[600MRG] More 630m antenna efficiency...

Sun Sep 2 11:46:47 EDT 2018

Ike, Gedas, et al,

Wrist rocket fer sure, thumbs up... We have giant tall pines here so 
need compound bow and PVC air rocket is good too...

Even a David vs. goliah sling using fish weight and mono line works 
after several practice tries...

Conditions around here are kinda punk since I got back on but down under 
are doing very well across the earth's solid conductivity salt water 
ground...
Now there is a place for a vertical, plug the ground end in to the ocean 
and 'voila' instant DX... Only one radial needed...

Guy up in Maine on AM 730kcs is a KW day timer on the coast and he gets 
out like gang busters... The 5 KW directionals inland do way worse, just 
sayin...

On 9/2/2018 9:45 AM, Gedas wrote:
>
> IMO the absolute cheapest, accurate, and efficient way to get wires 
> way up high and exactly where you need them is with a "wrist-rocket" 
> type sling shot....sometimes known as a hunting sling-shot.
>
> You can find them on Amazon etc for ~$15 shipped. You can get very 
> fancy with all kinds of other excellent devices but if you want fast 
> and cheap and where ya want it in the tree just get one and be done in 
> no time.
>
> I reel out about 100' of fishing line on the ground in a long zig-zag 
> (back-and-forth) pattern, attach a 1-2 ounce tear-drop shaped fishing 
> sinker to the end of the fishing line, stand off and behind and away 
> from the fishing line on the ground then let-er-rip. Even in areas 
> that have tall grass etc the line on the ground will work fine. Just 
> make sure it is not wrapped around any branches or debris on the 
> ground that will keep the fishing line from being pulled up and into 
> the air.
>
> The sinker will be over the limb you need in 3-4 seconds along with 
> your initial fishing line. If it does not fall to the ground just 
> LEAVE EVERYTHING BE for an hour or so and nature (slight breeze and 
> branch motion) will let gravity slowly drop the sinker to the ground 
> for you.
>
> I then go to the far end of the line that is now on the ground, break 
> off the sinker, and tie on one end of a 300' roll of 1/8" white Nylon 
> twine. You can get 200-300 feet of this stuff for less then 
> $6......pull it up and in place of the fishing line and now you are 
> ready to attach your real Dacron rope etc to the 1/8" Nylon twine. 
> Done in no time with a total of ~$20 spent. And no fear of an arrow 
> breaking free and coming down or through someplace you did not want it 
> to 300' away. At least that's the way I do it here. Been doing it this 
> way for over 45 years and it works 100% of the time for trees up to 
> 80' or so.
>
> Gedas, W8BYA
>
> Gallery athttp://w8bya.com
> Light travels faster than sound....
> This is why some people appear bright until you hear them speak.
> On 9/2/2018 9:21 AM, Dwight Blevins via 600MRG wrote:
>> Dave,
>>
>> Sounds like our situations are similar. Dirt here in western Colorado 
>> is mix of sandstone and ground glass. With about 5 to 6 inches of 
>> precip per annual, might as well forget the verticals, though I do 
>> have one. Couple of 40 ft. tall trees in the back yard, so I'm trying 
>> to figure out how to get a wire up and over without breaking my 72 
>> year old neck.
>>
>> Anybody ever tried casting a fishing line? Probably a bow would work 
>> best, but I've never had to use this sort of thing to get a wire over 
>> a tree top. No way to get a bucket truck back there, so I'm still 
>> scratching my head on how to get my wires up higher, at least on one 
>> or two sides of the loop. After reading all the comments on ground 
>> loss the past couple of days I'm convinced more effort with the 
>> vertical is probably a bad idea.
>>
>> Time is flying by, with only a few weeks to go before 630m fall 
>> activity.
>>
>> Ike, KW7T
>>
>> On Sunday, September 2, 2018, 3:32:34 AM MDT, Dave Riley 
>> <dave.riley3 at verizon.net> wrote:
>>
>>
>> Aye, Pat,
>>
>> The possibilities become endless with new technology but I still 
>> struggle with a self imposed beer budget left over from that great 
>> depression...
>> Mainly because it is cheap, fun, and really taxes my mojo or what is 
>> left of any creative juices...
>>
>> If one is blessed or cursed with high pines trees then nirvana is 
>> either here or gone...
>>
>> A compound bow, air gun, or sling shot is the new and cheaper bucket 
>> truck with dacron rope so strong and cheap that it doesn't even get 
>> recycled...
>>
>> The latest attempt here at cheating nature is to rig wires and feed 
>> till the DX goes up... I'm always harping on groundless antennas cuz 
>> let's face it, that's where most power is lost...
>> Trillions of idle radials can't be wrong...
>> Sixr inch copper strap makes a wunnerful loop for efficiency until 
>> the breeze comes up then the copper goes airbourne and another 
>> disappointment needs to be forgotten...
>>
>> Today's new scientific observations suggest that a loop of wire 
>> suspended within the pine tree opening says that if the bottom of the 
>> loop ( horizontal wire ) wire rests upon the ground that the BW of 
>> the loop goes way up and so do the losses...
>> Raising the bottom wire just a few feet above the ground narrows 
>> bandwidth and losses significantly... So today I will spend hoisting 
>> the bottom wire of this loop to about 10' off the ground and see what 
>> those numbers say...
>>
>> Ground conductivity here on the BC band is between poor and rotten 
>> and is mostly silica sand... So I imagine an efficient loop in 'free 
>> space', but that is not the case as yet...
>>
>> After today there is one remaining try at reducing 'ground losses' 
>> and hopefully that will not be a secret by sundown... After that, 
>> back to microwave like wire antenna modeling for seniors... 50 mhz. 
>> seems best for model building/scaling...
>>
>> Maybe skydiving is next...
>>
>> 73s de Dave, still stuck in reality...
>>
>>
>> On 9/1/2018 11:02 PM, patrick hamel wrote:
>> Impractical??
>> When I was a novice someone gave me an old (1930 vintage) Handbook 
>> including wooden lattice tower construction.
>> A 100 foot lattice tower with cross arms and side ropes to hold the 
>> loop in shape is possible.
>> If you have the room and money for the tower you might be able to 
>> afford rigid (threaded) aluminium conduit for the radiator (it does 
>> exist). Today we have various plastics which would make a lattice 
>> tower long-lasting instead of the treat-it-yourself wood (barrel of 
>> creosote) I remember being discussed. Today we have bucket trucks for 
>> tree-trimmers and construction cranes that could make erection of 
>> such a tower a safe and practical.
>> 73,
>> Pat W5THT
>>
>>
>> ------------------------------------------------------------------------
>> *From: *"J Mcvey via 600MRG" <600mrg at mailman.qth.net> 
>> <mailto:600mrg at mailman.qth.net>
>> *To: *600mrg at mailman.qth.net <mailto:600mrg at mailman.qth.net>, "Dave 
>> Riley" <dave.riley3 at verizon.net> <mailto:dave.riley3 at verizon.net>
>> *Sent: *Saturday, September 1, 2018 9:23:33 AM
>> *Subject: *Re: [600MRG] More 630m antenna efficiency...
>>
>> I played with the loop calculator at the link that you provided.
>>
>> Got some impractical results:
>> diameter 90.5 feet  ( I used a length of 300 ft which was in the 
>> range they suggested)
>> conductor 0.9 inch
>> Q= 497 !!!!
>> BW = 1.27 KHZ
>> Cap voltage = 5000 volts RMS
>>
>> Even with a conductor almost 1 inch in diameter , the Q is 497 and 
>> the BW is 1200 HZ
>> 1) 90.5 foot diameter ? how does one build and install such a structure?
>> 2) How does one tune ( and keep tuned) something with a Q of 497? 
>> Servos with continuous feedback?
>>
>> I thought the whole thing was "loopy"
>> On Saturday, September 1, 2018, 9:37:42 AM EDT, Dave Riley 
>> <dave.riley3 at verizon.net> <mailto:dave.riley3 at verizon.net> wrote:
>>
>>
>> It's fun to see the banter and playback all around... Termination of 
>> this discussion ended up around 1.65/1 SWR, ( self written results ) ...
>> Brain food, that's all it is, and maybe a good antenna...
>>
>> Now for the next batch of toil and trubble to wrestle over...
>>
>> I am a confirmed loopest and have sworn NEVER to divert ANY RF in to 
>> a lossy ground system... EVER...
>> To that end I promise to keep all power possible in the LOOP, as it 
>> were... Enuf of it gets lost in the ground as it stands already...
>>
>> The next personal challenge here is to arrive at the possible EIRP 
>> from this loop, 5W eirp for the very least RF power input...
>> Right now it is costing me about 13 watts in order to claim 5W eirp 
>> +/-...
>>
>> I started out with a monster dog wire loop 630m antenna made from 
>> e-bay for very cheap $$ and I was astounded by how simple a single 
>> wire antenna on our new band could perform...
>> I only added a good vacuum variable cap. in series and used a good 
>> mix for the Ferrite coupling transformer...
>>
>> I use this small loop transmit formula which may or may not be the 
>> best bottom line in computation...
>> http://www.66pacific.com/calculators/small-transmitting-loop-antenna-calculator.aspx
>>
>> I am now at the stage of trying to increase the wire diameter from 
>> #14 stranded copper to something larger for cheap money and lots of 
>> gain, say 1/4"...
>>
>> Here is what I have up now:
>> 450' circumference loop, using double CATV RG6a coax with a copper 
>> runner...
>> https://www.ebay.com/itm/Directv-Dual-Black-CR03BDR0-05-Ground-RG6-Coax-Cable-on-EnviroReel-ReeLogic-Reel/163202369537?hash=item25ff9e8801:g:WRgAAOSwc2FaLfFs
>>
>> It is lightweight, contains 5 separate conductors, and when 
>> paralelled together must add up to something more than .25" diameter 
>> or so...
>> Maybe today I will measure say 25' of each wire on the RF bridge and 
>> report back...
>> Below is a 'rac' table taken from Bill Ashlock's work as my starting 
>> point of reference;
>>
>> We read in the book of Bill's, the efforts derived from the following;
>> ConductorType   Rac ohms Tot Rac ohms
>> #12 awg          1.15    1.37/1.48 0.83/.80      0 db     ** 
>> Reference start point...
>> #10 awg          0.92    1.14/1.25 0.91/.87    +0.8 db
>> #8 awg           0.72     .92/1.03 1.02/.96    +1.8 db
>> #6 awg           0.57     .79/.90 1.09/1.03    +2.4 db
>> #4 awg           0.45     .68/.79 1.18/1.10    +3.1 db
>> #2 awg           0.36     .57/.68 1.29/1.18    +3.8 db
>>
>> #12 x 4          0.32    .55/.66 1.31/1.20       +4.0 db
>> #12 Litz         0.57    .79/.90 1.10/1.03       +2.4 db
>> #12 Litz x 2     0.30    .59/.70 1.27/1.16      +3.7 db
>> #12 Litz x 4     0.16    .38/.49 1.58/1.39      +5.6 db
>> RG-8/11          0.38    .60/.71 1.26/1.16      +3.6 db
>> ½” Cu pipe       0.15    .37/.48 1.60/1.41       5.7 db  **** BEST by 
>> far  LOWEST a.c. 'R' measured
>>
>> This table is based on Bill Ashlock's testing @ 185kc. and a 200' 
>> circumference square loop... 50' on a side...
>>
>> My question now is what will the RAC be of the 5 separate RG6A 
>> conductors wired together in parallel???  I guess @ .4" equivalent 
>> diameter +/- for;
>> Antenna efficiency: 34% (-4.7 dB below 100%)
>> Antenna bandwidth: 2.07 kHz
>> Tuning Capacitance: 622 pF
>>
>> Capacitor voltage: 1,573 volts RMS
>> Resonant circulating current: 2.92 A
>> Radiation resistance: 0.402 ohms
>> Loss Resistance: 0.772 ohms
>> Inductance: 181 microhenrys
>> Inductive Reactance: 539 ohms
>> Quality Factor (Q): 230
>> Distributed capacity: 369 pF
>>
>> Antenna "circumference": 450 feet
>>
>> That is with one copper wire carrier, two solid shields of 75 ohm 
>> coax. approx .240" each, and two center conductors ( copper ) #18 or 
>> so...
>>
>> It is very tempting to go to Lowe's and buy 10' sections of 3/4" 
>> schedule 'M' copper pipe!!! Am resisting...
>> It is already too easy to make 5W eirp from the low power transverter 
>> here... Why re-invent the wheel??
>>
>> Comments??
>>
>>
>>
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