Hans discovers a JRC NRD-630 on eBay

Many thanks to SWLing Post contributor, Hans de Zeeuw (MM6HDZ), who writes:

Hi, Thomas here’s a message from bonny Scotland:

Yesterday I found at eBay a JRC NRD-630 receiver for auction. The receiver is located in London, UK and the seller ships worldwide:

Click here to view on eBay.

An opportunity for people who are looking for this very rare receiver.

This is just the sort of receiver Dan Robinson could have in his collection!  Looks like the NRD-630 might fetch a hefty price at auction, but I wonder if it’ll exceed the original price (which I’m sure was also hefty!)?

Thanks, Hans.

Any Post readers own the JRC NRD-630? Please comment!

Activating mobile phone FM: FCC Chairman Ajit Pai’s remarks at NAB symposium

Many thanks to SWLing Post contributor, Aaron Kuhn, who shares the following:

FCC Chairman Ajit Pai’s remarks at the North American Broadcasters Association’s Future of Radio and Audio Symposium from today have been posted at

http://transition.fcc.gov/Daily_Releases/Daily_Business/2017/db0216/DOC-343529A1.pdf

I found the most interesting info in the statement is only 44% of the top selling smartphones in the US have an FM Chip activated have them activated. This figure pales in comparison to Mexico, where 80% of the top selling smartphones have the FM Radio chip activated.

Chair Pai goes on to state:

“You could make a case for activating chips on public safety grounds alone. The former head of our Federal Emergency Management Administration has spoken out in support of this proposal.

[…]I’ll keep speaking out about the benefits of activating FM chips. Having said that, as a believer in free markets and the rule of law, I cannot support a government mandate requiring activation of these chips. I don’t believe the FCC has the power to issue a mandate like that, and more generally I believe it’s best to sort this issue out in the marketplace. For despite the low numbers, we are seeing progress; in the last two years, the percentage of top-selling smartphones in the United States that have activated FM chips has risen from less than 25% to 44%. “

Which leads me to this question for the SWLing Post community: would the benefits, emergency and otherwise, of mandated, activated FM Receiver Chips in new Smartphones sold outweigh the free market arguments?

Feel free to share your comments!

Please note: our SWLing Post comment moderators keep this site a safe haven from partisan politics–after all, we’re here to talk and play radio! Sometimes, however, local/international politics and radio intersect, but please leave partisan discussions or any animosity for specific politicians for a political site. 🙂

RTÉ longwave set to continue “until at least 2019”

(Source: The Irish Post)

RTÉ are set to continue transmitting their longwave 252 service until at least 2019 after positive talks took place at a consultative meeting in London.

The news follows a statement issued by RTÉ back in October in which the state broadcaster announced its “intention to close the service in 2017.”

RTÉ said at the time that they were exploring the possibility of using ‘alternative technologies’ to help maintain links with its audiences in Britain beyond the service’s closure.

But longwave is now set to continue transmitting through 2017 and 2018 after a week which saw calls for the service’s retention heard in the Seanad.

Last week, independent Senator Billy Lawless sought government assurances that the Irish in Britain would not lose access to longwave 252.

Senator Lawless urged Minister of State for the Diaspora Joe McHugh to “implore RTÉ management to reconsider this ageist and discriminatory cut” to its longwave 252 service.[…]

Read the full article via The Irish Post. 

FM Notch Filter for SDRPlay RSP1

RF filters are used (as the name implies) to filter/remove the frequencies you are not interested in and/or let frequencies you want pass . They come in lots of types. For example a band-pass filter lets the signals in a frequency range to pass through it and rejects/attenuates other frequencies. The opposite of band-pass filter is a band-reject or band-stop filter (also called a notch filter) which rejects/attenuates signals in a specific range and lets other frequencies get through the filter. Lots of different filters are used in SDRs and traditional radios. For example AM low-pass filters (only let frequencies lower than 1.7MHZ or so pass) or band-pass filters for various ham radio bands.

One of the popular use cases for a notch filter is in the FM broadcast range (88-108 MHZ in most parts of the world)

When you live near a powerful transmitter, it can affect the operation of your receiver in other near frequencies (or overload your receiver’s front-end), but I didn’t want the notch filter for this reason. I’ve got a SDRPlay RSP1 (among many other SDRs) which due to its architecture, has some images of FM band in the UHF range (for example in 330-350 MHZ). In fact they’re the images of the product of LO harmonics and FM frequencies.

You can temporarily move/shift the frequency by changing the LO frequency which does not remove them, but moves them around.

Another method to remove these images is using a band-stop filter.

This is the filter I’m using (Thanks to my friend Amirhosein Hasanpur who designed and built it):

Here you can see the effect of using a FM notch filter on my SDRPlay RSP1:

FM, without filter:

FM, with filter:

UHF (images) without filter:

UHF (images) with filter:

Here’s a link to a Zip file containing the PCB (in Protel), schematics (pdf) and S Parameters (pdf):

https://www.dropbox.com/s/l98kylrofohgqxf/SWLing.zip?dl=0

Note: Like any other SDR test/review, the results depend on lots of different parameters (various gain values, LNA, antenna, software, etc). These pictures are captured with the same conditions just to show the effectiveness of this filter and your milage will definitely vary, but expect a similar outcome. If you live close to a powerful transmitter or use LNAs, you will receive some signals, even when using the filter.

Final note: this issue is solved in the newer version of SDRPlay (RSP2) : it has software-selectable notch filters for FM and MW broadcast frequencies.

Mehdi Asgari, the author of this post, is a regular contributor to the SWLing Post. Mehdi lives in Tehran and is an active member of the EP2C amateur radio club.

Xenophon introduces bill which would force ABC to bring back shortwave broadcasts

(Source: Shepparton News)

The shortwave broadcast station which beamed Radio Australia to the Pacific from Shepparton could be coming back online.

Senator Nick Xenophon (Source: Twitter)

South Australian senator Nick Xenophon earlier this week introduced a bill to parliament, which if passed would force the ABC to bring back shortwave broadcasts.

[…]Senator Xenophon criticised the decision, which was made by ABC management and not the Federal Government, labelling it shortsighted.

‘‘The response to the shortwave cut-off demonstrates the woeful inadequacy of the ABC’s consultation process,’’ Senator Xenophon said.

‘‘Not only have we heard from many rural Australians concerned about the decision, our near neighbours such as Vanuatu and Papua New Guinea have also voiced serious concerns.’’

[…]‘‘The cost-cutting decision will save $1.9million a year — a tiny fraction of the ABC’s $1billion-plus annual budget,’’ he said.[…]

Read the full story at the Shepparton News.