Need a working A.M. and shortwave antenna for RTR-SDR + Upconverter

[dragon48]

Since I paid for the hardware, I'm allowed to complain about it:

I have the basic RTL-SDR (Blog V3 R820T2 RTL2832U 1PPM TCXO HF Bias Tee SMA Software Defined Radio with Dipole Antenna Kit.) USB. I just purchased Ham It Up Plus. After I set it up and configured the frequency offset, I was surprised that I couldn't even get reception from strong, local A.M. stations, when using the stock dual telescoping antennas. I clipped on a known working wire antenna (see - Writing to praise the "Slinky antenna.") to one of the metal telescoping antennas and still got nothing. I then resorted to unscrewing one of the SMA connectors, inserting a paperclip into the hole and then clipping the paperclip to the wire antenna. I was then able to pick up a local A.M. station, as well as a strong domestic Shortwave (4840 Hz) station, however, the reception was bad with static. WTF!

The odd thing was that I was later unable to reproduce this - couldn't get any A.M. or shortwave reception, using the same trick. I was also later unable to get A.M. or shortwave reception with a very reliable Dax Station Stalker indoor amplified antenna. I just hear hissing on the frequencies.

With my radios, I pick up SW stations from thousands of miles a day all the time. Last week I got a signal from Myanmar, (formerly Burma) 8,405 miles away, but now with my SDR, I can't even pick up a station that is transmitting at 50,000 Watts, only around 14 miles from me! I can't believe this. Increasing the gain and re-enabling the default bandpass filter did nothing.

I'm not stringing a 200 foot wire out my window or resorting to any other similar drastic measures. I need a practical, normal solution to my problems. Any ideas? Also, why was I able to get some reception (albeit crappy) with the paperclip SMA hack once, but can't get any reception with the hack now?

I'm using the latest version of SDR Sharp. Any tweaks that can perform some magic?

Thanks.

 

[spongella]

I've got the same RTL-SDR and upconverter as you dragon. The telescoping antennas that are packaged with SDR dongles are useless for the shortwave bands so best thing is an longer antenna. I recently bought the W6LVP loop which worked pretty well indoors when I was testing it initially but worked even better when outdoors. If you're restricted to indoor antennas then experiment, such as a 30 foot or longer wire running around the walls of the room. General rule with antennas is longer and higher is better.

As to why you were getting excellent reception one day and nothing the other could be simply a bad antenna connection or poor propagation. Propagation conditions change daily, hourly and seasonally.

Also, on the SDR# menu adjust the RF gain slider to adjust signal strength (click on the gear wheel for that). If set too low you'll hear very little. You came to the right place for help, lots of folks here with experience and willing to share.

 

[slicerwizard]

Since I paid for the hardware, I'm allowed to complain about it:

Sounds like you're connecting a high impedance antenna to a low impedance (~50 ohm) input and then complaining about the result.

 

[ka3jjz]

Can't you simply jumper the antennas you are using on your current radios to the RTL? You will likely need a SO-239 to SMA Male, if memory serves (I think the RTL SDR uses a SMA female antenna input), or whatever you use to go to the radios....

If you find overloading to be an issue - and being near NYC, it's very possible - a passive preselector will do the job nicely. You will know this if you cut your RF Gain down to almost all the way and still hear broadcast stations where they don't belong. We have a couple listed in the last section of...

Improving HF Reception - The RadioReference Wiki

wiki.radioreference.com

Mike

 

[dragon48]

Can't you simply jumper the antennas you are using on your current radios to the RTL? You will likely need a SO-239 to SMA Male, if memory serves (I think the RTL SDR uses a SMA female antenna input), or whatever you use to go to the radios....

Appreciate the advice, but this doesn't work. My main radios can get SW (AM if I want also) by simply clipping a long indoor wire run to any part of a stock metal telescoping BNC antenna. I have SMA to BNC converters and the appropriate gender changers to get the same antenna on the SDR, but when I clip it on the wire, nothing happens at all. I know the antenna works, as I get WFM broadcast radio and NFM UHF stuff like police and ambulance, when using that antenna.

I know there are antenna challenges, but I suspect something else is wrong when I can't even pick up strong, local A.M. (< 15 miles away) stations with my SDR.

 

[spongella]

When using the rtl-sdr with the upconverter: 1) are you powering the upconverter with 5V? 2) Toggle switch on the upconverter in the IF output position? 3) On the SDR# menu have you checked the "shift" box and entered -125,000?

 

[dragon48]

When using the rtl-sdr with the upconverter: 1) are you powering the upconverter with 5V? 2) Toggle switch on the upconverter in the IF output position? 3) On the SDR# menu have you checked the "shift" box and entered -125,000?

I am powering it with a USB hub which I assume is providing 5V, The toggle is set to upconverter. The lights on the upconverter show that it is in the correct position and getting USB power. Low voltage is not indicated. I checked "shift" and entered-125,000,000, which is the correct setting.

Major Update:

My shift was wrong, which I wasn't able to get any upconverted reception, after getting some originally, but it is still not great. I've got a BNC antenna which is clipped to my indoor slinky long wire antenna. So far, I get the best sound by enabling the bandpass filter and turning on RTL AGC (0 gain - more makes the sound worse.) .

Please give a listen. I think local A.M. should sound much better than this. Does the quality give a clue as to what is causing the reception issues? Any other SDRsharp settings I should tweak?

Mark - Clyp

Listen to Mark | Clyp is the easiest way to record, upload and share audio.

clyp.it

Here is a waterfall and overall screenshot that corresponds to the linked audio:

Sorry to have been torturing people for a while, as the no reception posts were completely my fault. I had the shift number correct initially when I reported bad reception, but SDR Sharp had crashed at some point after that, and the setting was lost. I then put in a value with the wrong number of zeros.

Appreciate all the help and advice so far.

 

[spongella]

No worries, it's not torture. There's a learning curve with SDR dongles. Been doing this many years with many different SDR dongles.

I see you are in NY and your screen grab shows 1010 kHz which is all news station WINS (a former New Yorker here ).

Click on the gear wheel, what is your sampling rate? I use 1.024 MSPS. Also, try another station, e.g. WCBS 880, is that a problem also?

The linked audio sounds just like mine, but you are experiencing some buzzing in the background. This interference can come possibly from nearby sources e.g. fluorescent light, street light, power lines or household appliances. You might try orienting your antenna in different directions to see if you can null out the noise, or try turning off suspect appliances.

 

[dragon48]

I was samling at 2048. 1024 sounds the same. Higher sounds worse (more crackling) - maybe my Surface Pro tablet can't process the higher MBS in time. Lower also sounds worse.

I'm getting the same buzzing with other local stations as well as little bit on Shortwave. I shut off a few fluorescent lights, but that didn't help. Living in a city apartment, with all the possible sources of RF interference, I'm grateful to get any reception at all. Where I work, we are unable to get any A.M. reception at all. I've already ruled out some sources of interference (monitor, Surface Pro, Cable Modem and WIFI router). Not much else I can shut off, but I'll look around. Currently, the antenna is facing the best direction for reception, but am always playing around with orientations.

Now that I'm actually getting reception, I'll have to compare this with reception from my radios on the same frequencies and hooked up to the same antenna, to see what (if anything else) I need to tweak in SDR Sharp. Playing around with gain settings now.

 

[dragon48]

Been scanning the Shortwave bands since my last post. Getting much better reception than A.M. I can live with that. Not going to be listening to much AM with the SDR.

 

[spongella]

Glad to hear it dragon48. Note that SDR dongles were originally designed for TV reception in Europe and other parts of the world and not for what they've morphed into nowadays as general coverage radio receivers. Thanks to talented individuals with foresight and imagination who wrote software to enable dongles to become the most inexpensive broadband receivers, we now reap the benefits of software defined radio. For the price of a dongle and upconverter you get coverage from the AM broadcast band to the L band, that's a pretty big slice of spectrum. Well, keep in touch and enjoy.

 

[dragon48]

I was up until 4:00 A.M. this morning playing with it. The more I figure out SDR Sharp, the more I like the dongle and upconverter. Originally, I was also disappointed with the unit, because it wasn't picking up some VHF stuff that my radios were. Then, I found the "gain" setting, and it picked up the stuff well.