Date   

Tecsun PL-360 3" Loopstick Testing

Gary DeBock
 

Hello All,
 
A medium-sized replacement loopstick for the Tecsun PL-360 was wound on a 3" x 3/8" type 61 Amidon ferrite bar, using 40/44 Litx wire at an inductance of 315 uh (which practically maxed out the length of this shorter bar, making it impractical to add more turns). The loopstick was mounted with rubber shock mounts on a cut piece of plastic carpenter's level, with a Radio Shack 1/8" phone plug to match the stock loopstick jack.
 
Live signal testing of this new loopstick confirms that it boosts the AM sensitivity of the modest PL-360 well past that of either the stock PL-310 or PL-380 on all frequencies from 530-1600 kHz, with excellent nulling qualities. Even though this loopstick is much shorter than the 7.5" long model tested yesterday, it apparently is a huge improvement over any of the stock loopsticks used by Tecsun, and thereby outperforms all of them on the AM band.
 
The total cost of this loopstick upgrade is about $15 in parts, a real bargain considering the increase in AM-DXing capability.
 
73, Gary DeBock (in Puyallup, WA)
 
 
 
                                         


Re: Tecsun PL-360 Plug-in Loopsticks-- Huge AM Sensitivity...

Gary DeBock
 

Hello Jeff,
 
Thanks for your interest in the Tecsun PL-360 model.
 
The FM and SW reception capabilities of the PL-360 fall somewhat short of the PL-310 and PL-380 models because of the shorter (by 3") whip antenna. As an Si4734-chip based radio the PL-360 still does have above-average FM reception for its size, however, especially in comparison to non-DSP portables. A detailed "Shootout" on FM and SW will be included in the upcoming PL-360 review, which will give a thorough comparison with these other Tecsun models to benefit potential purchasers.
 
The PL-360 does not have LW coverage or the numeric keypad of the other models, and the fixed 3 kHz DSP selectivity follows the design of the PL-300WT/ G8 units. Except for the plug-in loopstick design the radio would be quite ordinary, but the opportunity to plug in highly sensitive AM replacement loopsticks without any radio modification is unique among the DSP Ultralights. A huge AM sensitivity boost can certainly compensate for a multitude of other shortcomings, especially when the radio is so compact and user-friendly. With a 7.5" loopstick the PL-360 can provide enough thrills to satisfy almost any domestic DXer. 
 
73, Gary DeBock (in Puyallup, WA)    
 
 
 

In a message dated 4/12/2010 10:58:53 P.M. Pacific Daylight Time, jeff@... writes:
 



Knowing that mw can be quite good with this little radio, how is fm and sw reception? How does it compare to the 310 and 380 as well as any other small and portable Eton or Degen receivers? It sure looks like an ideal "carry everywhere you go" radio. I have the Degen 1105, Grundig G6, and Eton 100 for small, all around portables along with the Grundig G8. The 360 could be a great addition.
Jeff

--- In ultralightdx@yahoogroups.com, D1028Gary@... wrote:
>
> Hello All,
>
> The Tecsun PL-360 is one of the smallest Si4734 DSP-chip Ultralights, with
> a rather modest stock loopstick. It has fixed 3 kHz DSP selectivity, and
> fully enabled soft mute-- similar to the Tecsun PL-300WT/ Grundig G8 models.
> But is does one have one stellar quality that is unique among the DSP
> Ultralights produced so far-- the loopstick is of a plug-in variety, using a
> standard RCA phono plug. The owner can switch to an extremely sensitive 7.5"
> Amidon loopstick within a couple of seconds, without doing any "surgery" to
> the radio at all.
>
> Today the first Amidon 7.5" plug-in loopstick for the PL-360 was created
> here, and it transforms this modest radio into a extremely sensitive DX
> chaser, fully equal to the E100 Sliders, 7.5" loopstick PL-380's and other
> DXing sensations. Both sensitivity and nulling ability are the equal of any
> other modified Ultralight, and the fact that a user can obtain this massive AM
> sensitivity boost without any modification to the radio is very exciting.
> For domestic DXers who don't usually need 1 kHz DSP selectivity, this radio
> may become a dream machine.
>
> The stock 300 uh loopstick coil can easily be replaced with a plug-in
> design of the user's choice, and besides the 450 uh type 61 7.5" loopstick model
> shown, a medium-sized loopstick (on a different length of type 61 bar)
> will shortly be tested out here. The plug-in loopsticks may well make this
> model one of the most popular Ultralights for domestic DXers, and an ideal
> platform for loopstick experimentation.
>
> 73 and Good DX,
> Gary DeBock (in Puyallup, WA, USA)
>


Re: A new station this evening

Rik
 

Great catch!- FARMERIK

--- In ultralightdx@yahoogroups.com, "ferrite61" <dxrx@...> wrote:

Caught a new one for te log tonite just before local sunset. Tuning from 720 upwards I found a religious station on 750kHz at 1935 EDT. Listened for 8 minutes until fade away at 1943 EDT... just barely there another 2-3 minutes, down in the noise-floor. Reception was made using the PL310 in due E-W orientation. Very good RX of "Catholic Answers Live" program taking calls. Also many mentions of Catholic (dot) com. NoID or call-sign. Since 750kHz has limited listings, I looked this up on AMLogBook, and found that WQOR Olyphant, PA is very well matched being an EWTN affiliate. WQOR is Day-only ND and FCC look-up indicates 271 degrees reletive at 215 km. Power is listed at 1600 Watts. I decided to log this as Station #425.

Paul S. in CT


Re: Georgia and South Carolina coast ulr dx sessions,part 3

ferrite61 <dxrx@...>
 

--- In ultralightdx@yahoogroups.com, "Carl" <carl_elissa@...> wrote:

Here are a few loggings from Litchfield Beach ,S.C. I did not do much dxing from there.

1620 WDHP Frederiksted ,U.S.V.I. 1945-2006 EDT Caribbean style music.i.d." You are listening to WDHP-AM..U.S. Virgin Islands.good to fair mixing with presumed Cuban and U.S. station.E-100 with SAT.
This one still eludes me after 4 years :( Being in the X-Band I always thought this an easy target, but utility noise always seems about. At Rocky Neck St. Park, its easy at dusk even on a WRX911 barefoot. Haven't gotten this inland 12 miles, though Cuba on many frequencies makes it here.

I have yet to hear this from Maryville ,Tn.
1550 Radio Rebelde Cuba 2019-2029 EDT.fair//670.E-100 barefoot.
Thanks for the tip, I usually get local Disney by day and CBE(?) at night... the Cuba station might squeeze into the CBE null.Will try for this tomorrow night if possible.

1540 ZNS-1 National Voice of the Bahamas 2029-2035 EDT. Carribean style music.i.d."Absolutely no one plays more..AM 1540,The National Voice of The Bahamas"fair-good.E-100 barefoot.
Too much Canada and WDCD, always trying for this one here, and have gotten this at RNSP.

Paul S. in CT comments

In all 7 countries were logged in 3 nights on this vacation.
Carl DeWhitt
Maryville ,Tn.


A new station this evening

ferrite61 <dxrx@...>
 

Caught a new one for te log tonite just before local sunset. Tuning from 720 upwards I found a religious station on 750kHz at 1935 EDT. Listened for 8 minutes until fade away at 1943 EDT... just barely there another 2-3 minutes, down in the noise-floor. Reception was made using the PL310 in due E-W orientation. Very good RX of "Catholic Answers Live" program taking calls. Also many mentions of Catholic (dot) com. NoID or call-sign. Since 750kHz has limited listings, I looked this up on AMLogBook, and found that WQOR Olyphant, PA is very well matched being an EWTN affiliate. WQOR is Day-only ND and FCC look-up indicates 271 degrees reletive at 215 km. Power is listed at 1600 Watts. I decided to log this as Station #425.

Paul S. in CT


Georgia and South Carolina coast ulr dx sessions,part 3

Carl DeWhitt
 

Here are a few loggings from Litchfield Beach ,S.C. I did not do much dxing from there.

1620 WDHP Frederiksted ,U.S.V.I. 1945-2006 EDT Caribbean style music.i.d." You are listening to WDHP-AM..U.S. Virgin Islands.good to fair mixing with presumed Cuban and U.S. station.E-100 with SAT.
I have yet to hear this from Maryville ,Tn.
1550 Radio Rebelde Cuba 2019-2029 EDT.fair//670.E-100 barefoot.
1540 ZNS-1 National Voice of the Bahamas 2029-2035 EDT. Carribean style music.i.d."Absolutely no one plays more..AM 1540,The National Voice of The Bahamas"fair-good.E-100 barefoot.
In all 7 countries were logged in 3 nights on this vacation.
Carl DeWhitt
Maryville ,Tn.


Re: Tecsun PL-360 Plug-in Loopsticks-- Huge AM Sensitivity...

Gary DeBock
 

Hello Farmerik and Fernando,
 
Thank you for your interest in this PL-360 plug-in loopstick project, which seems like an ideal way for a DXer to get a huge AM sensitivity boost without even opening up the DSP's radio's cabinet.
 
In answer to your question, Farmerik, since I doubt that Tecsun (or Anon-co) will ever offer one of these 7.5" plug-in loopsticks as an accessory :-), I would be happy to make up a few of these for you and other deserving DXers, as time allows. Thanks also for your private message.
 
For those interested in making their own, my own procedure is to cut a horizontal piece of a 48" carpenter's level to the desired length, then drill a 3/8" perpendicular hole in it through the center section. This will accommodate the 1/8" phone plug housing (sold by Radio Shack in a package of 2, for $3) very securely in the plastic piece, especially when superglue is used. I recommend the plastic-housed 1/8" phone plug connectors (either black or red-colored, with soldering terminals) rather than the metal type, to avoid having any metallic conductors near the 40/44 Litz wire (which may skew the nulling pattern). This maintains an all-insulating plastic and rubber frame for the loopstick, for maximum DXing performance. As pointed out by Farmerik, the plug type is indeed a 1/8" (head)phone plug type, and not an RCA phono plug.
 
Another shorter PL-360 plug-in loopstick using 40/44 Litz wire on an Amidon 3" x 3/8" type 61 ferrite bar will soon be tested here, and my guess is that even this shorter loopstick will have a significant AM sensitivity advantage over both the stock PL-310 and PL-380. As might be expected, the 7.5" plug-in loopstick in the PL-360 really "smokes" both stock models. All things considered, it's not bad for a "no surgery" modification costing about $25 in parts.
 
73 and Good DX,
Gary DeBock (in Puyallup, WA, USA)
 
 
      
 
 

In a message dated 4/12/2010 1:03:58 P.M. Pacific Daylight Time, fernandocano@... writes:
 


i will buy one

-----Original Message-----
From: farmerik
Sent: Apr 12, 2010 2:10 PM
To: ultralightdx@yahoogroups.com
Subject: [ultralightdx] Re: Tecsun PL-360 Plug-in Loopsticks-- Huge AM Sensitivity Boosts

 

IT WORKS!!!!

Now, who wants to wind and sell plug in ferrite antennas for the fumble fingered? - FARMERIK

--- In ultralightdx@yahoogroups.com, D1028Gary@... wrote:
>
> Hello All,
>
> The Tecsun PL-360 is one of the smallest Si4734 DSP-chip Ultralights, with
> a rather modest stock loopstick. It has fixed 3 kHz DSP selectivity, and
> fully enabled soft mute-- similar to the Tecsun PL-300WT/ Grundig G8 models.
> But is does one have one stellar quality that is unique among the DSP
> Ultralights produced so far-- the loopstick is of a plug-in variety, using a
> standard RCA phono plug. The owner can switch to an extremely sensitive 7.5"
> Amidon loopstick within a couple of seconds, without doing any "surgery" to
> the radio at all.
>
> Today the first Amidon 7.5" plug-in loopstick for the PL-36 0 was created
> here, and it transforms this modest radio into a extremely sensitive DX
> chaser, fully equal to the E100 Sliders, 7.5" loopstick PL-380's and other
> DXing sensations. Both sensitivity and nulling ability are the equal of any
> other modified Ultralight, and the fact that a user can obtain this massive AM
> sensitivity boost without any modification to the radio is very exciting.
> For domestic DXers who don't usually need 1 kHz DSP selectivity, this radio
> may become a dream machine.
>
> The stock 300 uh loopstick coil can easily be replaced with a plug-in
> design of the user's choice, and besides the 450 uh type 61 7.5" loopstick model
> shown, a medium-sized loopstick (on a different length of type 61 bar)
> will shortly be tested out here. The plug-in loopsticks may well make this
> model one of the most popular Ultralights for domestic DXers, and an ideal
> ; platform for loopstick experimentation.
>
> 73 and Good DX,
> Gary DeBock (in Puyallup, WA, USA)
>


Re: Tecsun PL-360 Plug-in Loopsticks-- Huge AM Sensitivity Boosts

fernandocano@...
 


i will buy one

-----Original Message-----
From: farmerik
Sent: Apr 12, 2010 2:10 PM
To: ultralightdx@...
Subject: [ultralightdx] Re: Tecsun PL-360 Plug-in Loopsticks-- Huge AM Sensitivity Boosts

 

IT WORKS!!!!

Now, who wants to wind and sell plug in ferrite antennas for the fumble fingered? - FARMERIK

--- In ultralightdx@yahoogroups.com, D1028Gary@... wrote:
>
> Hello All,
>
> The Tecsun PL-360 is one of the smallest Si4734 DSP-chip Ultralights, with
> a rather modest stock loopstick. It has fixed 3 kHz DSP selectivity, and
> fully enabled soft mute-- similar to the Tecsun PL-300WT/ Grundig G8 models.
> But is does one have one stellar quality that is unique among the DSP
> Ultralights produced so far-- the loopstick is of a plug-in variety, using a
> standard RCA phono plug. The owner can switch to an extremely sensitive 7.5"
> Amidon loopstick within a couple of seconds, without doing any "surgery" to
> the radio at all.
>
> Today the first Amidon 7.5" plug-in loopstick for the PL-360 was created
> here, and it transforms this modest radio into a extremely sensitive DX
> chaser, fully equal to the E100 Sliders, 7.5" loopstick PL-380's and other
> DXing sensations. Both sensitivity and nulling ability are the equal of any
> other modified Ultralight, and the fact that a user can obtain this massive AM
> sensitivity boost without any modification to the radio is very exciting.
> For domestic DXers who don't usually need 1 kHz DSP selectivity, this radio
> may become a dream machine.
>
> The stock 300 uh loopstick coil can easily be replaced with a plug-in
> design of the user's choice, and besides the 450 uh type 61 7.5" loopstick model
> shown, a medium-sized loopstick (on a different length of type 61 bar)
> will shortly be tested out here. The plug-in loopsticks may well make this
> model one of the most popular Ultralights for domestic DXers, and an ideal
> platform for loopstick experimentation.
>
> 73 and Good DX,
> Gary DeBock (in Puyallup, WA, USA)
>


Re: Tecsun PL-360 Plug-in Loopsticks-- Huge AM Sensitivity Boosts

Rik
 

IT WORKS!!!!

Now, who wants to wind and sell plug in ferrite antennas for the fumble fingered? - FARMERIK

--- In ultralightdx@yahoogroups.com, D1028Gary@... wrote:

Hello All,

The Tecsun PL-360 is one of the smallest Si4734 DSP-chip Ultralights, with
a rather modest stock loopstick. It has fixed 3 kHz DSP selectivity, and
fully enabled soft mute-- similar to the Tecsun PL-300WT/ Grundig G8 models.
But is does one have one stellar quality that is unique among the DSP
Ultralights produced so far-- the loopstick is of a plug-in variety, using a
standard RCA phono plug. The owner can switch to an extremely sensitive 7.5"
Amidon loopstick within a couple of seconds, without doing any "surgery" to
the radio at all.

Today the first Amidon 7.5" plug-in loopstick for the PL-360 was created
here, and it transforms this modest radio into a extremely sensitive DX
chaser, fully equal to the E100 Sliders, 7.5" loopstick PL-380's and other
DXing sensations. Both sensitivity and nulling ability are the equal of any
other modified Ultralight, and the fact that a user can obtain this massive AM
sensitivity boost without any modification to the radio is very exciting.
For domestic DXers who don't usually need 1 kHz DSP selectivity, this radio
may become a dream machine.

The stock 300 uh loopstick coil can easily be replaced with a plug-in
design of the user's choice, and besides the 450 uh type 61 7.5" loopstick model
shown, a medium-sized loopstick (on a different length of type 61 bar)
will shortly be tested out here. The plug-in loopsticks may well make this
model one of the most popular Ultralights for domestic DXers, and an ideal
platform for loopstick experimentation.

73 and Good DX,
Gary DeBock (in Puyallup, WA, USA)


Re: question about Grundig G8 volume

jim_kr1s <jkearman@...>
 

Clarence,

This should explain it: http://en.wikipedia.org/wiki/Rotary_encoder 

The major consumer portable manufacturers have been slow to adopt DSP. Sony, which once led the way with synchronous detection, has practically fallen off the planet. Japanese amateur radio equipment incorporates DSP, but the other guys haven't caught on. We're all waiting for the Next Big Thing from China, which is using DSP chips made right here in the U.S.A.

73,

Jim, KR1S
http://kr1s.kearman.com/ 


Welcome to Cycle 24

jim_kr1s <jkearman@...>
 

The sun's at us again. Some of us complained about the duration of the last solar minimum. Now the sun's telling us, I'm ba-a-a-a-ck! After one peaceful day we had a G3-level storm yesterday, and a G2 is predicted for today. Disturbed conditions can do wonders on LW, just as on MW, if the DXer is disturbed enough to endure them. I'd been hunting for a NDB in Georgia, to add  that scalp to my belt. While tuning around last night I heard the faintest whisper of Morse Code under the static crashes, and finally copied the call. It was a 25-watt beacon about 430 miles NW of me. That's like hearing a 50-kW station 860,000 miles away! It took the larger loop, though; that station was inaudible on the Hoop Loop. (My hands are arthritic, my eyesight is shot, but I can still dig out weak CW signals.)

Another one I needed finally made it to the log last night, too: Cuba! They obviously blew all their radio resources on AM broadcast stations. That beacon was still good copy on the Hoop Loop this morning, so don't know how I missed it before now. For you history buffs, Zaragoza is where Jose Marti went to law school. Other than one more inland Georgia NDB this morning, and another SC NDB last night (both logged with the Hoop Loop), LW was pretty flat. Once again, only R Europe 1 on 183 kHz was strong enough to listen to last night, but they (and everything else on the band) were getting clobbered by static crashes. (The nearest line of thunderstorms I could find last night was right along the Rio Grande, but the crashes were louder than all but the closest beacons. There's a lot of power in a thunderstorm!)

Tally now is 13 LW countries, and a whopping 4 LW states! Today's date.

UTC

kHz

Call

City

S/P/C

0240

245

JYL

Sylvania

GA

0253

283

UZG

Zaragoza

Cuba

0305

248

FRT

Spartanburg

SC

0930

353

VV

Greensboro-Junne

GA



73,

Jim, KR1S
http://kr1s.kearman.com/ 


question about Grundig G8 volume

Lst.Servs
 

Hi Everyone,

I have a Grundig G8 and I really like the volume control. I don't know
what it's called (that's my question actually). It's a rotary wheel that
doesn't stop, IMHO an outstanding feature, as it doesn't develop dead
spots at really low volumes like a knob that has a positive stop.

I have an ATS-909 right next to it, my favorite radio, but within a year
the volume got a bit dodgy so it goes from near silence to too loud with
no adjustment in between, so won't work as a bedside radio if my wife's
in bed.

So... what do you call that kind of volume control? Anyone know if any
Sangean models use this? Would like my next radio to be bedside Sangean
super AM DX-er with DSP and this type of volume control (and optionally
lighted button controls, as long as I'm sharing my wish list).

Thanks in advance,

Clarence


Re: Winding toroids, etc.

jim_kr1s <jkearman@...>
 

Hi, Steve,

Yes, I used a bobbin. Various physical limitations due to age, make it take a little longer. The worst part was making sure the #24, which is fairly stiff, was snug all the way 'round. It took a few aspirins to get my fingers uncurled. A LW coil that big is overkill on a PL-380, but I had to find out. A 140 wound with #28 seems to work just as well.

73,

Jim, KR1S
http://kr1s.kearman.com/ 


Re: Winding toroids, etc.

Steve Ratzlaff <steveratz@...>
 

Hi Jim,
I wind a lot of toroids and use a homemade bobbin to wind anything that has more than about 20 turns. The larger the core the larger and longer the bobbin--for that big 240 core something like a 3-4 inch bobbin would work great and I bet would take well under 10 minutes to wind. Some of the half inch and under toroids are hard to wind using a bobbin that small, but usually don't take more than 20-25 turns, so doing them by hand isn't much of a problem.
73,
Steve AA7U
NE Oregon

----- Original Message -----
From: jim_kr1s
Sent: Sunday, April 11, 2010 6:54 PM
Subject: [ultralightdx] Re: Why are some radios so directional?- FARMERIK


--- In ultralightdx@..., "sdwillingham" wrote:
>
> Thanks for the kitsandparts link! I've been struggling to find a good source for toroids and wire at reasonable prices.

MW and LW take a lot more wire than HF. I recommend buying the stuff in 1-lb spools. I want one of those machines that winds them! Stuffing 125 turns of #24 on that FT240-61 the other day did it for me for a while.

73,

Jim, KR1S
http://kr1s.kearman.com/ 


Re: Why are some radios so directional?- FARMERIK

jim_kr1s <jkearman@...>
 


--- In ultralightdx@..., "sdwillingham" wrote:
> If you wish to Google for more information, try searching for direction-finding antennas.

I've been living in that world the last several weeks. At this site, http://www.tubebooks.org/technical_books_online.htm  you can download two older books on the subject,  Aeronautical Radio, by Myron Eddy, pub. 1939, and a shorter book, D/F Handbook for Wireless Operators, by  W. E. Crook, pub. 1942. The latter book probably has all you need to know. Terman's Radio Engineers' Handbook, published during WW2, has more theory if you're interested. There's good info in Terman on MW and LW propagation, and some of the anomalies we run into, also. You usually can find inexpensive copies on the auction site. There was another book with the same title by Keith Henney; you want the Terman.

73,

Jim, KR1S
http://kr1s.kearman.com/ 


Re: Why are some radios so directional?- FARMERIK

jim_kr1s <jkearman@...>
 


--- In ultralightdx@..., "sdwillingham" wrote:
>
> Thanks for the kitsandparts link! I've been struggling to find a good source for toroids and wire at reasonable prices.

MW and LW take a lot more wire than HF. I recommend buying the stuff in 1-lb spools. I want one of those machines that winds them! Stuffing 125 turns of #24 on that FT240-61 the other day did it for me for a while.

73,

Jim, KR1S
http://kr1s.kearman.com/ 


Re: Why are some radios so directional?- FARMERIK

jim_kr1s <jkearman@...>
 

Thanks for the info! I hope to avoid starting a collection but the 790 looks interesting. All of those old sets had 455-kHz IFs and so-so image rejection. I think the next one is going to be homebrew.

73,

Jim, KR1S
http://kr1s.kearman.com/ 


ULR DX.....Sunset Skip....1 NEW STN and a CALL CHANGE

robert ross
 

Hi Guys:

Well...I'm still squeezing the guts out of what's left of the AM BCB Season. Tonight at Sunset Skip I logged ONE NEW STATION, and a RELOG CALL CHANGE. So...even though it's getting noisier and the band is hurting...there is still a few things breaking through the static.

The New Station is NEW for both the OVERALL LOG and the ULR LOG. The Call Change is a RELOG CALL CHANGE for both Logs.

Radio Used is......SONY SRF-T615 ULR Barefoot
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

ULR LOG TOTALS are now....829 Stations Heard
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

73....ROB VA3SW

Robert S. Ross
London, Ontario CANADA


*******************************************************************
1220 WJUN Mexico, PENNSYLVANIA April/11/10 1919 EDT EE FAIR
Mixing with WHKW-Cleveland.Female with "ESPN Radio and ESPN Dot Com
Promos @ 1919 Tune In. Male with Sports Center Spot and Basketball
Scores @ 1920. Mix with WHKW til 1927 EDT. Back with Male talking
about Yankee Stadium @ 1927. Female with IDs as "ESPN Radio and ESPN
Dot Com". ID @ 1930 EDT as "ESPN RADIO 1220".Still mixing with Sports
Talk and ESPN IDs til 1938 EDT.

NEW STATION ULR # 829 1 KW/46 Watts Nights
ROSS, ONT.
*********************************************************************
1370 WRWD Ellenville, NY April/11/10 1950 EDT EE FAIR
Mixing with WSPD Toledo. Female with spot for "WRWD-FM Dot Com" @
1950 EDT Tune In. WRWD ID Sung Out by Females @ 1951. Into Older
Country Song by male singer @ 1951. More CW Music 1954-57.
ID at 2002 EDT as "WRWD AM Ellenville and WRWD-FM....Broadcasting
????" Into more Older CW Music @ 2002 EDT.

RELOG (CALL CHANGE) EX-WELG 5 KW Days
ROSS, ONT.
***********************************************************************


Re: Why are some radios so directional?- FARMERIK

sdwillingham
 

Thanks for the kitsandparts link! I've been struggling to find a good source for toroids and wire at reasonable prices.

-Scott-

--- In ultralightdx@yahoogroups.com, "jim_kr1s" <jkearman@...> wrote:

If you're not afraid to do some soldering inside the radio, get some
FT114-61 toroids from http://kitsandparts.com/
<http://kitsandparts.com/> , wind 55 turns (240 uH) of #24 magnet wire
(spaced over about 2/3 of the core), and then try coupling whatever
antennas suit your fancy, varying the number of turns on the coupling
loop for best results.


Re: Why are some radios so directional?- FARMERIK

sdwillingham
 

In addition to the overall shape of the antenna (length vs diameter), a big factor in creating deep nulls is the symmetry of the antenna, both physically and electrically. In addition the symmetry of the antenna's surroundings in the radio will come into play. Hence, a coil centered on its ferrite should (other factors equal) have better nulls than a non-centered coil.

An electrically balanced configuration will null better than an unbalanced configuration. The usual methods of achieving electrical balance involve differential amplifiers (common in some high-performance amplified antennas; not common inside portable radios) or using a balun transformer.

If the antenna and receiver circuit are "unbalanced", there are several factors that determine how much of an effect this has. A small (small overall ground plane and circuits) battery-powered portable can be electrically "floating" in its environment and still maintain some reasonable balance. Connecting a power adapter cord can drastically change the balance. Within the radio, the proximity of other circuits to the loopstick will influence the circuit balance.

Well, I've rambled on a bit, but this is an interesting and subtle question. If you wish to Google for more information, try searching for direction-finding antennas.

-Scott-

--- In ultralightdx@yahoogroups.com, "farmerik" <farmerik@...> wrote:

Can any of the engineers here explain why some radios are VERY directional using the internal ferrite loops?
With my PL-600 I can easily separate stations in different directions by only a fairly small number of degrees, perhaps 15 or 20, The 310 seems good at nulling stations too, and the 911 series are supposed to be very good at that also, as well as a few others. Many other radios cannot do this. I can't completely null out a station that close in direction, but I can make a target much louder than a pest, and switch back and forth between them. What ever causes this would be very good to incorporate in any external antenna designs, if possible. - FARMERIK