Re: Plugging the PL-360 7.5" Loopsticks Into the Tecsun PL...


pianoplayer88key
 

Interesting.  My PL-380 only indicates up to 63dBu for some reason.  Also you didn't say what your RSSI readings with the stock antenna are when you tune about 15, 20, or 25 kHz off of KSUH's frequency while aiming the (stock) antenna at their transmitter, and last I checked the group's search function doesn't work properly so I don't think I could find your post in which you said what KSUH's barefoot on-frequency RSSI reading was.

My strongest daytime pests (all readings in 1kHz mode) include:

 600 KOGO  5.000kW -  7.69mi, 249.21° ; 63,25 facing, 43,25 null ; 30dBu @ 580, 42dBu @ 614 (IBOC)
 690 XEWW 77.500kW - 24.62mi, 199.63° ; 63,25 facing, 46,25 null ; 34dBu @ 705 (slight splatter +/-10kHz - splatter comments are when facing station)
 760 KFMB  5.000kW -  7.29mi, 320.85° ; 63,25 facing, 46,25 null ; 34dBu @ 775 (moderate to somewhat heavy splatter +/-10kHz)
 910 KECR  5.000kW -  9.39mi,   7.15° ; 63,25 facing, 43,25 null ; 34dBu @ 775 (somewhat heavy splatter on 910)
1130 KSDO 10.000kW -  6.34mi, 350.26° ; 63,25 facing, 40,25 null ; 45dBu @ 1145, 43dBu @ 1115 (don't know why I was able to null it so much - it's my second strongest daytime pest ... also moderate splatter on 1120)
1170 KCBQ 50.000kW -  9.35mi,   7.27° ; 63,25 facing, 53,25 null ; 43dBu @ 1185 (moderate splatter on 1180)
1210 KPRZ 20.000kW - 25.71mi, 326.14° ; 50,25 facing, 35,05 null ; 37dBu @ 1225 (included for null and off-channel readings)
1360 KLSD  5.000kW -  8.28mi, 255.34° ; 62,25 facing, 30,24 null ; 32dBu @ 1375 (semi-weak splatter on 1370)
1470 XERCN 10.00kW - 18.03mi, 182.86° ; 55,25 facing, 32,25 null ; 30dBu @ 1485 (moderate to slightly heavy splatter on 1480)

I can get 1kW stations at a distance of 194.9mi on 1490 (15,11) and 1340 (22,00), a 500-watt on 1290 (24,00) same distance and a 2.5kW on 1250 at 201.08mi, though.  That is after briefly tilting the radio vertical to reduce the signal strength, THEN aiming the antenna to try for best reception.  (I find that sometimes helps tame the elevated RSSI a little, but it's still not good enough for some stations I want to hear.)  I should mention that those are Santa Barbara stations.... and since they're mostly across a salt water path (Pacific Ocean) due to the curve of the coastline, do they count as TPs? ;)

However, I can't get a 5kW at 88.28mi on 1480, a 5kW on at 94.31mi on 1350, a 50kW at 237.01mi on 1180, a 10kW at 80.77mi on 1140, a 5kW at 80.17mi on 920, or a 2.5kW at 92.85mi on 590.  I also have serious trouble with a 50kW at 111.43mi on 1110 - the signal is very faint under a 41dBu RSSI reading.
On the other hand, though, I have, with the Select-A-Tenna (all others listed up to now are barefoot), pulled in a 50kW at 445.42mi on 680 and at 625.88mi on 700.  Also, when I'm in a car (which nulls the RF across the band), I can get up to a 18dB SNR on a station on 1550 that indicates a 15dBu RSSI.

I think I remember you said in a previous post that you thought my PL-380 may be defective.  I think it's been too long for Joyce to exchange it with another unit, so what would you recommend?  I'd like to be able to get something that will fit in my pants pocket without the antenna protruding on which I can hear stations on 920, 1140, 1180 just to name a few, without splatter from locals mentioned above on the adjacent channels (910, 1130, 1170).

My original purpose for getting an ultralight recommended/recognized by the group was so I could have a radio in my pocket (the antenna would have to fit in there too) that would hear a decent signal (preferably at least 20-25dB SNR) on 1110 KDIS.  My previous radio's selectivity was horrible and had absolutely NO chance with mega-pest 1130 KSDO, and even if KSDO was off the air, KDIS would be barely readable, and probably almost stomped on by giga-pest 1170 KCBQ.  Also, upon reading the glowing reviews of the selectivity on the PL-380, I was hoping I would be able to get the station on 1180 without splatter from the local 50kW on 1170 as well, but unfortunately it seems the PL-380 has some shortcomings, as it appears (to me) Rick Robinson pointed out in his post, that I'm having a hard time overcoming.
Now I wouldn't mind having a radio in the size of the PL-380's cabinet, but would prefer that it be oriented VERTICALLY instead of horizontal.  If something existed that was that size, would there be enough room to put a good front-end tuned circuit or two in there (or whatever it would take) to help with the overload/image rejection, and still have the selectivity of the Si4734 radios?  Also I wonder how the sensitivity would be if it had a 0.5" Amidon-61 loopstick taking up the entire width of the cabinet...




--- In ultralightdx@..., D1028Gary@... wrote:
>
> Hi Stephen,
>
> Thanks for your question. KSUH-1450 is the most troublesome pest here,
> although the IBOC monstrosity KHHO-850 comes in a close second.
>
> When the 7.5" plug-in loopstick PL-380 is tuned to 1450 kHz and pointed at
> KSUH, the daytime RSSI reading here is 87, and the S/N reading is 25. When
> the loopstick nulls the pest on 1450, the readings drop to 61/25. For
> daytime DX, the hot-rodded PL-380 has no trouble limiting the KSUH splatter to
> 1442-1458 kHz when the station is nulled, and can easily receive KARR-1460
> in Kirkland, WA (a 5 KW station about 45 miles from here) in the KSUH null,
> with an additional trace of KUTI in Yakima (5 KW at about 120 miles).
>
> The PVC Loops (and other tuned passive systems) have a tuning capacitor
> which provides additional selectivity to help cut down local splatter-- a big
> advantage rarely mentioned by those promoting hard-wired air core loops
> without this benefit. For this reason, the PVC loops (both portable and
> fixed) can combine altazimuth nulling with an additional tuned circuit, cutting
> down local splatter more effectively than the nulling action of a loopstick
> alone.
>
> Despite this (in answer to your question), receiving Trans-Pacific DX on
> 1449 kHz or 1458 kHz is unlikely in a location like Puyallup, no matter which
> antenna is used. There is no TP station on either frequency strong enough
> to break through the KSUH hash, on those frequencies. In order to receive
> TP-DX on a noisy frequency, you need a fairly strong signal from Asia. Just
> like in domestic DX, you can null a pest to your heart's content, but that
> won't get you a new logging. Your antenna needs to be sensitive enough to
> dig out a DX station in the null of the pest, and in the case of 1449 and
> 1458 kHz in Puyallup, that's highly unlikely. The best I've managed with the
> 9' PVC loop here in Puyallup was a reception of 819-Pyongyang (North Korea)
> in the null of semi-local 820-KGNW (50 KW at about 20 miles), primarily
> because of an ideal combination of optimum null angle and freakish DX station
> strength. The strength of the DX station is the most important factor in
> your odds of success, when chasing DX only 1 kHz away from a pest.
>
> 73, Gary
>
>
> In a message dated 7/14/2010 1:38:47 P.M. Pacific Daylight Time,
> pianoplayer88key@... writes:
>
>
>
>
> For me, one ultimate test of external antennas is how well do they do when
> near very strong signals. For example, I believe you are
> about 2-3 miles from 1450 KSUH's transmitter, and it splatters across a
> few hundred kHz on radios with poor selectivity.
> When you use the external antennas (whether they're the PVC loops or the
> large loopsticks) with the Tecsun (or other) DSP-based radios, how close can
> you get to the local station's frequency and still have a chance at
> logging DX? For example, I believe 1449 is a split channel frequency - can you
> get anything on that frequency without 1450 bleeding through? Or, are you
> close enough to 1450 so that even without an external antenna you're getting
> 50dBu readings in blank channels across a portion of the band?
>
> --- In _ultralightdx@... (mailto:ultralightdx@...)
> , D1028Gary@ wrote:
> >
> > Hi Richard,
> >
> > It's true that for the barefoot PL-310 and PL-380 models, there is a
> > tradeoff in AM sensitivity and soft mute inconvenience, which makes the
> > purchasing decision quite interesting (fully described in the PL-380
> review, which
> > is posted at __http://www.mediafire.com/?w4yuzhj2kyz__
> (http://www.mediafire.com/?w4yuzhj2kyz_)
> > (_http://www.mediafire.com/?w4yuzhj2kyz_
> (http://www.mediafire.com/?w4yuzhj2kyz) ) ). But for the 7.5" plug-in loopstick project, all the
> > advantages would swing over to the PL-380 model. The upgrade loopsticks
> > provide a huge boost in the PL-380's AM and LW sensitivity, and the soft
> mute
> > inconvenience is less, allowing the innovative Si4734 model to be used
> to
> > its full DXing potential.
> >
> > In answer to your question, a PL-310 could certainly be modified to
> accept
> > these 7.5" plug-in loopsticks (with the FM and SW input jack left
> intact),
> > but there would be more soft mute hassle than with the PL-380.
> >
> > The newly-modified PL-380 model was tested with the experimental LW 7.5"
>
> > plug-in loopstick here last night (photo below, and at
> > __http://www.mediafire.com/?ditdm4ym2g25k5m__
> (http://www.mediafire.com/?ditdm4ym2g25k5m_) (_http://www.mediafire.com/?ditdm4ym2g25k5m_
> (http://www.mediafire.com/?ditdm4ym2g25k5m) ) ), and
> > it was giving the stock ICF-2010 stiff competition on the lower LW
> > frequencies. When these 7.5" plug-in LW and AM loopsticks are used with
> the PL-380
> > model, Richard, the DXer can have excellent DX, freedom and convenience
> on
> > both bands-- the main reason that this new project was completed before
> my
> > family's Oregon beach vacation next week :-)
> >
> > 73, Gary
> >
> >
> >
> >
> >
> > In a message dated 7/14/2010 6:57:18 A.M. Pacific Daylight Time,
> > farmerik@ writes:
> >
> >
> >
> >
> > When I compared the 380 and 310 from your reviews, I chose the more
> > sensitive 310, even though the 380 does have less muting problems. So I
> will be
> > interested in a 380 modified to use the external loop sticks you make,
> > including the forthcoming LW version.
> >
> > Will you be leaving the FM and SW input jack intact, so I can use that
> > too? - FARMERIK
> >
> > --- In __ultralightdx@...
> (mailto:_ultralightdx@...) _ (mailto:_ultralightdx@...
> (mailto:ultralightdx@...) )
> > , D1028Gary@ wrote:
> > >
> > > Hi Farmerik,
> > >
> > > Mouser Electronics has supplied me with high quality electronic parts
> > for
> > > years, and they have a great variety of components. I should have used
> a
> >
> > > high quality plug-in jack from them instead of the Radio Shack type,
> but
> > this
> > > entire project was kind of a spur-of-the-moment effort to prove to
> > myself
> > > that the PL-380 cabinet modification mechanical design was viable, and
> > the
> > > mechanical design was about 90% of the challenge in this case.
> > >
> > > After refinement of the components and procedures, this PL-380 plug-in
> > > loopstick project should provide another way for non-technical DXers
> to
> > enjoy
> > > thrilling transoceanic DX, this time on a receiver with the full
> > > capabilities of the Si4734 DSP chip. Have fun!
> > >
> > > 73, Gary
> > >
> > >
> > > In a message dated 7/13/2010 5:24:44 P.M. Pacific Daylight Time,
> > > farmerik@ writes:
> > >
> > >
> > >
> > >
> > > Many years ago, I liked Switchcraft jacks and plugs, I don't know if
> > they
> > > still make them. Where would you recommend to buy quality jacks and
> > plugs,
> > > or what brands should I look for?
> > > I would like to add 1/8th inch phone jacks which will bypass the
> > internal
> > > loop sticks in my larger radios, if I can do it. Maybe I should go
> with
> > 1/4
> > > inch though.
> > > With help from a member here, I am working on a version of Jim's Hoop
> > > Loop.-FARMERIK
> > >
> > > --- In ___ultralightdx@...
> (mailto:__ultralightdx@...) _
> > (mailto:__ultralightdx@...
> (mailto:_ultralightdx@...) ) _ (mailto:__ultralightdx@...
> (mailto:_ultralightdx@...) _
> > (mailto:_ultralightdx@...
> (mailto:ultralightdx@...) ) )
> > > , D1028Gary@ wrote:
> > > >
> > > > Hello All,
> > > >
> > > > For those interested in weird loopstick experimentation, a Tecsun
> > PL-380
> > > > model has been successfully modified to accept the 7.5" plug-in
> > > loopsticks
> > > > (AM and LW) developed for the PL-360 model.
> > > >
> > > > Using a strange collection of plastic parts and dubious Radio Shack
> > > > components, a small "docking port" was designed and assembled for
> > > attachment to
> > > > the top of the PL-380 cabinet, using the same "rubber lock" shock
> > > absorbing
> > > > system that has proven successful in the PL-360 7.5" loopstick
> models.
> > > In
> > > > the case of the PL-380, however, there is no whip antenna tip (or
> > > antenna
> > > > plug-in jack) that can be used for mounting the 7.5" loopsticks-- so
> > > both had
> > > > to be designed from scratch.
> > > >
> > > > A .25" O.D. 1" long section of a Levelor blind plastic wand served
> > > nicely
> > > > as the loopstick frame rubber hose mount, and a Radio Shack 1/8"
> phone
> > > jack
> > > > (part number 274-0248) served not-so-nicely as the plug-in jack,
> > mainly
> > > > because of the cheap quality of the material. Both were secured in
> > > vertical
> > > > holes drilled in a cut-up section of a Swanson Level Square, glued
> to
> > > the top
> > > > of the PL-380 cabinet. Various photos of this fanatical contraption
> > will
> > > > be uploaded to the Ultralightdx photos section, in a new file.
> > > >
> > > > The original design had the stock loopstick antenna in-circuit
> > whenever
> > > > the 7.5" plug-in antenna was unplugged, meaning that either antenna
> > > could be
> > > > used as desired. This system actually worked for a while, until the
> > > > temperamental Radio Shack plug-in jack decided to go on strike (a
> > > mechanical
> > > > connection issue), making me wonder why I ever used it in the first
> > > place.
> > > > Eventually I decided to disconnect the stock loopstick, and use only
> > the
> > > 7.5"
> > > > plug-in loopstick, which has always worked perfectly in this weird
> > > experimen
> > > > t. The PL-380 DXing performance with this 7.5" plug-in loopstick is
> > > > equivalent to that of the fixed-frame 7.5" loopstick PL-380's, which
> > was
> > > the goal
> > > > of the project.
> > > >
> > > > Because of the low quality of the Radio Shack phone jack and some
> > other
> > > > mechanical refinements that would optimize this project, it would be
> > > best not
> > > > to take orders for similar PL-380 cabinet modifications until these
> > > > improvements are made. For those 22 DXers who have already received
> > > their PL-360
> > > > 7.5" plug-in loopsticks, however, this project may eventually
> provide
> > a
> > > way
> > > > to enjoy great transoceanic AM (and LW) DX on the PL-380 model--
> > simply
> > > by
> > > > plugging in their existing 7.5" loopsticks.
> > > >
> > > > 73 and Good DX,
> > > > Gary DeBock (in Puyallup, WA, USA)
> > > >
> > >
> >
>

Join main@UltralightDX.groups.io to automatically receive all group messages.