Re: LF: WSPR 15 tonite

[John Lutz <n9jl@rocketmail.com>]

Stefan,

 

Thanks for the quick reply and the encouragement regarding my choice of the IDC-136.  It is good to know others are using it with success.  It sounds like modifications to the receiver itself aren't really necessary.

 

I have to admit that I'm really surprised by the distances being achieved at 136 KHz.  I would have expected that a couple hundred miles would be the upper limit, and that even that far would be pretty infrequent.  After looking at the WSPRNet database, I can see that I was very mistaken about that.

 

I see lots of reception reports from you for G3XKR (940km), R7NT (2234 km), 4X1RF (2850 km), and many other distant stations.  I would never have thought this possible!   :-)

 

Regarding my antenna, I will initially use a 7.25 meter ground-mounted vertical.  Normally, I use it for 30-meter operation.  I am in the process of constructing a PA0RDT mini-whip.  I understand that "active" antennas of this type are fairly popular of LF/VLF work.

 

Again, thank you for taking time to respond to my email.  I hope to be WSPRNet active very soon.

 

73,

 

John / N9JL

 

On Saturday, October 19, 2013 7:24 PM, Stefan Schäfer <Stefan.Schaefer@iup.uni-heidelberg.de> wrote:

Hello John,

Good decision! LF is the real challenge and as you can see here, 160m is certainly not "Top Band" ;-)

The IDC-136 receiver is used with great results. It is used by YV7MAE, TF3HZ, Edgar J. Twining  (SWL, VK7) and many more stations. Stability is fine for WSPR-15. Got a decode by YV7MAE last season over 7800 km distance (https://dl.dropboxusercontent.com/u/19882028/LF/WSPR15_LF_15022013.png). And BTW the manufactorer of the RX is also member of this reflector :-)

I guess the sensitivity and dynamic range is completely sufficient for EN51VM. Proven useful modifications can be done on the RX antenna for most radio stations. A cleaner earth or a better decoupling to the noisy shack for example.
What kind of antenna do you inted to connect?

73 and good luck on LF!

Stefan/DK7FC


Am 19.10.2013 20:20, schrieb John Lutz:

Gents,

 

Please forgive me if this isn't the correct way or place to ask the following question, but I've pretty much exhausted all other possibilities...

 

After almost 40 years of HF DXing, I finally decided to try QRSS and WSPR reception on 137 KHz.  Knowing that my stock FT-920 isn't the best at frequency stability, I decided to find a dedicated rig - something simple, inexpensive, and yet stable enough to serve the intended purpose.  I chose the IDC-136II direct conversion "receiver" from ICAS Enetrprises in Tokyo.  I put the quote marks around the word receiver, because the unit is really just a down-converter, with the lower mixing product at audio frequencies.

 

I've read that people (VK2XV and others) have devised modifications for the IDC-136II, but I haven't been able to get any details.  I'm wondering if anyone here is using one of these units, and (if so) what their experience with it has been. I'm especially interested in chasing down details on any modifications that have proven useful for enhancing dynamic range or sensitivity.

 

Thanks very much.

 

John N9JL

EN51vm

On Tuesday, October 8, 2013 5:43 PM, Stefan Schäfer mailto:Stefan.Schaefer@iup.uni-heidelberg.de wrote:

LF,

tonite i'm back in WSPR-15 until 06:15 UTC.
Reports welcome.

73, Stefan/DK7FC