1000 foot longwire antenna's
pli...@telkomsa.net
antenna rather than upgrade to a better radio. This is a bit like
which came
first? the chicken or the egg? I have had extensive experience of
using
1000ft longwires or beverage antenna's on my DXpeditions over the
years and
indeed they do pull in the signals something awesome. But they also
pull in
more interfering stations that want to blot out your faint DX target,
and
also whatever QRM/RFI noise is floating around, they pull more of that
in
too.
So at the end of the day it still means it is better to DX with a top
end
radio that suppresses and minimises the offending signals and QRM that
are
interfering with your faint DX target.
Over the years I gradually upgraded my radio's to what I thought was
the
ultimate, a Drake R8B. I was quite satisfied with that until I was
loaned a
Rohde & Schwarz. Although the R & S did not have any more bells and
whistles
than my Drake, it was so clearly superior to my R8B that from then on
I
hankered after a better radio. The R&S just pulled in faint stations
that
did not even register on the R8B and then was also better able to
resolve to
audibility stations that were interfered with much better than the
R8B.
So I watched developments and then my good friend Guy pointed me
towards the
Icom IC-756PROIII, which I later acquired. This radio was indeed
better than
my R8B, see:
http://www.dxing.info/equipment/icom_ic756_plimmer.dx
So the 756Pro3 has really proved itself in the field, culminating in
the
catch of a lifetime: 1410 Khz, CFUN, Vancouver BC, Canada, some 14,000
miles
away from the Seefontein DX site. Whether or not I would have got this
catch
on my old R8B is a moot point - I don't think so as it was extremely
faint
and on the border of audibility, and my DX mates didn't get it either.
So I
am happy that the 756Pro3 paid for itself and that is why I am now
upgrading
to the new Icom IC-7700 which should be here in April. If I get only
one
more rare catch I will be satisfied that the 7700 has been a
worthwhile
investment.
But to keep things in perspective, I think the things that are
important to
good DX reception are, in order of importance:
1st.] A decent antenna, the best you can afford or rig up.
2nd.] Location. Most of us live in the city or suburbs and are either
in
condo's or on limited size plots, so our options are limited. That is
why
serious DXer's go to a lot of trouble and expense to find the "ideal"
DX
location. When you find a decent place, the results are VERY
rewarding.
3rd.] The radio. again, get the best you can afford. The results just
get
better and better.
I would liken our hobby to any sport. If you take golf and Tiger Woods
for
example. He has only the latest and most expensive cutting edge
equipment.
If he gets the latest $3000 putter and it allows him that extra inch
nearer
the hole, he is satisfied. So it is with radio gear and antenna's.
Have fun and good DX
John Plimmer, Montagu, Western Cape Province, South Africa
South 33 d 47 m 32 s, East 20 d 07 m 32 s
RX Icom IC-756 PRO III with MW mods
Drake SW8 & ERGO software
Sony 7600D, GE SRIII, Redsun RP2100
BW XCR 30, Sangean 803A.
Antenna's RF Systems DX 1 Pro Mk II, Datong AD-270
Kiwa MW Loop, PAORDT Roelof mini-whip
http://www.dxing.info/about/dxers/plimmer.dx
dxAce
pli...@telkomsa.net
> That would be longpath then, pretty good.
>
Oops! Sorry = error!!!
That should read 10,000 miles/16,000 km's, so it is shortpath on a
darkness run. The path lies over the Atlantic and enters Canada near
St. John's and passes near Quebec then over the Prairies, past
Calgary, over the Rockies to Vancouver.
John Plimmer, Montagu, South Africa
mi...@sushi.com
It's been my experience with the Wellbrook ALA100 that more is more. I
have found increasing the length of a long wire to have diminishing
returns.
This would be a question for Andy Ikin at Wellbrook, but I believe the
ALA100 is gaining aperture based on the area of the loop. Making a
long wire longer should be a linear improvement, not a square power.
In the case of the ALA100, you would be increasing the length up to
the point where the loop is not longer considered small. For a long
wire, is their any improvement after reaching half a wavelength?
I find it hard to believe I could improve over my AR7030 reception,
outside of some fancy external synch scheme.
Regarding R&S, generally "pro" receivers assume you have a preamp by
the antenna. I find it hard to believe out of the box it is more
sensitive than commercial gear that doesn't presume a preamp will be
used.
dxAce
mi...@sushi.com
It would help if you asked the question in a more intelligent manner.
For instance, kidding about what in particular?
If it is the use of preamps with high end gear, this is obvious. Just
look at the high end icom gear. It is no where near as sensitive as a
say a HT. But you design a HT to have a small antenna, while your
R8600 will have larger iron attached. Also historically, preamps have
become quieter as technology improves. So with pro gear, you upgrade
the preamp and still keep the radio. The AR7030 is designed so that
you can turn the internal preamp off. This is not for dynamic range
consideration since the radio already has a wide dynamic range.
Rather, it is to allow for low noise preamps, multicouplers, etc.
You are welcome. Glad to be of service.
dxAce
Telamon
<ffe2e672-9551-47dd...@y77g2000hsy.googlegroups.com>,
pli...@telkomsa.net wrote:
You bring up a good argument but tangled in it are a number of factors
that all affect reception.
The chicken and egg question is easy. The antenna is the egg and it
comes first. All antennas are not created equal and are designed to
achieve certian objectives in reception just like radios. In the extreme
the antenna can be highly directional where the desired signal can be
specifically enlarged relative to other signals and noise. In the radio
it is mainly blocking and bandpass filtering. Both antenna
directionality and gain or radio gain, blocking, and selectivity can get
you where you want to go to get that DX.
I'm familiar with Rohde & Schwarz signal generators but not their
receivers. You don't mention the model number of the receiver but I can
speculate on a few things. One would be cost. Chances are the R&S
receiver costs 10 to 30 times the Drake. Two would be that the R&S would
not have such niceties as sync detection or tone controls.
I don't think going to ham transceivers is the way to go unless you are
a ham or are working toward being one. I'm not interested in being a ham
and I don't want to buy a transceiver.
DSP can be a good thing but it depends on how it is engineered. I have
both kinds of radios and the DSP type appears to have no advantage in AM
mode. The DSP radio does appear to work better for SSB. I would expect
that for digital modes the DSP would clearly be superior. Here the
crucial parameter at play I believe is bandwidth. Designed properly DSP
IF and AF filtering is generally much better than analog and so in
application where this is more important the DSP radios can perform
better. Anyone who has operated a radio with several filters has most
likely noticed that as you decrease the bandwidth the receiver noise
floor drops improving signal to noise. Since DSP filters can have very
steep walls and depth over analog filtering you would expect improved
signal to noise and better reception where narrow bandwidths are in play.
There are always performance tradeoffs and you only address what a DX'er
might want and certainly not what I would want in a receiver. What I
want is good performance and good sound. Many DSP implementations have
lousy sound quality with a lot of distortion. Here I noticed that with
DSP you can have a signal in the clear without the pops and hiss and yet
not be able to understand what is being said. I have listened to tapes
of DSP radio reception and noticed that besides not being able to
understand many of the words in speech that it was very difficult to
listen to the recordings after a while. Even when I had a transcript of
what was said and replayed the DSP recordings over again I still could
not make out some of the words. I also found it very tiring to listen to
DSP sound. I'll take the pops, whistles, and hiss over the DSP
distortion anytime.
Here is an observation I have made on DSP sound. Have you ever listed to
a coast to coast show with one of those reverse speech guys on? I don't
know about other people but sometimes listening to DSP SW recordings was
not unlike listening to those reverse speech recordings.
--
Telamon
Ventura, California
Telamon
<0e139be2-0d76-4ecd...@e60g2000hsh.googlegroups.com>,
mi...@sushi.com wrote:
Yes, other signals and noise come from all directions. The antenna would
have to be more directional along with increased gain to be more
effective.
> This would be a question for Andy Ikin at Wellbrook, but I believe the
> ALA100 is gaining aperture based on the area of the loop.
Yes.
> Making a long wire longer should be a linear improvement, not a
> square power. In the case of the ALA100, you would be increasing the
> length up to the point where the loop is not longer considered small.
> For a long wire, is their any improvement after reaching half a
> wavelength?
A feed line connected to the end of a half-wave antenna would receive
very little at the half-wave frequency. Optimum would be 1/4 wave.
> I find it hard to believe I could improve over my AR7030 reception,
> outside of some fancy external synch scheme.
That's a very good radio.
> Regarding R&S, generally "pro" receivers assume you have a preamp by
> the antenna. I find it hard to believe out of the box it is more
> sensitive than commercial gear that doesn't presume a preamp will be
> used.
R&S make test equipment and not SW receivers as far as I know. Chances
are John used a receiver that is designed to test received signals and
is very expensive.
--
Telamon
Ventura, California
Telamon
<62539dc1-536d-49dd...@h11g2000prf.googlegroups.com>,
mi...@sushi.com wrote:
< SNIP >
Specifically, a long wire high in the air would not be very directional
where a long wire near the ground would have beverage characteristics.
The beverage would have better signal to noise if pointed at the desired
signal where the very high wire would not.
--
Telamon
Ventura, California
pli...@telkomsa.net
because the subject of antenna's is vast and the number of huge
technical tomes written on the subject will keep you going for the
rest of your life.
I see you have a poor opinion of DSP receivers, so I can only presume
you experienced the faults of the early models that only had 16 bit
engines. My 756Pro3 has a 24 bit engine with 32 bit processor and I
assure you suffers from none of the problems you mention that applied
to the earlier offerings like the JRC NRD545D.
I wrote a detailed description of my experiences of the 756Pro3's
audio and filter at:
http://www.dxing.info/community/viewtopic.php?t=2404&sid=e7711d6607b7f67e8ff1aab600e79c4f
I assure you the audio on the 756Pro3 is top notch, only thing it
lacks is a synch detector.
Rohde & Schwarz did indeed make receivers for HF, the last of them
being the EK895, which unfortunately was so expensive that it could
only be affordable to professional and government operations. They
don't make stand alone receivers anymore, only modular HF units that
fit into a more comprehensive monitoring PC run station. The R&S EK
receiver I had use of for several months was the analogue model just
before the EK895 - it's performance was just awesome. It's outstanding
performance was not due to any fancy pre-amps, but rather superb
circuitry, high quality components and build, and top notch filters.
In performance the only hobby radio that ever came near it in
performance was my pals Drake R7A. Both these receivers could resolve
DX signals that my R8B couldn't.
Of course it's different tricks for different dicks. What I am looking
for in a top end receiver is a complete overkill for the fella that
just want's to potter around and get good sound out of AM HF
broadcasts.
OHIM (Oh hell it's Monday) enjoy your radio and good listening
John Plimmer, Montagu, Western Cape Province, South Africa
South 33 d 47 m 32 s, East 20 d 07 m 32 s
RX Icom IC-756 PRO III with MW mods
Drake SW8 & ERGO software
Sony 7600D, GE SRIII, Redsun RP2100
BW XCR 30, Sangean 803A.
Antenna's RF Systems DX 1 Pro Mk II, Datong AD-270
Kiwa MW Loop, PAORDT Roelof mini-whip
http://www.dxing.info/about/dxers/plimmer.dx
On Mar 3, 4:35 am, Telamon <telamon_spamshi...@pacbell.net.is.invalid>
wrote:
> In article
> <ffe2e672-9551-47dd-94f0-159cd44e9...@y77g2000hsy.googlegroups.com>,
>
>
>
>
>
> plim...@telkomsa.net wrote:
> > dxAce raised the point that he would prefer to upgrade to a 1000 foot
> > antenna rather than upgrade to a better radio. This is a bit like
> > which came first? the chicken or the egg? I have had extensive
> > experience of using 1000ft longwires or beverage antenna's on my
> > DXpeditions over the years and indeed they do pull in the signals
> > something awesome. But they also pull in more interfering stations
> > that want to blot out your faint DX target, and also whatever QRM/RFI
> > noise is floating around, they pull more of that in too.
>
> > So at the end of the day it still means it is better to DX with a top
> > end radio that suppresses and minimises the offending signals and QRM
> > that are interfering with your faint DX target.
>
> > Over the years I gradually upgraded my radio's to what I thought was
> > the ultimate, a Drake R8B. I was quite satisfied with that until I
> > was loaned a Rohde & Schwarz. Although the R & S did not have any
> > more bells and whistles than my Drake, it was so clearly superior to
> > my R8B that from then on I hankered after a better radio. The R&S
> > just pulled in faint stations that did not even register on the R8B
> > and then was also better able to resolve to audibility stations that
> > were interfered with much better than the R8B.
>
> > So I watched developments and then my good friend Guy pointed me
> > towards the Icom IC-756PROIII, which I later acquired. This radio was
> > indeed better than my R8B, see:
> >http://www.dxing.info/equipment/icom_ic756_plimmer.dxSo the 756Pro3
> Ventura, California- Hide quoted text -
>
> - Show quoted text -
m II
>> For instance, kidding about what in particular?
>
> Your last sentence. Hope you listen better than you can read :-)
==================================================================
*********************************************
=============================================
ASU
nagihciM
ecAxd
.WS fo dlrow eht ni ehcin ruoy dnif lla uoy taht epoh ylerecnis I ,eybdooG
.SRR pu evig ot dediced ylpmis ev'I ,eroferehT
..etot ohw esoht dna ,setnatubed eht ,xuaf eht etacude
ot gniyrt SRR no ereh emit elbaulav ylgnisaercni ym fo hcum ot raf pu gnivig
ma I taht dnif I tub ,sdneirf evawtrohs ynam ym ,siht yas ot tnaw t'nod yllaer I
=============================================
*********************************************
!spmats tcelloc I
.ercassaM reviR dnilB
eht ot drawrof gnikool ,ngiapmac gnirpS eht rof nalp I ,elihwnaeM
...yob ,tuhs htuom ykcunaC nikoof ym peek d'I ...t'nod uoy fI
?ecnahc a tog uoy knihT ?niw thgim uoy knihT
?daeh tihs ,raw ot og annaW
...skcus huDanaC
...erac fo etats dlroW drihT ykcunaC eht staeb ti teb d'I ,etar yna tA
.gnorw sgniht fo tol a dnif thgim eno dnuora
ekop shaggin ykcunaC uoy fi tub ,doog etiuq era seitilicaf AV yllautcA
.sdratsab sselpah eht pleh tiripS taerG eht yaM
..natsikcunaC htiw RAW ta won m'I ,deednI
.drater' nikooF
..hcteeb elteel drater nikoof ...noos pu ekaw uoy tseB
!eineewdE ekiL !sdratsub nikooF
.u naw now sykcunaC
leer eht nebew dab os eb u ...yob dab calpmus ot u nes eb enog eW
..stssisar zamud era zyob ykcunaC meD
.....daehtihs ,niaga yrT
?he ,niwonk
eb uy ,ekahs ad ay nivig eb ot nisiurc eb I ,dexif eb edir ym teg I
..zuC ,ffo reknaw rehtona dessip ew sseug I ,nmad hO
..yawa knirhs lliw ti ,wardhtiw uoy sa tub ,drah eb yam ti wonk I
..kcunaC niggirf bmud rehtona tey ta OAFML
...rekcus kcoc ,erofeb siht enod ev'uoY
...seuqehc ytlayor ym ta kool dna tis I sa OAFML
...rekcus kcoc ,noitnetta yaP
!pu ti peek uoy fi ssA yoB etihW cinapsiH
ekaf yrros ruoy tisiv emoc annog era dooG fo secrof eht ,eineewdE .rM
)3( !erif no senulatnap ,rail ,raiL
!toggaf yssup elttil diputS
!ytidiputs si huDanaC
?em nidnats'
eb ay ,su neewo eb sykcunaC ssa mud med tad ,dron pu noitatnalp R now I
..dratsaB kcunaC adnik gnikcuS
kcoC ,eroG lA ,tnirptooF nobraC ,larebiL ecin a gnieb uoy ,won no emoC
!sesu ecAxd tahw t'nsi ffuts taht tuB
ti pu nolemretaw a ffutS
..yob rekcus kcoc ,ereh snoitacidem oN
.llew sa doG ot esneffo
na ylekil naht erom dna ,em ot esneffo na si gniyl lacigolohtap ruoY
!uoy ekil rekcus kcoc elttil ekaf saw eh ,haN
...eineewdE ,uoy ekil tsicar a ton m'I ,yrroS
tnar larebiL rehtona tey dnA
:yob ,ereh ylper kciL-yaG ruoy tresnI
.si eh erus I
!snacireM laer R syyyob veetan su taht nnnatsrennu enod yeD
?drater ,ti teG
.kcap egduf ,niaga emit dna emit nevorP
!drater ,em rof dekrow uoy taht hsiw uoy ekil tsuJ
.drater deldda gurd uoy ,daor eht tih nehT
...niaga uoy htiw eb ot maerd a ekil s'ti ,ti eveileB
...kcid ym kcus ,thgir aY
?yob ,taht htiw melborp a tog ay .snaidnI imaiM htob era ew ,lla ta toN
.nielK hpesoJ deman wollef a ralucitrap ni
,ynapmoC tnemtsevnI notgnitnuH eht htiw ssenisub od t'noD
.yad rehto eht XAESF fo serahs 0001 thguob I ,kceH
.ffuts taht eltnamsid ot evah ll'ew
s'ssa yrros ruoy evas ot niaga ecno dnop eht revo emoc ew emit txeN
?od I dluohs reve tahw ,flesym yrtsecna ecar dexim fo m'I ...nmaD
.ti rof knaht ot syoB recnarP ehT
dna evaD rekcuskcoC evah ll'uoy ,DH tnorfnoc od uoy nehw dnA
.tnemercxe fo eceip cinapsiH ekaf uoy ,ti revo teG
.tsdim ruo ni drater deldda gurd a evah ew ,uoy ni ,lleW
.drater nik00f uoy ,SRR fo ffo lleh eht teg dna hsur eht taeb ,oS
.deldda gurd ylsuoivbo
si ti/ehs/eh nehw regnessem eht kcatta ylno I ,haN
.sdrater deldda gurd eht wercS
.dnalevelC attuo 'nikcap ssa nik00f ruoy tnes ehs nehw uoy evag rehtom
ruoy tahw si taht taht si evaw trohs tuoba wonk uoy gniht ylno ehT
.recnarp nik00f uoy ,kcab elihw a uoy ot detacidni I tahw hcum ytterP
!ssa kcil-yag 'nikcik evol I ,yeH
.loof deldda gurd ,daor eht tiH
!taht swonk enoyrevE .kcab gnirpS dna drawrof llaF s'ti ...no emoc hO
!ssabmud ,ti rof oG
.kcap egduf ,uoy sa llew sa toN
ecAxd yb SB eht edils reven nac enO
!em rof hguone doog s'taht
!sesu ecAxd tahw s'tI
?syob eht dna uoy rof tnacirbul dooG
!uoy naht rehtraf tnew I tsael tA
.emit retfa emit ,evah ylniatrec I ,hO
?wollaws ro tips uoy oD
....'yob revodneb' eht era uoy yltnerappA
)2( !erif no senulatnap ,rail ,raiL
!eno xuaf ho ,somoh 'raef' t'nod I
.gnol yad lla ssa nik00f ruoy pu daeh ruoy peel uoy ,ylsuoivbO
.ettevroC
reh em evael lliw yellaV lliM ni nisuoc ssabmud ym ,yllufepoh ,dnA
...yawa seidoog
s'esle sydobemos evig ot ydaer syawla era sepiwssa larebiL 'nikcuf uoY
.ssa nik00f ruoy pu si daeh ruoy ,syawla sA
!sdrat' eb ot deredisnoc era uoy yhw lla retfa si tahT
.sretemarap fo tes eno nopu detaxif ytterp era sdrat' uoy ,si gnihT
.drat' eht ta OAML
!recnarp elttil uoy ,etacsufbO
!kciL-yaG .rM ,OAFML m'I
!tnadep ,ssa ym ssiK
!yob ,naikcunaC ton s'tahT
.omma knihC esu t'nod I
..omma fo esac rehto taht tup I did erehw woN
.ffuts esenihC eht ekil t'nod I .omma naissuR saw tI
.tol a t'nsi sdnuor 000,01 dnA
.pu derrits steg aneewde
sa hcus syob drat meht esac ti stog llits I ...omma thguob dna tnew I
ffuts knihC esu t'nod I
!evael ot deksa ton saw I ,kcunaC kcufbmud ,yeH
!yob dratsab dlo gniyl yllacigolohtap
,gnikcus kcoc tneluduarf uoy ,tnaw uoy lla KCIDerp nac uoY
raey tsal 000,05$ revo em tnes .tvoG SU eht woh ynnuF
"kcunaC sselhtrow yllatot a naht erom si stnec 2 nevE"
?elpoeP nailartsuA dedrateR yzarC
!detnaw amam ruoy tahw s'tahT !yella eht nwod elffuhs uoy tseB
...kcoc kcus ohw skcunaC yoB etihW etah I esuaceB
,rehto hcae htiw
ttub pmub dna "rehto tnacifingis" ruoy htiw rehtegot teg uoy tseggus I
...dnalevelC attuo yob etihw diputs rehtona tsuj eb uoy ...huH
.yadot niaga ti ta kcab si kcunaC ssabmud ynihw roop eht ...wwwwwA
.revir nik00f a em yrC
!rail gnikcuf a er'uoy esuaceb s'tahT
.gnihsulf rof elbatius ,sepiwssa erem era yehT
!repmac yppah a m'I ,skcunaC uoy swercs ti sa gnol sA
mih ot dednah ti dah tsuj rekcuskcoc elttil rooP
!kcoC OBI emos flesruoy teg og ,tey retteb rO
?he ,tuoba kniht ot niarb gnikcus kcoc cinapsiH xuaf ruoy rof gnihtemoS
!yob ,huDanaC nik00f ni er'uoy ,yresim tuoba klaT
!boj wolb a dneirfyob ruoy evig oG
ASU
nagihciM
ecAxd
2679-533 616
:ta TMG 0330 litnu uoy pleh ot ereh m'I ,em llac ot ekil d'uoy fI
.amam rey rof etsat a emoh gnirb dna ,yob drat' ,kcoCOBI emos teg oG
!yob hctib elttil ,denruter I fi yppah yrev eb ton d'uoY
!oot nemow dna ,nemyrtnuoc ssabmud
ruoy fo tser eht dna uoY !naidanaC ssabmud uoy ,ssa ruoy tuo ti wolB
smaerd evah stoggaf uoy wonk I
!yob drater ,ti evorp t'nac uoy tuB
!yob ,ysub teG
!kcunaC ,toggaf ,ssabmud emos naht erom htrow si ,ozoB neve ,ydobynA
?yob ykcunnaC toggaf elttil uoy ,taht gninigami tsuj uoy naK
!huDanaC hsurc ew nehw edam eb lliw yrotsih weN
)1( !erif no senulatnap ,rail ,raiL
drat' lauxesomoh
elttil yrros a naht erom gnihton era dnah rehto eht no ,uoY
.SRR llac ew ecal eht tibahni ohw
syob xuaf ,tnetnoclam ,etnatubed rehto eht ekil hcum ,yob drat' gniyL
!rail lacigolohtap eht ta OAFML
!yad gnissap hcae htiw erom dna erom nrael I ,seY
toggaf nik00f eht ta OAFML
!ti evorp yob toggaf eht teL
?KO ,enola stsiybboh oidar laer eht evael dna ,kcoC OBI emos wolb oG
.ybboh XD/LWS eht tuoba elttil swonk ylsuoivbo
ohw yob drat' deldda gurd a lla retfa era uoY
!toggaf nik00f eht detsub ev'I ecnis ,OAFML m'I
!odraT' ,ssa gnicnarp ruoy pu ti ffutS
!pu yob elttil eht tuhs taht sseuG
)!YOB eht no sisahpme yvaeH( ...YOB cinapsiH xuaf elttil ,ti t'nia ,eurT
ogima ,em htiw hcuot ni teg *rethguad* ruoy evah ,'odarudE' ,yeH
!YOB ,tcartnoc a pu ward *rethguad* ruoy evaH
!skeew owt txen eht nihtiw daehrettel
smrif reh no rettel a em dnes ot *rethguad* hctib ruoy teg neht ,taerG
.yob ,daehrettel smrif reh no rettel a em dnes hctib eht evaH
.retttel a mih ekaf ot nuwemos dnif og ot tog s'eH !luhseps tsuj taht t'niA
.pu ekam thgim UOY daehrettel revetahw no rettel a em dnes hctib eht evaH
?yob he ,pu uoy tuhs yllaniF
?he ,knurd eb htob
tsum *rethguad* ruoy dna uoy neht ,yob ,rettel taht teg t'nod I fI
,,,yknaks eht dehcuot reveN
.yob ,yllanigiro ti delleps
I kniht I ekil tsuj ,ereh tuo "tnuc" ti lleps ew ,yob yssup elttil ,yeH
...ybab em llet ,haey hO
!elohssa ,*rethguad* ruoy morf rettel taht rof gnitiaw eb ll'I
...ot ffo nur setnatubed elttil uoy si ti reverehw ot gnola nur woN
?sllab tog ay kniht yllaer klof uoY
!rettel nik00f a em dnes hctib eht evaH
!nekatsim yldas eb
d'uoy kcunaC ssabmud neknurd a ot netsil ll'yeht taht tnemom a rof kniht uoy fI
?nitihtun yog av ,yuv en on tog ay ,ecraf ria on tog ay ,neppah annog t'niA
...yobyhtib yucunaC ssamud mus uoY ?hE
?sruoy em wohs nac ehs dna ,enim reh wohs nac I
rettel a em dnes hctib eht evah ,yeH
.nemyrtnuoc gnikcuskcoc rehto ruoy llet og ,lleW
!rettel eht em dnes hctib eht evaH
)5( ?tol a **HGIS** ot mees
syawla sreeuq uoy taht ti si yhw tsuj wonk ot tnaw sdnim gniriuqnI
rettel a em dnes ot *rethguad* hctib ruoy teg
!toggaf ,rettel taht em dnes ot hctib eht llet ot erus eB
.yad yreve elpoep fo sdnasuoht gnillik rof huDanaC no emahS
.loof deldda gurd ,daor eht tiH
)4( ?tol a **HGIS** ot mees syawla sreeuq uoy taht ti si yhw tsuj ,oS
!selohssa era skcunaC uoy ,pu mus em teL
"llod pu-wolb citsalp ytud yvaeh artxe eht teg ot dah I esebo os m'I"
!esiw ma I dna ,yttiw ma I ,seY
)3( ?tol a **HGIS** ot mees syawla sreeuq uoy taht ti si yhw tsuj ,oS
.yob ,rettel a em dnes tnuc eht evah ot uoy deksa tsuj I
.tnaercsim elttil uoy ,ihsus emos no kcus og woN
)2( ?tol a **HGIS** ot mees syawla sreeuq uoy taht ti si yhw tsuj ,oS
!skcunaC eht yllaicepse ,lla me' ssoT
.drat' ,daor eht tiH
.fles ruoy sa hcus srekcuskcoC
!...klof elbatcepser 'niraew xeloR t'nia erus ,skcunaC ssabmuD
!ay erad I ,syob reeuq tohs a ti eviG
!yob ,noitatnemucod taht no gnikrow ssa omoh ruoy teg woN
!era uoy tnuc bmud nmad a tahw ...LOLOLOLOLOLOL
)1( ?tol a **HGIS** ot mees syawla sreeuq uoy taht ti si yhW
!skcunaC lli yllatnem
eht pu elir dna ,gni'XD emos od ,yenom eht tsevni
,skcehc eht hsac naht evitcudorp erom gnihtyna od ot deen oN
?...diarfa ,dimit si haggiN ykcunaC eht taht eb ti dluoc ....yhw rednoW
?raw eritne eht tuohguorht tihs deye tnals
eht yb detceffa erew sevil naciremA ynam woH
...'eebannaW' tsuj er'uoy kniht I ...'eekorehC' eb ot mialc uoY
....smra s'yraM otni kcab rewolb naeb
,gnikcus kcoc eht wolb dna ,nopaew eht nopu sdnah ruoy ecalp
,tesolc eht ni hcaer tsum uoy ,dneirf citoirtap ym neht si tI
?sevlemeht gnissag fo elbapac eb yeht t'ndluow s'ocat eht gnitae retfA
.od I tahw rettam on XD ruoy naht retteb si XD ym fo llA
!gnihton rof 'ecA' em llac t'nod yehT
!ko gniod si ecA
.uoy ekil etihw ton m'I taht tcaf eht rof yad yreve tiripS taerG eht knaht I
...rehtegot tihs evitcelloc ruoy teg ot deen uoy taht dnatsrednu
ot deen )yaw siht lla ay ezirogetac I ,yrros( sreggin dnas bmud uoY
?sniarb rof tihs ,saw ti yas I diD
!nomaR ,ti ni ocat a ffutS
.beewd ykcunaC elttil gnola nuR
...yas ot gniht nmad a evah t'ndid haggiN ykcunaC eht ,nmaD
.tihs nacixeM fo eceip gniknits a si
xoF etneciV ...niaga ti yas I dna ,erofeb ti dias I
.eno on ekilsid I ,uoy ekilnu tub ,etihw t'nia I
=================================================
:)ylraluger detadpU(
saitiliM nagihciM detinU rednammoC emerpuS
,ecAxd aka ,eraL evetS fo modsiW dna tiW ehT
mi...@sushi.com
> > dxAce raised the point that he would prefer to upgrade to a 1000 foot
> > antenna rather than upgrade to a better radio. This is a bit like
> > which came first? the chicken or the egg? I have had extensive
> > experience of using 1000ft longwires or beverage antenna's on my
> > DXpeditions over the years and indeed they do pull in the signals
> > something awesome. But they also pull in more interfering stations
> > that want to blot out your faint DX target, and also whatever QRM/RFI
> > noise is floating around, they pull more of that in too.
>
> > So at the end of the day it still means it is better to DX with a top
> > end radio that suppresses and minimises the offending signals and QRM
> > that are interfering with your faint DX target.
>
> > Over the years I gradually upgraded my radio's to what I thought was
> > the ultimate, a Drake R8B. I was quite satisfied with that until I
> > was loaned a Rohde & Schwarz. Although the R & S did not have any
> > more bells and whistles than my Drake, it was so clearly superior to
> > my R8B that from then on I hankered after a better radio. The R&S
> > just pulled in faint stations that did not even register on the R8B
> > and then was also better able to resolve to audibility stations that
> > were interfered with much better than the R8B.
>
> > So I watched developments and then my good friend Guy pointed me
> > towards the Icom IC-756PROIII, which I later acquired. This radio was
> > indeed better than my R8B, see:
Noise is measured in volts per root Hz. To get the noise over a
bandwidth, you multiply by the square root of the bandwidth. So using
a 10% narrower filter reduces the noise by 4.8%. So narrowing the
bandwidth helps, but it is not a cure.
The ALA100 has the advantage of receiving the magnetic portion of the
wave, so there is less electrical noise. On MW, you get a figure 8
pattern, and subjectively a rather fat figure 8. The null is plenty
sharp, but very narrow.
In antenna analysis, you need to be aware of both gain and aperture.
Think of the photographic analogy. Antenna gain is like the focal
length of the lens. Aperture is well "doh!" the aperture. The RF field
is generally volts per meter. So obviously, more is more if the
antenna is receiving more signal and not more noise. To be really
accurate here, the noise figure of the amp is also part of the
equation. But once you have enough wire in tne air that the noise of
the amp is swamped by the signal from the antenna, I'm not sure there
is much to gain.
The notion of aperture is more easily seen in VHF on up. That is, two
meters seems to go further than 440. Well, if the antenna is the same
design, the 440Mhz antenna has less aperture than the 2 meter antenna,
even though the gain is the same. For 440Mhz to compete with 2 meters,
you would need to go to a colinear with 3 elements.
My guess would be going with multiple loop antennas would be superior
to longer longwires. Now here is where you would have to check my
math, but the two loops in parallel (summed after the ALA100 amp of
course) would have 3db less noise. The signal would be stronger as
well, but I think that would be counting the improvement twice. The
stronger signal would only be significant if the noise floor of the
radio was an issue.
Telamon
<83658b8f-83e1-4721...@q33g2000hsh.googlegroups.com>,
mi...@sushi.com wrote:
> Noise is measured in volts per root Hz. To get the noise over a
> bandwidth, you multiply by the square root of the bandwidth. So using
> a 10% narrower filter reduces the noise by 4.8%. So narrowing the
> bandwidth helps, but it is not a cure.
>
> The ALA100 has the advantage of receiving the magnetic portion of the
> wave, so there is less electrical noise.
Less local electrical noise. Far field is 50 - 50 magnetic and electric
fields.
> On MW, you get a figure 8 pattern, and subjectively a rather fat
> figure 8. The null is plenty sharp, but very narrow.
Translation it is pretty much non-directional.
> In antenna analysis, you need to be aware of both gain and aperture.
> Think of the photographic analogy. Antenna gain is like the focal
> length of the lens. Aperture is well "doh!" the aperture.
This is more than an analogy. This is the same type of energy. Light and
far field radio waves are EM waves. The energy is carried by photons.
> The RF field is generally volts per meter. So obviously, more is more
> if the antenna is receiving more signal and not more noise. To be
> really accurate here, the noise figure of the amp is also part of the
> equation. But once you have enough wire in tne air that the noise of
> the amp is swamped by the signal from the antenna, I'm not sure there
> is much to gain.
Antennas can show gain in one direction like a Yagi antenna for example
that can be pointed in the direction of a signal. Here the antenna will
show a gain of that signal relative to signals and noise in all other
directions so not only do you get a boost of the desired signal at the
expense of other signals you get a reduction of the far field noise over
what a nondirectional antenna would provide.
> The notion of aperture is more easily seen in VHF on up. That is, two
> meters seems to go further than 440. Well, if the antenna is the same
> design, the 440Mhz antenna has less aperture than the 2 meter antenna,
> even though the gain is the same. For 440Mhz to compete with 2 meters,
> you would need to go to a colinear with 3 elements.
Another phrase for aperture used in antennas is capture area. As you
have found out this is really important on received signal strengh.
> My guess would be going with multiple loop antennas would be superior
> to longer longwires. Now here is where you would have to check my
> math, but the two loops in parallel (summed after the ALA100 amp of
> course) would have 3db less noise. The signal would be stronger as
> well, but I think that would be counting the improvement twice. The
> stronger signal would only be significant if the noise floor of the
> radio was an issue.
Using a phase control unit between the two loop antennas would create a
high gain receive lob antenna pattern that you could steer like the Yagi
antenna example with the same benefits described above.
--
Telamon
Ventura, California
Telamon
<7b41cb3d-d6d5-407c...@f47g2000hsd.googlegroups.com>,
pli...@telkomsa.net wrote:
Yeah, this should be an exciting week.
I didn't mean to convey the impression that DSP receivers are just no
good. My RX340 sounds just fine but I prefer the sound of the R8B for AM
signals. The RX340 works really well on SSB but this is different
program material than what is on AM mode the broadcasters use.
No question that DSP is the way to go on digital signals as the software
filters are much faster, sharper, and deeper than the analog and so you
can get much better error rate ratio.
I think DSP is clearly better for SSB voice also but when it comes to
listening to AM mode broadcast that's where it has some drawbacks and
these can be minimized but they are not going to be biased that way in a
ham transceiver where the emphasis is on SSB.
I think that a really good sounding DSP receiver for AM broadcast can be
made if it is designed with that mode in mind.
--
Telamon
Ventura, California
Pete KE9OA
channel spatter can seemingly obliterate weaker stations. I think this is a
function of the AGC recovery time. Even though there are selectable AGC
rates on the Drake receivers, I think a longer than usual decay time could
cause this problem. Another thing that can cause the effect is having early
stages in a receiver generate the AGC voltage. This is not
good.............you need to have all AGC voltages generated by stages that
follow the high selectivity portions of the receiver. I found this out the
hard way, in my early receiver design days.
I don't notice this effect with the Drake R7 receiver or the TR7
transceiver. These receivers don't have the smooth, swirly audio / AGC
characteristic of the R8 either. This characteristic is what gives the R8
its pleasant audio recovery.
As a final example, the Icom R75 is very good when it comes to demodulating
a weak signal next to a very strong adjacent channel
signal..................the problem here is that its hard AGC characteristic
gives me what I would refer to as earstrain. Just not very pleasant to
listen to over long periods of time. A decay characteristic of 150 to 200
milliseconds seems to be a good compromise.
I've never played with R&S receivers, but I have played with Racal, Harris,
Collins, Cubic, etc. All of these receivers are designed for life and death
situations, and they all seem to handle that adjacent channel issue very
well.
Pete
<pli...@telkomsa.net> wrote in message
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