Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dd01.r1000.mx.aol.com (Internet Inbound) with ESMTP id 7CE5A38000086; Sun, 7 Apr 2013 12:30:43 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1UOs3i-0003rx-Nd for rs_out_1@blacksheep.org; Sun, 07 Apr 2013 17:03:10 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1UOs3h-0003ro-MR for rsgb_lf_group@blacksheep.org; Sun, 07 Apr 2013 17:03:09 +0100 Received: from smtpout1.wanadoo.co.uk ([80.12.242.29] helo=smtpout.wanadoo.co.uk) by relay1.thorcom.net with esmtp (Exim 4.77) (envelope-from ) id 1UOs3d-0004re-Hu for rsgb_lf_group@blacksheep.org; Sun, 07 Apr 2013 17:03:08 +0100 Received: from AGB ([2.26.13.195]) by mwinf5d14 with ME id M42j1l00M4CW4NS0342jgh; Sun, 07 Apr 2013 18:02:44 +0200 Message-ID: <6FEE03C67D0F46F2AB4A0BBE2B1C0183@AGB> From: "Graham" To: References: <122E7FDB629A419F812E13FCF3EAF6BD@AGB> <1B78A630D31B4549BDCC602762707068@AGB> <993A77CEFEDD48F2823CA7CBA5C07785@PcMinto> <9959A022143F43F7967F546EF3FDAEE6@PcMinto> <7C6AA48210FA40A59CDB4674946C9494@AGB> <1365346650.26115.YahooMailNeo@web133205.mail.ir2.yahoo.com> In-Reply-To: <1365346650.26115.YahooMailNeo@web133205.mail.ir2.yahoo.com> Date: Sun, 7 Apr 2013 17:02:43 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8117.416 X-MIMEOLE: Produced By Microsoft MimeOLE V14.0.8117.416 X-Spam-Score: 0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: R Pete Its was the background info on the ebay site , that I had spotted , the r820t running to 1.7 GHz ? that has to worth a look ? [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [80.12.242.29 listed in list.dnswl.org] 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 T_REMOTE_IMAGE Message contains an external image X-Scan-Signature: 4bc1d88be176c62a4e9044fd2912d945 Subject: =?UTF-8?Q?Re:_LF:_Re:_LF:_Re:_=C2=A310_Dongel-S?= =?UTF-8?Q?DR__Direct_sample_on_504_KHz_-_S?= =?UTF-8?Q?/N__TEST_?= Content-Type: multipart/alternative; boundary="----=_NextPart_000_00BC_01CE33B1.B84C01E0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.8 required=5.0 tests=HTML_40_50,HTML_FONTCOLOR_BLUE, HTML_MESSAGE,HTML_TAG_EXISTS_TBODY,MISSING_OUTLOOK_NAME autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false x-aol-global-disposition: G x-aol-sid: 3039ac1d408d51619f335b1d X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. ------=_NextPart_000_00BC_01CE33B1.B84C01E0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable R Pete=20 Its was the background info on the ebay site , that I had spotted = , the r820t running to 1.7 GHz ?=20 that has to worth a look ? 73 -G. From: M0FMT=20 Sent: Sunday, April 07, 2013 3:57 PM To: rsgb_lf_group@blacksheep.org=20 Subject: LF: Re: LF: Re: =C2=A310 Dongel-SDR Direct sample on 504 KHz - = S/N TEST=20 Hi Graham Cozy Cave still cheaper?????? that's with all the UK Tax (support = UK!!!) =20 Newsky TV28T RTL 2832U / R820T DVB-T DAB FM SDR stick only Your shopping basket contains 1 product Product Description Ref. Avail. Unit price Qty Total=20 Total products (incl. tax): =C2=A37.95=20 Total shipping (incl. tax): =C2=A31.98=20 Total (excl. tax): =C2=A39.93=20 Total tax: =C2=A30.00=20 Total (incl. tax) =C2=A39.93=20 https://www.cosycave.co.uk/product.php?id_product=3D288 73 es GL Pete M0FMT IO91UX From: Graham To: rsgb_lf_group@blacksheep.org=20 Sent: Sunday, 7 April 2013, 15:08 Subject: Re: LF: Re: =C2=A310 Dongel-SDR Direct sample on 504 KHz - = S/N TEST=20 Looking at ebay , one seller has the RTL2832U & R820T dongle = and indicates 25 to 1700 MHz range , using the r820t in place = of the e4000 front end ..... Item number: 160896097557 This is 'handy as the original chip set items are becoming = difficult to source and over priced ! =20 Defiantly the green light to hack the original for MF/HF and = buy the new for vhf/shf=20 73's Graham=20 From: Minto Witteveen=20 Sent: Sunday, April 07, 2013 9:33 AM To: rsgb_lf_group@blacksheep.org=20 Subject: LF: Re: =C2=A310 Dongel-SDR Direct sample on 504 KHz - S/N = TEST=20 Hi Graham, Yes I have the slider set to (nearly) maximum on 2 and 70 J With a direct compare (same antenna, same signal) the dongle is = definitely less sensitive than my 897, I suspect (but have not = scientifically determined) at least several s-points. I only tested NFM. = Other dongle owners here report the same so it is not an issue with my = copy of the dongle=E2=80=A6 73=E2=80=99s Minto pa3bca = -------------------------------------------------------------------------= - Ceterum censeo Carthaginem delendam esse From: Graham=20 Sent: Sunday, April 07, 2013 02:00 To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: Re: =C2=A310 Dongel-SDR Direct sample on 504 KHz - = S/N TEST=20 Ok...Minto,=20 - silly question , you have the gain slider set max in the = driver set-up panel ? Then agen , my ft897 could be u/s ! =20 I will shorten the min coax I have soldered to the device , and = see what happens on VHF with the gen on Sunday=20 with the same levels , ive emailed you a recording of ssb = station on 4 meters , using the dongle and indoor Ae=20 73 -G,.=20 From: Minto Witteveen=20 Sent: Saturday, April 06, 2013 11:16 PM To: rsgb_lf_group@blacksheep.org=20 Subject: LF: Re: =C2=A310 Dongel-SDR Direct sample on 504 KHz - S/N = TEST=20 Hi Graham, So maybe I should order another (type) of RTL2832 dongle. The one I = have certainly is wayyy less sensitive than my ft897 on 2 and 70. = Probably the type of tuner is different. Well for the direct sampling test it is irrelevant. I will have to = filter 472, but that is no problem as I already have such a filter = (ft817 will overload from AM@675 without the filter). I also have a 1.8 MHz higpass. And as you say, at EUR 10 for a dongle = there is not much to complain about. It is fascinating that it works so = well as it does. 73=E2=80=99s Minto pa3bca = -------------------------------------------------------------------------= - Ceterum censeo Carthaginem delendam esse From: Graham=20 Sent: Saturday, April 06, 2013 23:58 To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: Re: =C2=A310 Dongel-SDR Direct sample on 504 KHz - = S/N TEST=20 Ok Minto=20 Yes this is the Q not Q or what ever connection to the A/d =20 http://mikikg.files.wordpress.com/2012/08/rtl2832u-dc-mods.pdf As to improvement's , ive no idea ! , but you note the coupling = C are both removed , the gain from the mini-whip my well be = enough to 'tip the balance' but s/n for data is more important = than 'peak signal level' so gain (lots) may not be the holy = grail , I did copy nav text at 100% from the south of Uk , audio = level was very low , but at a good s/n. =20 [ Gary's point , yes could switch , but I have the impression , = more could be gained by using the balanced feed as in the = link above , you can run 2 dongles in the same pc as the usb = location seems to be part of the driver addressing=20 There is 'no' gain in the A/D , to day , the racal ra6790 = produced a S3 / 4 cw copy from 0.1 uV , as can be seen from the = s-lab shot , but a low noise pre-amp would solve the problem and = with no additional mixer , IMD should be much reduced , night = time HF was quite reasonable , left it on 14,103 with the 40ft = vertical, returned after dinner and had missed Iceland with -8dB = signal .. typical ! =20 The mixer in the dongle cannot have much dynamic range , = compared to one designed for 'HF , eg the ra1769 first mixer = is fed with 5 to 7 watts of RF to ensure minimal transit times = and over 120 dB dynamic range , this could be a contributing = factor to any 'strange patterns , which must be aggravated by = having two mixers in the rf path - one may be 'good' but the = e4000 may not be , where as the a/d seems to be quite clean=20 You have the same item I have hacked for MF , showing in the = driver list as generic , the other is the original ezeycap as per = the first posts ... When you say the vhf/uhf is 'low' that's = odd as I would say this one (ezy) is as good as the ft897d on = 2/70 and on 4 meters , its better than the spectrum trans V , = using HDSDR =20 But the main thing is , it put's a reasonable set-up in a = very affordable price , will be interesting to see the = performance ,D/S linked to the mini-whip , may be the only way = round the large carrier problem will be filtering , or a move = to a better a/d , at least any pre-amps and filters are = transferable , should a better A/D be used at a future data ? 73 -G.=20 From: Minto Witteveen=20 Sent: Saturday, April 06, 2013 10:15 PM To: rsgb_lf_group@blacksheep.org=20 Subject: LF: Re: =C2=A310 Dongel-SDR Direct sample on 504 KHz - S/N = TEST=20 I have been experimenting too with an RTL-SDR dongle now for a few = weeks. I currently use a transverter to listen to lf/mf/hf. This = transverter upshifts the spectrum with 100 MHz. Although the RTL-DSR is rather deaf when used on 2m or 70 cm (compared = to my ham equipment) when used for HF it is sensitive enough with a = pa0rdt active antenna. I can also use it on 472. But there I have to use my 472 KHz narrow = band filter to keep out mf, especially Radio Mario @ 675 Khz. And = although the dynamic range is not stellar, as far as I can determine = reception on 472 is very comparable to my ft817.. Grahams pointer to the direct sampling option got me interested. Time = to let the nice people from dealextreme send me another on for EUR 10 so = I can =E2=80=98experiment=E2=80=99 with it. Some interesting websites/video=E2=80=99s about the direct sampling = implementation: = http://ttrftech.tumblr.com/post/36283680013/rtl2832u-dongle-mods-for-7mhz= -reception-with-gqrx and = http://mikikg.wordpress.com/2012/08/22/prepravka-dvb-t-usb-prijemnika-sa-= rtl2832u-za-hf-0-28mhz/ First site is in Japanese, second in Croatian, but Google (translate) = is your friend. It is very nice to get an instant overview of 2 MHz of spectrum. I = have been plagued by ever increasing QRM here, which forced me to place = a magnetic loop antenna in my backyard to get any reception at all. QRM = now is S9+10 dB form 100 KHz to nearly 50 MHz. I have not been able to = find out what causes this (not generated in my house). See attached = screenshot for a part of the spectrum around 80 meters. This wavy = pattern can be seen everywhere from nearly DC to 50 MHz, with some clean = area=E2=80=99s in between. Sometimes the QRM stops waving =E2=80=93 = straight lines for several seconds and then the waving restarts. I am very jealous of other hams showing waterfall patters where = everything between real signals is dark blue... :-( Anybody ANY idea what might cause this kind of QRM?=20 73=E2=80=99s Minto pa3bca = -------------------------------------------------------------------------= - Ceterum censeo Carthaginem delendam esse From: Gary - G4WGT=20 Sent: Saturday, April 06, 2013 19:55 To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: =C2=A310 Dongel-SDR Direct sample on 504 KHz - S/N = TEST=20 Graham, Maybe then....if the PCB was installed in a small aluminium box the = capacitor could be removed & a switch fitted to select the original = (VHF) arrangement or the HF/LF method. Possibly fit a pre-amp also. 73, Gary - G4WGT. ------=_NextPart_000_00BC_01CE33B1.B84C01E0 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
R Pete
 
Its was the  background  info  on the  = ebay  site=20 , that  I had spotted  , the  r820t   running = to =20 1.7 GHz ?
 
that has to  worth  a look ?
 
73 -G.
 

From: M0FMT
Sent: Sunday, April 07, 2013 3:57 PM
Subject: LF: Re: LF: Re: =C2=A310 Dongel-SDR Direct sample = on 504 KHz -=20 S/N TEST

Hi Graham
 
Cozy Cave still cheaper??????  that's with all the UK = Tax=20 (support UK!!!)
 
 
=20
Newsky TV28T RTL 2832U / R820T DVB-T DAB FM SDR stick=20 only
Your shopping basket contains 1=20 product
Product Description Ref. Avail. Unit price Qty Total
Total products (incl. tax): =C2=A37.95
Total shipping (incl. tax): =C2=A31.98
Total (excl. tax): =C2=A39.93
Total tax: =C2=A30.00
Total (incl. tax) =C2=A39.93
 
https://= www.cosycave.co.uk/product.php?id_product=3D288

73 es GL Pete M0FMT IO91UX
From: Graham=20 <g8fzk@g8fzk.fsnet.co.uk>
To: = rsgb_lf_group@blacksheep.org=20
Sent: Sunday, 7 = April 2013,=20 15:08
Subject: Re: = LF: Re:=20 =C2=A310 Dongel-SDR Direct sample on 504 KHz - S/N TEST =

Looking  at  ebay  , one  seller  = has =20 the    RTL2832U & R820T  = dongle  and  indicates   25  to 1700 MHz = range =20 , using  the  r820t   in place of the =20 e4000   front  end  ..... = Item number:=20 160896097557

This  is  'handy  as = the =20 original  chip set items  are becoming  difficult  = to  source  and  over  priced  ! 
 
Defiantly  the  green  = light=20 to   hack the  original  for  MF/HF and  = buy  the  new  for  vhf/shf
 
73's Graham
 

From: Minto Witteveen =
Sent: Sunday, April 07, 2013 9:33 AM
To: rsgb_lf_group@blacksheep.= org=20
Subject: LF: Re: =C2=A310 Dongel-SDR Direct sample on 504 = KHz - S/N=20 TEST

Hi Graham,
Yes I have the slider set to (nearly) = maximum on 2=20 and 70 J
With a direct compare (same antenna, same signal) the = dongle is=20 definitely less sensitive than my 897, I suspect (but have not = scientifically=20 determined) at least several s-points. I only tested NFM. Other dongle = owners=20 here report the same so it is not an issue with my copy of the=20 dongle=E2=80=A6
73=E2=80=99s Minto = pa3bca
 
-------------------------------------------------------------------= -------
Ceterum=20 censeo Carthaginem delendam esse
 
From: Graham
Sent: Sunday, April 07, 2013 02:00
To: rsgb_lf_group@blacksheep.= org=20
Subject: Re: LF: Re: =C2=A310 Dongel-SDR Direct sample on = 504 KHz - S/N=20 TEST
 
Ok...Minto,
 
- silly  question  , you  have  the  = gain slider=20 set  max in the  driver set-up panel ?  Then agen , = my =20 ft897  could  be  u/s  ! 
 
I will  shorten the  min coax  I  have  = soldered=20 to the  device  , and  see  what  = happens  on=20 VHF  with the  gen on Sunday
with the  same  levels  , ive  emailed =20 you  a  recording  of  ssb   = station  on=20 4  meters  , using  the  dongle  and =20 indoor  Ae
 
73 -G,.
 
 
 
 
 
From: Minto Witteveen =
Sent: Saturday, April 06, 2013 11:16 PM
To: rsgb_lf_group@blacksheep.= org=20
Subject: LF: Re: =C2=A310 Dongel-SDR Direct sample on 504 = KHz - S/N=20 TEST
 
Hi Graham,
So maybe I should order another (type) = of RTL2832=20 dongle. The one I have certainly is wayyy less sensitive than my ft897 = on 2=20 and 70. Probably the type of tuner is different.
Well for the = direct=20 sampling test it is irrelevant. I will have to filter 472, but that is = no=20 problem as I already have such a filter (ft817 will overload from AM@675 = without the=20 filter).
I also have a 1.8 MHz higpass.  And as you say, at = EUR 10 for=20 a dongle there is not much to complain about. It is fascinating that = it works=20 so well as it does.
73=E2=80=99s Minto = pa3bca
 
-------------------------------------------------------------------= -------
Ceterum=20 censeo Carthaginem delendam esse
 
From: Graham
Sent: Saturday, April 06, 2013 23:58
Subject: Re: LF: Re: =C2=A310 Dongel-SDR Direct sample on = 504 KHz - S/N=20 TEST
 
Ok  Minto
 
Yes this  is the  Q not Q or  what  = ever =20 connection  to the  A/d 
 
http://mikikg.files.wordpress.com/2012/08/rtl2832u-dc-mod= s.pdf
 
As to improvement's  , ive no idea  ! ,   but = you  note the   coupling   C  are =20 both  removed , the  gain from the  mini-whip  = my =20 well  be  enough to  'tip the  balance' =20 but   s/n  for  data  is  more =20 important  than  'peak signal level'   so  = gain=20 (lots)  may  not be the  holy  grail , I did  = copy  nav text  at 100% from the  south  of  = Uk ,=20 audio  level  was  very low , but  at a  good = s/n. 
 
[ Gary's  point , yes could  switch , but  I have=20 the  impression , more  could  be  gained  = by =20 using  the  balanced  feed  as  in the  = link=20 above , you  can  run  2  dongles  in  = the =20 same  pc  as  the  usb  location  = seems =20 to  be  part of the  driver  addressing
 
There  is  'no'  gain in the  A/D , to =20 day  , the   racal  ra6790  produced  = a  S3=20 / 4  cw  copy  from  0.1 uV  , as  can = be =20 seen from the  s-lab shot , but  a low noise  = pre-amp =20 would  solve the  problem and  with  = no  =20 additional  mixer  , IMD should  be   = much =20 reduced  , night time  HF was  quite  reasonable , = left  it  on   14,103  with the  = 40ft =20 vertical, returned  after  dinner  and   had=20 missed  Iceland  with  -8dB  signal .. typical=20 !  
 
The  mixer  in  the  dongle  = cannot =20 have  much  dynamic  range  , compared to = one =20 designed  for  'HF   , eg  the  = ra1769 =20 first  mixer  is fed  with   5  to 7 = watts =20 of  RF to  ensure minimal  transit  times  = and =20 over  120 dB  dynamic  range ,  this  = could =20 be  a contributing factor  to  any  'strange=20 patterns  , which  must  be  aggravated  = by =20 having  two  mixers  in the  rf  path  = - =20 one may  be  'good'  but  the  = e4000  =20 may  not  be , where  as  the  a/d  = seems =20 to  be  quite  clean
 
You have the  same  item I have  hacked  = for  MF=20 , showing  in the  driver  list as  generic , = the =20 other  is the  original ezeycap  as per the  = first =20 posts  ... When  you  say  the  vhf/uhf  = is  'low'  that's  odd  as  I would  = say =20 this  one  (ezy)  is  as  good  as = the =20 ft897d on 2/70  and on 4  meters  , its  = better  than=20 the  spectrum  trans V  , using  HDSDR  =
 
But  the  main thing  is , it  put's  a=20 reasonable   set-up   in a very  = affordable =20 price , will  be  interesting  to  see  = the =20 performance  ,D/S linked to the  mini-whip  ,  may = be=20 the  only  way  round the  large  = carrier =20 problem  will  be   filtering  , or  = a =20 move to  a better  a/d  , at  least  = any =20 pre-amps  and  filters  are  transferable  ,=20 should  a  better   A/D be  used  = at =20 a  future  data  ?
 
73 -G.
 
 
 
 
 
 
 
 
From: Minto Witteveen =
Sent: Saturday, April 06, 2013 10:15 PM
To: rsgb_lf_group@blacksheep.= org=20
Subject: LF: Re: =C2=A310 Dongel-SDR Direct sample on 504 = KHz - S/N=20 TEST
 
I have been experimenting too with an = RTL-SDR dongle=20 now for a few weeks. I currently use a transverter to listen to = lf/mf/hf. This=20 transverter upshifts the spectrum with 100 MHz.
Although the = RTL-DSR is=20 rather deaf when used on 2m or 70 cm (compared to my ham equipment) = when used=20 for HF it is sensitive enough with a pa0rdt active antenna.
I can = also use=20 it on 472. But there I have to use my 472 KHz narrow band filter to = keep out=20 mf, especially Radio Mario @ 675 Khz. And although the dynamic range = is not=20 stellar, as far as I can determine  reception on 472 = is very=20 comparable to my ft817..
Grahams pointer to the direct sampling = option got=20 me interested. Time to let the nice people from dealextreme send me = another on=20 for EUR 10 so I can =E2=80=98experiment=E2=80=99 with = it.
Some interesting websites/video=E2=80=99s about the = direct sampling=20 implementation:
http://ttrftech.tumblr.com/post/36283680013/rtl2832u-dongl= e-mods-for-7mhz-reception-with-gqrx
and
http://mikikg.wordpress.com/2012/08/22/prepravka-dvb-t-usb= -prijemnika-sa-rtl2832u-za-hf-0-28mhz/
First site is in Japanese, second in = Croatian, but=20 Google (translate) is your friend.
It is very nice to get an instant = overview of 2 MHz=20 of spectrum. I have been plagued by ever increasing QRM here, which = forced me=20 to place a magnetic loop antenna in my backyard to get any reception = at all.=20 QRM now is S9+10 dB form 100 KHz to nearly 50 MHz. I have not been = able to=20 find out what causes this (not generated in my house). See attached = screenshot=20 for a part of the spectrum around 80 meters. This  = wavy=20 pattern can be seen everywhere from nearly DC to 50 MHz, with some = clean=20 area=E2=80=99s in between. Sometimes the QRM stops waving =E2=80=93 = straight lines for several=20 seconds and then the waving restarts.
I am very jealous of other hams showing = waterfall=20 patters where everything between real signals is dark blue...=20 :-(
Anybody ANY idea what might cause this = kind of QRM?=20
73=E2=80=99s Minto = pa3bca
 
-------------------------------------------------------------------= -------
Ceterum=20 censeo Carthaginem delendam esse
 
Sent: Saturday, April 06, 2013 19:55
Subject: Re: LF: =C2=A310 Dongel-SDR Direct sample on 504 = KHz - S/N=20 TEST
 
Graham,
 
Maybe then....if the PCB was = installed in a small=20 aluminium box the capacitor could be removed & a switch fitted to = select=20 the original (VHF) arrangement or the HF/LF method. Possibly fit a = pre-amp=20 also.
 
73, Gary - G4WGT.
 
 


------=_NextPart_000_00BC_01CE33B1.B84C01E0--