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Author Topic: Best MWDX antenna?  (Read 53628 times)

Offline ~SIGINT~

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Re: Best MWDX antenna?
« Reply #165 on: June 10, 2022, 0233 UTC »
I just finished relocating 800 km North of my previous QTH so my antenna farm and radio room will be in "rebuild" mode over the next few months and over the summer. All I currently have active is one mini-whip antenna hanging indoors in a patio door connected to my Icom. More to follow ...

Offline RobRich

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Re: Best MWDX antenna?
« Reply #166 on: June 12, 2022, 0814 UTC »
Hudson Bay area, perhaps?



I am dealing with a moderate noise issue apparently from a local temporary power drop to a couple of nearby houses under construction. Suppose I will ignore it for now, at least until the houses are finished. Afterwards if it still persists, then time to contact the power company.

Thankfully is a not powerful broadband RFI, and it seems mostly limited to around 7-9MHz, though that could just be my 31' antenna at play. I can null it even with just a passive YouLoop antenna, so I am thinking about deploying a small active loop antenna for the affected spectrum in the meantime. I have a modified MLA-30 that should suffice, if/when I get around to it.

I have considered a W6LVP or similar active loop.... or maybe building a rotatable HF delta loop, kind of like the models EAntenna offers, but more affordably with poles and wire instead of tubing. It would be a vertical delta loop at mid- to upper-HF, and conversely, a small receiving loop at low-HF and below. Anyway, just kicking around a few ideas for now.
Tampa, FL USA | US Map Grid EL88
Airspy HF+ Discovery | KiwiSDR 2 | 2x Msi2500 Msi001 | 2x RTL-SDR V3 + NE602 | 2x RTL-SDR V4
148' + 60' Loops-on-Ground | 31' Vertical | 18' End-Fed Vertical | PA0NHC MiniWhip

Offline ~SIGINT~

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Re: Best MWDX antenna?
« Reply #167 on: June 15, 2022, 1347 UTC »
Hudson Bay area, perhaps?

Almost, Grid: FN08, Elevation: 275 Meters (902.23 Feet)

I temporarily put up my end-fed longwire last night connected to the ICOM IC-705. Propagation is poor this morning and the bands have been very quiet. Bonus, so far, no more urban / city RFI to deal with. WWVH on 10 MHz has been coming in strong most morning on the mini-whip and ICOM IC-R75.

Offline RobRich

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Re: Best MWDX antenna?
« Reply #168 on: June 16, 2022, 1557 UTC »
Congrats on the low RFI situation.

My local noise floor is surprisingly decent most of the time, especially for a neighborhood. Just happens every few years something seems to pop up. Thankfully the power company has been good to respond when it was their issue(s).

Picked up parts to build a basic freestanding inverted vertical delta loop.  I am targeting about a 36' perimeter so it should resonate in the 11m band, assuming I ever bother using it for transmitting. Otherwise it still should be small enough to have some directivity as a receiving loop on lower HF bands, thus hopefully mitigating that annoying RFI until those nearby houses are completed and the temp power drop replaced with a permanent one.

Now to actually get around to building the antenna.... ;)
Tampa, FL USA | US Map Grid EL88
Airspy HF+ Discovery | KiwiSDR 2 | 2x Msi2500 Msi001 | 2x RTL-SDR V3 + NE602 | 2x RTL-SDR V4
148' + 60' Loops-on-Ground | 31' Vertical | 18' End-Fed Vertical | PA0NHC MiniWhip

Offline ~SIGINT~

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Re: Best MWDX antenna?
« Reply #169 on: June 17, 2022, 0101 UTC »
Just got the RSPduo connected back up to the end-fed longwire. I am running at about -120 dBm for the noise floor. The antenna is currently not at optimum. 42 ft of wire about 8 ft or so off the ground terminated in a Palomar Engineers end-fed bullet transformer. At least I am on the air and can look forward to see how the pirates will perform.




Update: 01:04 UTC 17 June 2022 - CHIL World Radio on 6925.0 kHz is making it up this way with a good signal. The noise floor on this portion of the band is at -110 dBm.
« Last Edit: June 17, 2022, 1337 UTC by ~SIGINT~ »

Offline Ray Lalleu

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Re: Best MWDX antenna?
« Reply #170 on: June 17, 2022, 1106 UTC »
Congrats on the low RFI situation.

Picked up parts to build a basic freestanding inverted vertical delta loop.  I am targeting about a 36' perimeter so it should resonate in the 11m band, assuming I ever bother using it for transmitting. Otherwise it still should be small enough to have some directivity as a receiving loop on lower HF bands, thus hopefully mitigating that annoying RFI until those nearby houses are completed and the temp power drop replaced with a permanent one.

Now to actually get around to building the antenna.... ;)
Could be not so good, with the loop being a 'top hat' on the line acting as an antenna (in common mode or outside of the coax). So try to cut the loop in the exact middle, with the line in the middle plane, to make things as symetrical as possible. An ATU could help, otherwise use the high-Z antenna input.
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Offline RobRich

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Re: Best MWDX antenna?
« Reply #171 on: June 17, 2022, 1553 UTC »
The basic design idea:

http://www.eantenna.es/?page_id=2571

I agree inverted delta loops ideally should be symmetrical with adequate common-mode mitigation when fed at the base. Otherwise the primary concern is the takeoff angle tends to go high if fed at the base, especially as frequency increases above resonance. I am targeting upper HF with the design, so conversely it should start resembling a small receiving loop as frequency drops to low HF and lower anyway.

BTW, the only place I might use it for transmitting would be 11m, though that would be secondary at best as I already have half-wave verticals for DX on that band.
Tampa, FL USA | US Map Grid EL88
Airspy HF+ Discovery | KiwiSDR 2 | 2x Msi2500 Msi001 | 2x RTL-SDR V3 + NE602 | 2x RTL-SDR V4
148' + 60' Loops-on-Ground | 31' Vertical | 18' End-Fed Vertical | PA0NHC MiniWhip

Offline RobRich

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Re: Best MWDX antenna?
« Reply #172 on: September 29, 2022, 2023 UTC »
Still not built the vertical loop, or done much with radios for a few months now.

Hooked up the 31' vertical, built a recent SDRangel checkout, and turned on the Airspy HF+D while the hurricane has been moving through FL. Thankfully my area was largely spared.

Need to check on the antenna farm. Not from wind or anything, but more because it has been mostly out of use over the summer. Probably need to fix a few ground radials and similar maintenance.

Still thinking about deploying a small 11m beam like the Maco V-Quad. Some upper HF directivity would be nice for European DX and similar.

On a positive note, my lower HF noise condition is much improved. AFAICT, those two new nearby houses are complete, and the temporary power drop is not in use. The electric company still needs to do the permanent drops, but the other nearby residential drops in the neighborhood largely behave, so hopefully those will play nice as well.
« Last Edit: September 29, 2022, 2220 UTC by RobRich »
Tampa, FL USA | US Map Grid EL88
Airspy HF+ Discovery | KiwiSDR 2 | 2x Msi2500 Msi001 | 2x RTL-SDR V3 + NE602 | 2x RTL-SDR V4
148' + 60' Loops-on-Ground | 31' Vertical | 18' End-Fed Vertical | PA0NHC MiniWhip

Offline East Troy Don

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Re: Best MWDX antenna?
« Reply #173 on: September 29, 2022, 2132 UTC »
Glad to hear you dodged the IAN bullet, Rob.   I used to live in Destin - I know the feeling.
Primary: Yaesu FRG-7700  Secondary: ICOM R75 Tertiary: Grundig  750. Tecsun PL-990X, Tecsun PL-880 . Malahit DSP SDR V3,  Alpha Delta  SWL Sloper antenna. : Also, 1940 Mantola am/sw tube. CountyComm GP-5/SSB hand held, Tecsun PL-380 ,et al.  QTH: EAST TROY WI  USA.  Sea Level: + 320 meters .  75 miles (but not far enough) NNW of Chicago

Offline RobRich

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Re: Best MWDX antenna?
« Reply #174 on: September 29, 2022, 2217 UTC »
Thanks for the positive thoughts.

I dropped Elf36 a PM. He is in the Orlando area. Hoping he and his family are okay.
Tampa, FL USA | US Map Grid EL88
Airspy HF+ Discovery | KiwiSDR 2 | 2x Msi2500 Msi001 | 2x RTL-SDR V3 + NE602 | 2x RTL-SDR V4
148' + 60' Loops-on-Ground | 31' Vertical | 18' End-Fed Vertical | PA0NHC MiniWhip

Offline RobRich

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Re: Best MWDX antenna?
« Reply #175 on: September 30, 2022, 0041 UTC »
Elf36 replied a few minutes ago. Thankfully he and his family are okay.
Tampa, FL USA | US Map Grid EL88
Airspy HF+ Discovery | KiwiSDR 2 | 2x Msi2500 Msi001 | 2x RTL-SDR V3 + NE602 | 2x RTL-SDR V4
148' + 60' Loops-on-Ground | 31' Vertical | 18' End-Fed Vertical | PA0NHC MiniWhip

Offline ~SIGINT~

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Re: Best MWDX antenna?
« Reply #176 on: September 30, 2022, 0109 UTC »
I believe Outhouse Radio is out Florida way as well --- but don't quote me on that.

Offline RobRich

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Re: Best MWDX antenna?
« Reply #177 on: October 21, 2022, 2022 UTC »
Swapped around a couple of outside connections for testing. Could be both my active antennas are either cooked and/or have feedline problems. Need to break out a meter later to check them later. Fun stuff.

Hopefully my 18' 10m/11m vertical should be okay other maybe fixing a couple of ground radials radials..

Kind of curious to see if my 148' LoG is still okay.

FWIW, I have been relying upon my 31' vertical for basically all HF and lower bands for quite awhile now.

I probably should be looking at replacing multiple feed lines, along with eventually installing a remote antenna switch I have collecting dust on a shelf.
Tampa, FL USA | US Map Grid EL88
Airspy HF+ Discovery | KiwiSDR 2 | 2x Msi2500 Msi001 | 2x RTL-SDR V3 + NE602 | 2x RTL-SDR V4
148' + 60' Loops-on-Ground | 31' Vertical | 18' End-Fed Vertical | PA0NHC MiniWhip

Offline RobRich

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Re: Best MWDX antenna?
« Reply #178 on: October 22, 2022, 0733 UTC »
Both active antennas appear cooked. Ground radials on the 18' vertical cut. A couple of cut feedlines. Pulled up a few runs of old RG-6 coax while taking a look.

Hoping to check the 148' LoG and fix the 18' vertical ground radials over the weekend.

Thinking I might still have a spare active antenna board of the same model as those previously deployed. Perhaps a quick fix for one of them.

I am pretty sure there is a generic eBay clone of an active antenna in my parts. The enclosure is probably sealed knowing my luck, thus no idea on what design it actually is. I suppose "whatever" assuming it works.

Also I do know there is a MLA-30 in parts storage that I modified but never actually deployed. Not a great antenna, but I might toss it up in the meantime anyway.

Otherwise, it could be time to seriously consider revamping part of the antenna farm. Near the top of the list is improving feedlines on my receiving antennas. Maybe direct-bury RG-11.
Tampa, FL USA | US Map Grid EL88
Airspy HF+ Discovery | KiwiSDR 2 | 2x Msi2500 Msi001 | 2x RTL-SDR V3 + NE602 | 2x RTL-SDR V4
148' + 60' Loops-on-Ground | 31' Vertical | 18' End-Fed Vertical | PA0NHC MiniWhip

Offline ~SIGINT~

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Re: Best MWDX antenna?
« Reply #179 on: October 22, 2022, 1246 UTC »
Rob, you sure have had a run of bad luck with your antennae farm.

Have a look here for another "mini-whip" kit.

VE3FEX amplified antenna kit:
http://www.ontars.com/cgi-bin/classifieds/classifieds.cgi?session_key=&search_and_display_db_button=on&db_id=4337&query=retrieval

and

https://ontars.com/whip_kit/index.html

I wish I would have known about this kit before importing "clones" from overseas. It appears to be well built. There is also a review by VE3CV on the same page. It might be something worth considering.

 

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