Several things...
The tower and any feedlines are in play. The tower should be connected to
the radials. This would be an issue whether the vertical antenna was an L, a
T, or a folded monopole. This was worth nearly 5 db at one installation.
Feedlines and rotor cables up the tower should be at RF ground at the base.
Without the ground connection the various antennas will be connected by the
feedline shields via switches presenting strange changes if one or the other
cable is removed from the switch. Sound familiar?
Good luck. 73, Guy.
On Sat, Nov 7, 2009 at 2:37 PM, Mike & Coreen Smith <ve9aa@nbnet.nb.ca>wrote:
>
> sEE MY COMMENTS BELOW
>
> Where is your T bottom with respect to the tower,
>
> INCHES AWAY FROM BASE OF TOWER.
>
> how many and kind of radials do you have below the T,
> A COUPLE DOZEN 1/8->1/4 WL RADIALS
>
> is there a direct connection to the tower, and does the tower base have
> radials?
> BASE OF TOWER SUNK INTO HUGE BLOCK OF CONCRETE. NOT GROUNDED TO RADIAL
> SYSTEM.
>
> Guy.
>
> On Sat, Nov 7, 2009 at 11:30 AM, Mike & Coreen Smith <ve9aa@nbnet.nb.ca>wrote:
>
>> OK, on a lark, I am going to try something. I just unhooked my A-D twin
>> drooper, err, I mean sloper from the
>> switchbox, then took a chunk of wire and shorted it out @ the PL-259 end
>> at
>> the base of the tower.
>>
>> The SWR on my T-vertical changed dramatically. (for the better). There
>> must
>> have been a lot of interaction, either through the switchbox itself, or
>> just
>> proximity??
>>
>> I'll leave it unhooked for a day or two and see how I make out with no
>> reference antenna at all.
>>
>> I'll be the 30/S9 signal on the band tonight.......(hee hee)
>>
>> Thanks for all the emails. If this fails or produces mixed results, I may
>> modify the antenna swaitch back to original if I can remember what I did
>> to
>> begin with(?) or put a new remote switch in there........or do as a couple
>> suggested and mount an inverted VEE up near the top of my tower (44'),
>> however that's really a last resort....I don't want a cloud burner.
>>
>> Another option I guess , is to lay out 100 more radials. Do-able, but
>> wouldn't look forward to it ;-)
>>
>> Mike VE9AA
>>
>> Mike, Coreen & Corey Smith
>> 699 Rte 616 Keswick Ridge
>> NB
>> Canada
>> E6L 1T1
>> ----- Original Message -----
>> From: Kenneth D. Grimm, K4XL
>> To: Wes Attaway (N5WA)
>> Cc: 'Mike & Coreen Smith' ; topband@contesting.com
>> Sent: Saturday, November 07, 2009 11:49 AM
>> Subject: Re: Topband: Low Alpha Delta DX-A twin sloper BEST antenna here
>> -
>> howcan that be?
>>
>>
>> Mike,
>>
>> The procedure described by Wes below is exactly the approach I would
>> take. If you do this, I'm betting that you are left with #1 below,
>> since you said you previously had your antennas over "soggy ground."
>> Rocky and soggy are significantly different.
>> Good luck with your gremlin chasing.
>>
>> 73,
>> Ken - K4XL
>>
>> Wes Attaway (N5WA) wrote:
>> > Mike:
>> >
>> > 1. Maybe the type of rocky ground is the reason.
>> > 2. Take down all the other wires and check the L (or T) by itself,
>> still
>> > using switchbox.
>> > 3. Take out the switchbox and just feed the antenna directly (still by
>> > itself, no other wires)
>> > 4. If things are still bad then the problem probably has something to
>> do
>> > with your location.
>> >
>> >
>> > ------------------ Wes Attaway (N5WA) ------------------
>> > 1138 Waters Edge Circle - Shreveport, LA 71106
>> > 318-797-4972 (office) - 318-393-3289 (cell)
>> > Computer Consulting and Forensics
>> > -------------- EnCase Certified Examiner ---------------
>> >
>> >
>> > -----Original Message-----
>> > From: topband-bounces@contesting.com
>> [mailto:topband-bounces@contesting.com]
>> > On Behalf Of Mike & Coreen Smith
>> > Sent: Saturday, November 07, 2009 6:44 AM
>> > To: topband@contesting.com
>> > Subject: Topband: Low Alpha Delta DX-A twin sloper BEST antenna here -
>> > howcan that be?
>> >
>> > Sorry for the long and rambling post. . . .
>> >
>> > OK gang, I know antennas "fairly" well, but this has me
>> stumped...really
>> > REALLY stumped. I've beat myself up over this for 2 yrs. straight. I
>> just
>> > can't get it. I am (almost) ready to rip everything down and start
>> from
>> > scratch)
>> >
>> > I posed a ~similar~ question last year and have tried some different
>> things,
>> >
>> > but I'm losing my patience with the wire here (hi)
>> >
>> > BACKGROUND:
>> > At my old QTH, I ran an inverted L...5/16thWL and fed with a 800pF cap
>> in
>> > series. A dozen to two dozen 1/4wl radials(depending on how many got
>> broken
>> >
>> > in the summer)over soggy ground. It meandered up 50-ish or so feet
>> with
>> the
>> >
>> > remaining 117' up/down/over/under trees --even the tip sloped back
>> towards
>> > the ground 20' or more.....and it ROCKED....I mean, I wasn't any VE1ZZ
>> or
>> > anything but I felt I was upper middle crust of the W1/VE1 pileup. I
>> also
>> > had the exact same tower and exact same Alpha Delta DX-A twin sloper up
>> (for
>> >
>> > reference) and it s*cked...really bad. Easily several S units below
>> > anything else on 40-80-160m
>> >
>> > NOWADAYS:
>> > Fast forward to new QTH...same 48' DElhi self supporting tower set in
>> > concrete....same 2 long 6m yagis on tower (48/64')....same lil' sloper
>> > mounted @ 24' off side of tower....
>> > I have tried 2 iterations of a plain inverted L.....currently it's a
>> "T"
>> > antenna. Sloping 55' or so up and 2 T's @ 55' or so each sloping @
>> aprox
>> 45º
>> >
>> > to the ground....loads nicely with a few uH @ the base. Seems quieter
>> than
>> > the A-D twin.
>> > I have tried shunt -and- series feeding my 48' tower (no problem to
>> do).
>> > They have all loaded well and I got a good SWR match with a usually
>> narrow
>> > window 50Kcs maybe of 2.1:1 SWR of which to operate in. I have 25 or
>> so
>> > 1/8wl to 1/4wl radials - 1" below the grass. Ground is rocky shale?
>> sort of
>> >
>> > stuff. My QTH is on a nice high ridge and I do quite well on VHF and
>> other
>> > HF bands.
>> >
>> > My signal is pitiful on **all** the 160m antennas I've tried....with
>> the
>> > exception of the 1/4WL Dx-A twin sloper @ 24' !!! (it's best but it
>> barely
>> > works)
>> >
>> > The little/low twin sloper off the side of the towe is ALWAYS the
>> loudest on
>> >
>> > the band....by usually 6dB or more........I know this can't be right.
>> >
>> > How can this be? I am using a 4-1 antenna switchbox (Ameritron I
>> think)
>> @
>> > the base of the tower which the antennas all share. Many years back I
>> > modified it so all antennas "floated" (instead of being grounded) when
>> not
>> > selected as I was using this as a K8UR sloper system switchbox at one
>> time.
>> > I am pretty sure (but not 100%) that I even ran a separate chunk of
>> coax
>> > right out to an inverted L last fall in desperation. I do lots of
>> antenna
>> > experimenting, so it's sometimes hard to remember the 45th iteration of
>> a
>> > trial I had a couple years ago, hi.
>> >
>> > I *DO* notice significant SWR curve changes on the lil' wee sloper if I
>> make
>> >
>> > any mods to any of the other "REAL" 160m antennas.
>> >
>> > I either have interactions in the switchbox, or proximity between
>> antennas
>> > or something that I am totally missing. All 160m antennas are quite
>> close
>> > (less than 20-30' away).
>> >
>> > Logic tells me there is no way in heck the very low Alpha-Delta DX-A
>> twin
>> > sloper can __always__ be the best antenna to transmit and receive on.
>> YET
>> > is is !!? From what I see on the cluster, web and hear on the air, I
>> can
>> > hear quite well, but DX stations normally have to be 559-579 before I
>> even
>> > get a QRZ.....I am currently running ~750W.........
>> >
>> > I'm cracking up.....too much listening to QRN.......sorry for the long
>> post.
>> >
>> > Thanks for any insight. I am ready to put a Webster Bandspanner on my
>> > mobile and go sit out in the yard and DX.
>> > <hi>
>> >
>> > VE9AA Mike
>> >
>> > Mike, Coreen & Corey Smith
>> > 699 Rte 616 Keswick Ridge
>> > NB
>> > Canada
>> > E6L 1T1
>> > _______________________________________________
>> > 160 meters is a serious band, it should be treated with respect. - TF4M
>> >
>> > _______________________________________________
>> > 160 meters is a serious band, it should be treated with respect. - TF4M
>> >
>> ------------------------------------------------------------------------
>> >
>> >
>> > No virus found in this incoming message.
>> > Checked by AVG - www.avg.com
>> > Version: 9.0.698 / Virus Database: 270.14.53/2486 - Release Date:
>> 11/07/09 02:38:00
>> >
>> >
>>
>>
>> --
>> Ken K4XL
>> k4xl@arrl.net
>>
>> *** BoatAnchor Manual Archive ***
>> On the web at http://bama.sbc.edu and http://bama.edebris.com
>> FTP site info: bama.sbc.edu login: anonymous p/w: youremailadr
>>
>> _______________________________________________
>> 160 meters is a serious band, it should be treated with respect. - TF4M
>>
>>
>>
>> ------------------------------------------------------------------------------
>>
>>
>>
>> No virus found in this incoming message.
>> Checked by AVG - www.avg.com
>> Version: 8.5.425 / Virus Database: 270.14.52/2485 - Release Date:
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>> 19:39:00
>> _______________________________________________
>> 160 meters is a serious band, it should be treated with respect. - TF4M
>>
>
> ------------------------------
>
>
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> Checked by AVG - www.avg.com
> Version: 8.5.425 / Virus Database: 270.14.52/2485 - Release Date: 11/06/09
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>
_______________________________________________
160 meters is a serious band, it should be treated with respect. - TF4M
|