We seek to understand and document all radio transmissions, legal and otherwise, as part of the radio listening hobby. We do not encourage any radio operations contrary to regulations. Always consult with the appropriate authorities if you have questions concerning what is permissable in your locale.

Author Topic: Inverted sloper?  (Read 383 times)

Offline TheDelman

  • Newbie
  • *
  • Posts: 8
    • View Profile
Inverted sloper?
« on: September 04, 2019, 2112 UTC »
Hi all, just joined, hope won't hold that against me... :)..

Anyway... bought off ebay a 40 meter wide dipole 1/2 wave, so over 66 ft long antenna..
Great I thought, arrived and then I thought, hang on, which end do I hang it...

contacted the seller, who offered couple weird like suggestions, nothing easy, well one wasn't weird, was using a meter, which not have that sort to try and figure it out, not keen to break it apart either, as well made, not like ones I have often done, lol.

My question is this:
Does it matter, if as connects Via the pl259 plug, if main element that comes from inner core coax cable ends up, upside down..
Sorry not good with words..

Pretend I'm putting it up as a vertical, inner core cable goes to upper half and outer braiding goes to lower, often refered to as ground plane, not sure on half wave dipole if called a ground plane.. Anyway what if it's upside down...

I could do inverted V but be like 65 ft up and given only have 100 feet cable and distance likely from that height end up more... I know, tricky situation and google searches suggest sloper often better picking up weaker further away stations than inverted V anyway... taking say hundreds miles to 1000, not up to few hundred miles away say...

I could, but a pain, hang it and try it, listening to voice clock thing on 5,000 mhz and 10,000 mhz, then turn around, just time consuming and a pain, lowering back down and changing over and hanging the other end...

Sorry so long, always was a long talker, lol... appreciated, if read this far... :)..
« Last Edit: September 07, 2019, 0159 UTC by ChrisSmolinski »

Offline radiogaga

  • Full Member
  • ***
  • Posts: 236
    • View Profile
Re: Inverted sloper?
« Reply #1 on: September 05, 2019, 1505 UTC »
If antenna only has center insulator and not balun you would like center conductor at the top if hung vertical. If there is 1:1 balun there is no mechanical connection and thus no up or down.
Remember if hung vertical, your noise level will be higher due to noise being vertical polarized also.
If you don't have an ohmmeter a small battery can be used to determine by placing one side of battery to pl259 center, touch each far end of antenna to other side of battery. The one that shows a small spark or two will be your center conductor element.
Have fun.... and welcome

Offline Josh

  • DX Legend
  • ******
  • Posts: 3448
    • View Profile
Re: Inverted sloper?
« Reply #2 on: September 05, 2019, 1809 UTC »
I have a few 1:1 baylums that pass dc at all terminals.
For the most part, wich way is up is typically irrelevant to an hf dipole. For rx only I wouldn't worry about this at all..
Conveniently located near Vincennes Indiana.

Offline Pigmeat

  • DX Legend
  • ******
  • Posts: 4305
    • View Profile
Re: Inverted sloper?
« Reply #3 on: September 05, 2019, 2038 UTC »
Slopers aren't as affected by noise as verticals and they do pick up weak signals well before inverted V's. If you've got one high support it's an easy up antenna with a lot going for it. They're directional to signals coming from where the low end is pointed, giving the listener the option to hang a few from a single high spot in the directions they want to listen in. Plus, they clothesline common pests, like deer and kids.

A fine antenna all the way around.

Offline TheDelman

  • Newbie
  • *
  • Posts: 8
    • View Profile
Re: Inverted sloper?
« Reply #4 on: September 05, 2019, 2047 UTC »
Hmm... thanks for reply guys.... still not sure got what I was quite after lol...

Anyway... yes sloper, i had one made, mostly made them, came down cause of the cord, I knew about that one cause I made it, this one I bought off ebay, not sure allowed to link here, notmally just do it anyway, but trying to be good so, lol..
Radioman79 think it is, blue wire, mine came grey, 40 meters... dipole, those plastic housing with connection at bottom for pl259..

But I do not know which is main element... for listening, not transmitting, but even so, would have liked to have had the inner core of cable one go to the wire at the top... gosh hard to explain, and I never was good with words, which is why i mentioned hanging it vertical as an example, was planning on having it slope, and yes I know will pick up mainly better in one direction that is fine..

LET'S put it this way then, and this is pretend only:
Remember this is not my set up, pretend:

Hi guys, made a 40 meter dipole, joined in middle by cable, only I decided to attach the inner core cable to the bottom run of it and the outta braid to the top part from the tree about 67 feet up (height part is about true, over 60 feet high in pint tree) I was wondering if this will still pick up long distance DX or should I have connected the inner core of the cable, rg6 to the top part of the diople..

Hope that explains it better, it's 40 meter, 7mhz, but I'm interesting in listening only, no rig, no transmit, on a gp5 think it is, small thing, can pick up side band etc.. it's a county comm small thing.. 

Offline ChrisSmolinski

  • Administrator
  • Marconi Class DXer
  • *****
  • Posts: 23921
  • Westminster, MD USA
    • View Profile
    • Black Cat Systems
Re: Inverted sloper?
« Reply #5 on: September 05, 2019, 2155 UTC »
LET'S put it this way then, and this is pretend only:
Remember this is not my set up, pretend:

Hi guys, made a 40 meter dipole, joined in middle by cable, only I decided to attach the inner core cable to the bottom run of it and the outta braid to the top part from the tree about 67 feet up (height part is about true, over 60 feet high in pint tree) I was wondering if this will still pick up long distance DX or should I have connected the inner core of the cable, rg6 to the top part of the diople..

Hope that explains it better, it's 40 meter, 7mhz, but I'm interesting in listening only, no rig, no transmit, on a gp5 think it is, small thing, can pick up side band etc.. it's a county comm small thing..

In general, it doesn't matter which end of the dipole you connect to the shield and center connector of the coax. Just to be clear, your dipole should be *two* pieces of wire, one to each conductor of the coax.

In practice, you should use a balun to connect coax to a dipole, vs just directly connecting to the two elements. It's better for a receive only antenna, and much better for an antenna used for transmitting. Even though you're certainly using it for listening only  ;D
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
NRD 545 / netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 670 ft horizontal loop / 500 ft northeast beverage / 58 ft T2FD / 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop

Offline TheDelman

  • Newbie
  • *
  • Posts: 8
    • View Profile
Re: Inverted sloper?
« Reply #6 on: September 06, 2019, 1605 UTC »
ChrisSmolinski:
Yes, has balun, but I'm going to use rg6 cable... Anyway... on ebay by radioman79 40 meter, yes wire sort connected in one of those plastic things, so, think so239, so connected by pl259... didn't indicate which was main element, the part that the inner core of cable, sold, or stranded bit connects to and the out braiding of cable connects to...
Was just wanting to avoid all the trouble (depends how I feel at the time) of trying to hang it vertical, try on 5.000 mhz and 10.000 mhz for clock thing... and then seeing if it was better one way around or other..
Means connecting, pulling up and testing that way, then lowering, changing around, sounds simple doesn't it and it might be but with over 66feet long wire, just a pain is all..
If makes no difference if main element is at bottom then cool..

Reminder: ebay.com/itm/40-meter-40M-Half-Wave-Amateur-Ham-Radio-Dipole-Antenna/123704499735

40 meter (40M) Half-Wave Amateur Ham Radio Dipole Antenna

So now you know, removed the http and www part ok...

Anyway can not thank you enough for replies..

It will be about 60 to 70 ft high, well height the wires that can hold it at, of course as a sloper mean 33 feet odd lower as slopes down from pine tree...

My home made one, likely lower and picked up this guy in South Africa every night in 7.000 mhz that liked with his huge beam to give people a chance in the USA to see if they could reach him..
Sadly used white cord from Walmart, eventually after many months wore out it seems and came down... thought treat myself to a proper made one, intstead of my often ok, but not great jobs... :)..

Offline Exo

  • Full Member
  • ***
  • Posts: 189
  • Coast of northern California
  • HF aficionado.
    • View Profile
Re: Inverted sloper?
« Reply #7 on: September 06, 2019, 1634 UTC »
Put the feedpoint up as high as possible.
If one end is higher, make it the "hot" side.
Exo
HF aficionado. On the coast of northern California.
Various receivers, transceivers, and broadband antennas.
kiwiSDR receiver on private LAN for multi-freq HF monitoring.

Offline ChrisSmolinski

  • Administrator
  • Marconi Class DXer
  • *****
  • Posts: 23921
  • Westminster, MD USA
    • View Profile
    • Black Cat Systems
Re: Inverted sloper?
« Reply #8 on: September 06, 2019, 1657 UTC »
ChrisSmolinski:
Yes, has balun, but I'm going to use rg6 cable... Anyway... on ebay by radioman79 40 meter, yes wire sort connected in one of those plastic things, so, think so239, so connected by pl259... didn't indicate which was main element, the part that the inner core of cable, sold, or stranded bit connects to and the out braiding of cable connects to...

Reminder: ebay.com/itm/40-meter-40M-Half-Wave-Amateur-Ham-Radio-Dipole-Antenna/123704499735

From the eBay description, and based on the price, I suspect the PVC center is NOT a balun, and instead each element of the antenna is connected directly to the UHF connector. That does not mean it won't work at all, but it may not work as well as with a balun.
Chris Smolinski
Westminster, MD
eQSLs appreciated! csmolinski@blackcatsystems.com
NRD 545 / netSDR / AFE822x / AirSpy HF+ / KiwiSDR / 670 ft horizontal loop / 500 ft northeast beverage / 58 ft T2FD / 300 ft south beverage / 43m / 20m / 10m  dipoles / Crossed Parallel Loop

Offline Josh

  • DX Legend
  • ******
  • Posts: 3448
    • View Profile
Re: Inverted sloper?
« Reply #9 on: September 06, 2019, 1750 UTC »
Center conductor = wire in middle of coax

Shield = braid/solid shield around center conductor

If you want the center conductor connected to the upper part of the antenna, get your dmm out and start checking wich wire is connected to the center pin of the coax connector. If you can't get to bare wire, use a needle to pierce the insulation to get a reading.
Conveniently located near Vincennes Indiana.

Offline TheDelman

  • Newbie
  • *
  • Posts: 8
    • View Profile
Re: Inverted sloper?
« Reply #10 on: September 06, 2019, 1931 UTC »
so Josh, assume, as not know what dmm is mean a meter, so now gonna cost me more money still, gosh... but think you mean one of those meters that, hmm, yeah I get it, ok, one, how can i explain, makes a noise or should do when you touch one think, side, wire, connected to other wide.. so take the cable off with the pl250 plug on, right, put meter, what call them, connecter wire from meter one end in middle of the S0239, whatever female thing called that pl259 goes in, and then the other end of meter connected wire on one of the long 33 feet plus wires, if makes a noise that's the inner upper end should hang from tree... KK, think that's what radioman was suggesting, i have meter, not sure have that function on, and ruined it once, so not read correctly, however, it might, hmm, might be a setting, or, oh oh, HANG on, lol, what about, could use not sure how yet a battery through the wire, hmm, anyway thanks, least, Josh (Thanks to every one for input though, appreciated) but Josh least now given me idea on maybe how i can find out... thanks :)..
I'll go experiment with a short piece of wire and see what meter reads on settings, if anything touching one end of wire, might be bare copper wire, one end to other, if nothing, and I have no noice one on it, as cheap thing from walmart years back, I'll erm, maybe think about how can connect so reads a battery through it, only work if I get right wire, inner core one i want... :)

Offline TheDelman

  • Newbie
  • *
  • Posts: 8
    • View Profile
Re: Inverted sloper?
« Reply #11 on: September 06, 2019, 1939 UTC »
actually just realized and duh, just need to touch meter connectors together, the red and black...

FURTHER: (By the way u use Caps to stand out to make a point, please take note kind of thing, not shouting lol)

So i have what I think is ohms setting look kinda like headphones and if i put this on 200 the meter changes from 1    .
to
0.04 once settled, when first touch it, reads 0.21 say oh or 63. something, so varies, but fact settles down, means showing something and did through the wire also, no let me try wire and then meter connector on something totally different, metal wise say..
Yay obviously nothing, but had to do it, now gonna go try antenna..

Offline TheDelman

  • Newbie
  • *
  • Posts: 8
    • View Profile
Re: Inverted sloper?
« Reply #12 on: September 06, 2019, 1947 UTC »
YAY one it worked, once and was in direction i would tried and put it up first anyway, once established this, noticed the slight sticking out bits of plastic on top above one wire and on the bottom below other wire, LOL duh... well I didn't know, no one said, come on now, none of you said well should be marked surely... but silly me... anyway YAY thanks every one so so so much, thanks to Josh also for giving me idea of my meter...
Weird that, not an electrician, not that smart, but weird bare wire, reading slight ohms. oh hang on, so maybe they do, no power needed, wonder if 50 ohm cable just reads that, hmm, anyway whatever...
Case closed..

Offline Josh

  • DX Legend
  • ******
  • Posts: 3448
    • View Profile
Re: Inverted sloper?
« Reply #13 on: September 06, 2019, 2029 UTC »
Well done!
Conveniently located near Vincennes Indiana.

Offline TheDelman

  • Newbie
  • *
  • Posts: 8
    • View Profile
Re: Inverted sloper?
« Reply #14 on: September 06, 2019, 2143 UTC »
Thanks Josh...most kind... (I'm from UK originally) lucky where I am, lots tall pine trees like... Well I shall lock this myself if allows me, thanks all for reading, appreciated... let's hope this goes on alright and is as good as one i made and had up that allowed me to head that guy on his beam in South Africa over 10,300 miles away like... :).