MW Image Discovered on E-100


Gary DeBock
 

Hello Steve,
 
     The Sangean DT-200V, DT-200VX and new DT-400W models have exceptional image rejection, and it is unlikely that you will ever hear images on stock units.  The only way I was able to hear an image on one was to hot-rod a DT-200VX with a 6.25" loopstick, making it sensitive enough to hear a weak image of my local 1450 pest on 550 (IF is 450 kHz).
 
    The E100 has no such image protection, and it readily produces images of strong locals 910 kHz below their fundamental frequencies (IF of 455 kHz).  The SRF-T615 and SRF-M37V both have images twice their 450 kHz IF's, as do the DT-210V and DT-180V models.
 
     The only image-proof (at least on MW) Ultralights are the Sony CXA1129N family of analog AM-FM portables...  the SRF-59, SRF-39FP, SRF-49, etc.  Their unique mixing scheme makes it impossible to produce images on MW frequencies-- even with monster loopsticks.  They are also generally resistant to overload-- except with monster loopsticks  :>)
 
                                                                         73,  Gary 




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Steve Ponder <n5wbi@...>
 

This evening while going through the MW band on my E-100,
I discovered an image of my local SS station on 1480 kHz
showing up on 570 kHz (2 x 455 kHz + 570 kHz = 1480 kHz).

This image did not show up on either my Sangean DT-400W or
my Sangean DT-200V. I did not try my Sony SRF-M37V.

I have noticed this before with my Radio Shack DX-399 (a
rebadged Sangean ATS-606AP) and my Grundig YB-305.

Does the circuitry of the DT-400W and the DT-200V use a
different IF frequency?

Just curious ...

Thanks & 73,

Steve N5WBI
Houston TX


bbwrwy
 

A few days ago I discovered I could hear KFXY-1640 on my E100 at 730
kHz during the day when it's running 10 kW. Thus far I've not found
another image.

Richard Allen


Gary DeBock
 

Hi Steve,
 
     Glad that the info helped.  Regarding your Toshiba portable,  the Ultralight Classifications file posted on dxer.ca can give you specific information on whether your unit may qualify as an Ultralight, and a volunteer Committee of three (Kevin Schanilec, Joe Miller and Gil Stacy) makes the final decision to approve or disapprove a model.
 
                          73,  Gary
    




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Steve Ponder N5WBI <n5wbi@...>
 

Gary,

Thanks for the great info!

The 570/1480 image problem, to the best of my knowledge, is the only
such problem I've encountered with my radios here in Houston. Looking
at KLVL-1480's antenna patterns, I see that I'm directly in their
"gun-sights" for both day and night. That may explain a lot of why
they're such a pest.

Otherwise, the E-100 has turned out to be a great little radio. I still
haven't had a lot of time to give it a full test, though. Maybe this
weekend (?).

Do you know of any ultralights that employ dual conversion on
mediumwave?

Also, I have a Toshiba RP-F11 that measures 5.1 x 3.1 x 1.1 inches
(17.391 cu. in.). Would it be considered an ultralight? A good
picture can be found at:

http://www.universal-radio.com/used/UP86lrg.jpg

73 & GREAT DX,

Steve N5WBI
Houston TX


John H. Bryant <bjohnorcas@...>
 

Steve,

Gary is on vacation and I'm taking the "general ultralight questions" while he is gone.  In reference to your question about the Toshiba RP-F11, the general concept of Ultralight DXing is to limit ourselves to "entertainment grade" pocket portables to emphasize DX challenge and DXer knowledge/skill rather than the equipment. The Definitions Committee needed to find a way to separate "enthusiast radios" from "entertainment grade".... Obviously some of the mega-buck ICOM hand-helds, the smallest of which meet our size requirements, are enthusiast radios. Its the gray area in the middle that they found difficult to decide.  Finally, looking at the SRF-59 as the ancestor receiver for this hobby, but accepting digital dials as now being the norm in entertainment grade gear, too, they decided that the capabilities that denote non-compliant "enthusiast grade" in hand-held portables is SSB capability (a huge advantage in TA and TP reception) and double conversion. So the nifty G6 from Grundig is eliminated (SSB), as is the RP-F11 that you mentioned (double conversion.)

Honestly, there are those of us not on the Committee (like me) who think that the E100 with digital dial and 1 kHz. resolution (the latter a real boon in TA/TP work) is already over the line into enthusiast radios, despite being single conversion and no SSB.... However, that decision was made long ago and won't be rescinded... and I might point out, I own a whole double handful of E100s... and love them!

There will always be the desire on most of our parts (including mine) for a better receiver, but still within the bounds of Ultralighting... I hope that we all keep looking. 

Steve, you might also consider getting into the Unlimited Class of modified Ultralights... there actually are limits to the modifications allowed (See Definitions in the Ultralight File @ DXer.ca), but its the way that I relieve the frustration of limited equipment.... and messing with these things is reactively lo-tech, inexpensive and loads of fun.

Thanks for asking!

 

John B.
Orcas Island, WA, USA
Rcvrs: WiNRADiO 313e, Eton e1, Ultralights
Antennas: Two 70' x 100' Conti Super Loops, West and Northwest



At 04:55 PM 7/30/2008 +0000, you wrote:

Gary,

Thanks for the great info!

The 570/1480 image problem, to the best of my knowledge, is the only
such problem I've encountered with my radios here in Houston. Looking
at KLVL-1480's antenna patterns, I see that I'm directly in their
"gun-sights" for both day and night. That may explain a lot of why
they're such a pest.

Otherwise, the E-100 has turned out to be a great little radio. I still
haven't had a lot of time to give it a full test, though. Maybe this
weekend (?).

Do you know of any ultralights that employ dual conversion on
mediumwave?

Also, I have a Toshiba RP-F11 that measures 5.1 x 3.1 x 1.1 inches
(17.391 cu. in.). Would it be considered an ultralight? A good
picture can be found at:

http://www.universal-radio.com/used/UP86lrg.jpg

73 & GREAT DX,

Steve N5WBI
Houston TX


Steve Ponder N5WBI <n5wbi@...>
 

John,

Thanks for the clarification. I had printed out the definitions page
for personal reference. I saw the reference to "selectable IF filters"
but did not see any references to dual conversion (unless that means
the same thing).

I continue to be amazed by these UL radios. What used to take an
entire tabletop can now be put into your shirt pocket. Wow!

Again, thanks to you and to Gary who responded to my query about
the RP-F11.

Has anybody come forward with reviews of any of the radios listed on
the "Potential UltraLight Contenders" page? I have 5 of them - the
Kaito
WRX911, the Tecsun R9702, the Degen DE312, the Tecsun DR-910, and
the Grundig 300. Not that I have tons of time to devote to writing the
reviews, but maybe I could do at least one or two of the group's "Most
Wanted" if you could let me know what they are ...

73,

Steve N5WBI
Houston TX


satya@...
 

Hi Steve:

If you have the time and interest, a review of any one of those 5 would be
great!

Perhaps 10-15 minutes might show if any of these little guys have the
right stuff. Give 'em all a quick sensitivity check on a weak semi-local
during the day, one at the top and one at the bottom of the dial, compared
to the E-100 - that should quickly let you know which ones are worth
pursuing further. Then a quick selectivity check up against one your
favorite sloppers at night.

If any of them pass these two categories, we may have a new contender!!! I
can see the confused retailers now...

73 - Kevin S
Bainbridge Island, WA

Has anybody come forward with reviews of any of the radios listed on
the "Potential UltraLight Contenders" page? I have 5 of them - the
Kaito
WRX911, the Tecsun R9702, the Degen DE312, the Tecsun DR-910, and
the Grundig 300. Not that I have tons of time to devote to writing the
reviews, but maybe I could do at least one or two of the group's "Most
Wanted" if you could let me know what they are ...

73,

Steve N5WBI
Houston TX