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Loggings => MW Loggings => Topic started by: pinto vortando on March 02, 2019, 0323 UTC

Title: DXing with a Xtal set
Post by: pinto vortando on March 02, 2019, 0323 UTC
AM BCB conditions have been rather unsettled here in Michigan the past couple of evenings but
anyway got out my xtal set last evening around 2100 EST.
As expected, results were not too good... lots of QSB.  However, did manage to
positively ID several stations as they faded in and out:

WHAM-AM 1180  Rochester  NY
faded in just enough to get the ID, "Wham news radio 11-80"
then gone

KDKA-AM  1020  Pittsburg  PA
talking about the Pittsburg Home and Garden Show

WLW-AM  700  Cincinnati  OH
could hear it in and out under local powerhouse WJR 760
(remember this is a xtal set, selectivity isn't the greatest)

WBZ-AM  1030  Boston  MA
"Nightside" program with host Dan Rea
this station, unlike the others, had a solid signal in here all evening
Title: Re: DXing with a Xtal set
Post by: Davep on March 04, 2019, 1100 UTC
What's your circuit?

Ill try over a few nights.  This one I used a 386 chip op amp , the slight hum in the video is from wall wart ps which can be eliminated with a 9 volt battery but it rips through them.  You can get decent selectivity by adding a trap or tuning the antenna coil and it also allows a longer antenna without overloading.
. The sensitivity is limited by the diode , not all are the same.

https://m.youtube.com/watch?v=1K4KB55-QBw


Over a few nights clipped on to the hf wire

WPTY 1690  Lexinton Pk MD  Lionel Ritchie
WBCN 1660  Charlotte NC   sports discussion
?        1590
?        1570
WFME  1560  NY NY
WGH    1310   local
WTJZ    1270 Newport News Va
WWVA  1170 Wheeling WVa
KYW     1060 Philadelphia    newsradio
WVXX   1050  Local  " La Selectra" " los top 20"
WBZ     1030  Boston
WINS    1010 NY NY
UNID    960    Political talk
WCBS   880    NY  NY
WTAR    850 local swamping adjacent
WNIS    790 local  swamping  adjecent
CFZM    740  Toronto   Rick Springfield Jessie's girl   good copy
WOR     710   New York   " WOR news time 905"
WGN    720     Chicago
WFAN   660    New York NY.  Sports  excellent copy
WSNR   620   Lyndhurst NJ
WCAO   600    Baltimore   gospel
RR        570 Santa Clara   time blips

CW on 160 meters even though the trap doesn't reach that high



Title: Re: DXing with a Xtal set
Post by: Josh on March 04, 2019, 2120 UTC
1n5711 and bat46 are tops for silicon diodes, try a 1n34a for "geranium" diodes, better than a 1n60.
Title: Re: DXing with a Xtal set
Post by: Davep on March 04, 2019, 2313 UTC
I bought a 10 pack of 1n34 and checked through. Some are noticeably louder than others.
Title: Re: DXing with a Xtal set
Post by: pinto vortando on March 05, 2019, 1903 UTC
What's your circuit?

Ill try over a few nights.  This one I used a 386 chip op amp , the slight hum in the video is from wall wart ps which can be eliminated with a 9 volt battery but it rips through them.  You can get decent selectivity by adding a trap or tuning the antenna coil and it also allows a longer antenna without overloading.
. The sensitivity is limited by the diode , not all are the same.

Circuit is just typical basic diode and with 250 uH coil and 365 uuf air variable condenser.
 
Not all diodes are created equal as you noticed.  Had some old (50+ yrs) germanium
type, probably 1N34,  here and picked the hottest of the bunch to use in the set.
Supposedly the old stock stuff is hotter than  new ones... idk ???
The  key is an antenna tuning unit inductively coupled to the tuning coil in the set.
The antenna coil is tuned by a couple of 365 uuf condensers in a switchable
series-parallel arrangement.  The trick is getting the proper spacing when coupling
the tuner to the set.  The closer the better for sensitivity but too close and selectivity
becomes bad to the point where stations are heard randomly all over the dial (no linear
"tracking" so to speak).

Have found that spider web wound coils seem to perform better than the usual
cylinder wound coils. 

btw, you may want to try running the op amp on 12 volts (say a couple of 6 volt
lantern batteries in series or a sealed 12 volt VRLA battery, the VRLA could be recharged if
you have the proper means to do so),  should run a looong time.  :) 
Title: Re: DXing with a Xtal set
Post by: Josh on March 05, 2019, 1950 UTC
A tunable loop should do well in enhancing selectivity.
Title: Re: DXing with a Xtal set
Post by: pinto vortando on March 05, 2019, 2007 UTC
A tunable loop should do well in enhancing selectivity.

Never tried that with a xtal set.
Has it worked for you and if so,
how did you couple it to the set?
Title: Re: DXing with a Xtal set
Post by: Davep on March 05, 2019, 2205 UTC
You can couple off a secondary "pick up " loop

8 ft loop radio with cool hand capacitance shields  https://m.youtube.com/watch?v=jxm2LQAO5ic.   


Title: Re: DXing with a Xtal set
Post by: Josh on March 06, 2019, 1858 UTC
A tunable loop should do well in enhancing selectivity.

Never tried that with a xtal set.
Has it worked for you and if so,
how did you couple it to the set?

I think the consensus is to feed the loop with the wire, and the loop resonates/sets selectivity for the antenna system overall, keep in mind a high q loop can cut the bw down to a few hundred hz.
Title: Re: DXing with a Xtal set
Post by: pinto vortando on March 06, 2019, 2047 UTC
You can couple off a secondary "pick up " loop

8 ft loop radio with cool hand capacitance shields  https://m.youtube.com/watch?v=jxm2LQAO5ic.

Cool  8) 
wonder if the XYL would let me put it in the living room.
Title: Re: DXing with a Xtal set
Post by: pinto vortando on March 06, 2019, 2104 UTC
Tried tuning around a bit just before sunrise.

Caught a sports station ID as 15-30,  probably WCKY Cincinnati.

The locals were mostly drowning out the DX as the sun came up but heard a faint signal...
thought the YL announcer said  WIP "Sports Radio Philadelphia"  but could not find a AM listing
for that call.  Did find a WIP FM 94.1,  anybody know the AM call and freq ?

Title: Re: DXing with a Xtal set
Post by: Boriken on March 06, 2019, 2344 UTC
WTEL 610kc. Used to be WIP when I lived in Delaware about 10 years ago.
Title: Re: DXing with a Xtal set
Post by: pinto vortando on March 07, 2019, 0047 UTC
WTEL 610kc. Used to be WIP when I lived in Delaware about 10 years ago.

OK, tnx.
Title: Re: DXing with a Xtal set
Post by: Davep on March 07, 2019, 1525 UTC
I did a drive by like in the loop video, it was not late enough for dx about 2300z .  You can see why AVC was invented !
https://m.youtube.com/watch?v=miAH2tIH3nI
Title: Re: DXing with a Xtal set
Post by: Josh on March 07, 2019, 2010 UTC
Oh what fun they had in the teens and twenties!
Title: Re: DXing with a Xtal set
Post by: pinto vortando on March 07, 2019, 2056 UTC
Oh what fun they had in the teens and twenties!

DX was a big deal. 
Title: Re: DXing with a Xtal set
Post by: pinto vortando on March 11, 2019, 2046 UTC
I did a drive by like in the loop video, it was not late enough for dx about 2300z .  You can see why AVC was invented !


What kind of antenna are you using ?
Title: Re: DXing with a Xtal set
Post by: Davep on March 11, 2019, 2321 UTC
The hf  antenna 
Title: Re: DXing with a Xtal set
Post by: Pigmeat on May 10, 2019, 1314 UTC
I built the Radio Netherlands one meter MW loop on a pvc frame and wooden base about 20 years ago. My wife didn't seem to mind but I wasn't allowed to take it outside or downstairs where the neighbors and the the in-laws might see it.

I never used it on anything but modern superhets I could feed with the coupling loop. There was an interesting thing with that loop, it was resonant on harmonics. You could nail the New Guinea and Indonesian stations with it on 90 meters. I even got Bangla Betar on 4880 kHz on 60 coming over the Pole a few times with that loop.

Then we got a cat who saw it as a toy. That was the end of the loop.
Title: Re: DXing with a Xtal set
Post by: East Troy Don on May 10, 2019, 2012 UTC
I built the Radio Netherlands one meter MW loop on a pvc frame and wooden base about 20 years ago. My wife didn't seem to mind but I wasn't allowed to take it outside or downstairs where the neighbors and the the in-laws might see it.

I never used it on anything but modern superhets I could feed with the coupling loop. There was an interesting thing with that loop, it was resonant on harmonics. You could nail the New Guinea and Indonesian stations with it on 90 meters. I even got Bangla Betar on 4880 kHz on 60 coming over the Pole a few times with that loop.

Then we got a cat who saw it as a toy. That was the end of the loop.

Was that also the end of the cat ?
Title: Re: DXing with a Xtal set
Post by: Josh on May 11, 2019, 1849 UTC
The cat is now a world renowned harpist.
Title: Re: DXing with a Xtal set
Post by: East Troy Don on May 16, 2019, 2135 UTC
.....Playing at the iconic Pearly Gates  Concert Hall.   SRO.   ;D