh
- Start date
I think you will be much happier with an outside antenna like an EFHW, it would be almost impossible to get something in an attic to work that well. Are you looking at a 64ft 40m version or a 133ft 80m version?
I ordered a 64:1 balun, a tuner and 135ft of wire (I should have enough room with a 45 degree bend out to 100ft approx).
Canada Post is in lockout at the moment though. The tuner is stuck in a CP warehouse while the rest of the things I need are trickling in so all the other carriers are picking up more work (on top of it being the holiday season).
I' going to try going through the window with a rg213 8" jumper...going to see how that goes.
Canada Post is in lockout at the moment though. The tuner is stuck in a CP warehouse while the rest of the things I need are trickling in so all the other carriers are picking up more work (on top of it being the holiday season).
I' going to try going through the window with a rg213 8" jumper...going to see how that goes.
A 133ft 80-10m EFHW when tuned for 40, 20, etc, will resonate on the low end of 80m like around 3.55MHz with high VSWR in the phone portion of 75m. There is a mod to place a HV, high current capacitor in the middle of the wire which will raise the 80m frequency to about 3.9MHz with a good match from 3.8 to 4.0Mhz for 75m phone. I have the specs around here somewhere and you can get an appropriate HV doorknob cap off ebay cheap.
Looking over some notes from Danny at MyAntennas, when making your 80m EFHW make a coil of wire 5 turns around a 2" OD form 78" out from the 64:1 transformer. This helps with matching somewhere. There is a grey PVC conduit junction that is exactly 2"OD and you can drill a hole at each end of the junction to pass the wire through the inside, wrap the windings then exit down through the hole on the opposite side so it will become a strain relief. Then cut the antenna in half 67ft from the far end insulator and insert another insulator then bridge that with a 150pf 10-15kV doorknob cap or similar. There are some HV disc caps that are useable and MyAntennas uses two in series for better HV rating.
It's a Christmas miracle! hehe Canada Post has delivered my tuner (strike's over) and I have found some stealth wire locally (22 AWG: I know, it's going to be too small and might get knocked by the wind).
I measured about 66-67ft of antenna wire and installed everything yesterday from the second story of the house, all the way to some trees in my backyard. It gets dark at 16h30 here, so I did all of this as best as I could yesterday. It's only about 10' off the ground. I will try to get it higher up today or this weekend when I get a chance.
I tried tuning the antenna and I got an SWR of 1.04-1.06 on 7.200Mhz at around 21h00'ish. I think (I tried a few frequencies). Sounds very decent. But I tried listening to my transmission through a KiwiSDR station approx. 300km away. The remote station heard absolutely nothing ;-( I tried with another station a bit further out (few hundred km's further). Still nothing. While transmitting, my SWR varied but stayed below 1.8 (otherwise, the tuner would of jumped in and automatically retuned), might of even been below 1.5.
I'm unsure how to further test and debug my antenna.
As I scanned the band, I could hear a few stations here and there. Some in languages I couldn't even Identify. So...I figure I can receive with it.
A friend has been suggested that I should ground the coax shield, but I've read that EFHW don't need grounding, so I'm a bit confused on that part.
Cheers,
David
I measured about 66-67ft of antenna wire and installed everything yesterday from the second story of the house, all the way to some trees in my backyard. It gets dark at 16h30 here, so I did all of this as best as I could yesterday. It's only about 10' off the ground. I will try to get it higher up today or this weekend when I get a chance.
I tried tuning the antenna and I got an SWR of 1.04-1.06 on 7.200Mhz at around 21h00'ish. I think (I tried a few frequencies). Sounds very decent. But I tried listening to my transmission through a KiwiSDR station approx. 300km away. The remote station heard absolutely nothing ;-( I tried with another station a bit further out (few hundred km's further). Still nothing. While transmitting, my SWR varied but stayed below 1.8 (otherwise, the tuner would of jumped in and automatically retuned), might of even been below 1.5.
I'm unsure how to further test and debug my antenna.
As I scanned the band, I could hear a few stations here and there. Some in languages I couldn't even Identify. So...I figure I can receive with it.
A friend has been suggested that I should ground the coax shield, but I've read that EFHW don't need grounding, so I'm a bit confused on that part.
Cheers,
David
An EFHW doesn't need any grounding to operate, its pretty much self contained. I would recommend a good 1:1 common mode choke on the feedline for when you get near band edges and the SWR goes up, they can put a little RF on the coax when operated out of band. If your local electrical code requires you to ground the coax as it enters the house that's for human safety and nothing to do with antenna performance.
Alright, I see. Good point. Seeing as they are forecasting -20C on Sunday night...I highly doubt we're going to have any lightning anytime soon. Should they forecast bad weather, I'm going to take down the antenna.
David
To see what other stations are hearing you, where they are, and how well they hear you use this website-
Hmm, so my EFHW 40-10 seems to work alright, mostly on 40m. The other bands...I'm getting a high SWR. Which I think is what @prcguy was talking about. I've just seen a video explaining what you were mentionning I believe...from HamRadioDude. I had 3d printed these tiny plastic cylinders to make coils on (10-11 turns on 19mm cylinder). I believe it should shift the low SWR for 20-10m closer to the ham portion of the band.
My question is, could this also work for a 80-10m EFHW?
Cheers and happy new year!
David
My question is, could this also work for a 80-10m EFHW?
Cheers and happy new year!
David
I've built lots of 40m EFHWs with no coil near the transformer and they all worked fine. Maybe 10m resonated a little high but that's about it. When tuning one I balance 40m and 20m to cover the phone portion of the band which turns out around 7.150 on 40m and 14.300 on 20m but it has enough BW to cover all the phone portions with a good match. If your best match on 40m is on the high end like 7.250 that will push 20m up to 14.500 and out of band including higher bands.
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