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Sunday 23 July 2017

RTL-SDR reinstall on the shack computer

So it turned out I had to reinstall RTL-SDR related stuff on the shack computer, this was not as easy as I thought, the new stick shows up slightly differently in Zadig than on my laptop, I suspect this is because the version of Zadig on my laptop is actually older than the one on the shack computer, but it did in the end still work.

I started by trying a NooElec suggested SDR program, CubicSDR, this only detected my sound cards and thus did not work, even when I did some test transmissions on PMR446 channel 1, so I switched to HDSDR, however the waterfall displays in that program left me with a headache, so I looked for SDR#, which is now an Airspy product, and this worked after I downloaded and reinstalled RTL-SDR drivers, and Airspy have made some improvements to SDR#, including identifying bands and using the correct mode and frequency for them, or at least I think so, without an antenna connected at all I scanned through everything, it suggested military aviation is NFM, which makes no sense to me as civil aviation is AM, it also identified CB at 26.965-27.405MHz, again in NFM however AM and SSB are also legal to use in that band (the UK portion was not labelled, 10-metres was, and default set to SSB).

This worked well up to a point as during the second tune cycle (with a rubber duck antenna on the stick) the computer presented me with a BSOD, only the second time that machine has thrown one and only the second one on Windows 10 that I have seen, I let the computer reboot and I have not tried again yet.

The antenna I attached was not one of the supplied antennas but instead the Nagoya NA-771 antenna, using an SMA to BNC adaptor which I have to hand, the reception wasn't brilliant without turning the RX gain up, the tests I did for receive were performed in the FM broadcast band and PMR446 (though this was identified as 70cm as 446MHz is part of that allocation in the US and Canada), and it seems to work well.

I will get a video on YouTube in the next few days, and afterwards try and find an environment where there would be lots of radio activity (not counting pagers as they seem to be everywhere) for a proper field test of this stick

73 de 2E0EIJ

Tuesday 18 July 2017

Salvaging my original RTL-SDR stick.

My previous post mentioned my original RTL-SDR stick (original in the sense that I have a new improved one from NooElec on the way), I salvaged it and the internal USB wiring from the tin of oil it has sat in for some months, and degreased it, it is currently out of its casing with the casing and all the cables drying off.

I did this as I intend to show it on the YouTube video of the new one when it arrives and the fact the can is leaking oil as the sealing I did to it did not work as intended, also I plan to take it along to the amateur radio club.

I first want to test the stick with my tablet on the USB-OTG, I know the OTG will work for flash drives but will it run the RTL-SDR without complaining? one way to find out is to plug the stick into the OTG connector and then onto the tablet, if successful I will see if the new stick will also work so I can do some field tests for YouTube in an RF busy environment without having to lug a computer around with me.

Before any of that can take place of course, the stick needs to be tested on a normal computer to ensure it is actually working, this will be done using the modified USB cable that I use for the stick (also degreased), and a Windows machine, possibly my laptop, and SDR# if it is still on the laptop which it appears to be.

The tests will cause the stick to pick up some noise, an antenna may be fitted for testing purposes but this depends on many factors, the coax for the antenna was also degreased along with the BNC connector and should in theory still work, the MCX connector at the other end was also subject to this, though I probably won't need to use this much once the improved NooElec unit with an SMA connector arrives in the next couple of days, time to see what happens next.

73 de 2E0EIJ

Monday 17 July 2017

RTL-SDR revisited

As you are no doubt aware, I own one of the RTL-SDR sticks that do the rounds on the likes of eBay and Amazon, a cheap DVB-T stick that can be used as a software defined radio, trouble is it has flaws, those being that it can drift off frequency as it heats up and that it is prone to pick up of interference, particularly WFM from Band II, the FM broadcasting band, and methods of alleviating these problems do exists, my current stick is submerged in cooking oil in a golden syrup tin (though the sealant on all the connectors and the rest of the tin has been eaten away by the oil and it has escaped, so it is wrapped in a plastic bag), this did work well to keep the heat down and the noise contained, as some of it was conducted along the USB cable it was modified for the feed inside the can.

Though that stick is still very much usable, once salvaged from the tin and degreased, I have purchased an improved one by American company NooElec. they have taken the basic design and improved on it, replacing components, and removing redundant components, even going as far as to replace the MCX antenna port with an SMA (which I have a couple of adaptors for to allow use of any external antenna I see fit), the unit I have ordered is in a much different case than the original one I bought, and comes with a selection of antennas for different jobs, and as it is the same chips for USB and tuning as my existing stick it should work in a sense with the software that works with the old one with little change.

I partly bought this to use as a reliable scanner receiver, as I knew my existing RTL-SDR was not cut out for the job, and I hope to have it by the end of this week and will be doing a couple of YouTube videos on the stick all being well.

I'll see what happens with this

73 de 2E0EIJ

Sunday 16 July 2017

Shack re-establishment

With the QTH move all done, I have started to get my shack set up, the shack computer is operational but requires network connectivity and at present the only network feed to that room is for my web server, so I am looking at getting a switch in order to run the shack computer, the NAS box and the server off wired ethernet, I don't intend to set up wireless at all for the NAS and the shack computer will only be on wireless temporarily until an Ethernet switch arrives which will probably be around pay day.

The radios are working, I put the 2/70 antenna on top of an old computer case first on the top of my shelves, which I had assembled previously, SWR was very high but not dangerous to the radio, so I had a theory it may work on the radiator, so I attached the magnet there and low and behold the SWR dropped considerably, in fact the needle is not moving on 10 watts on 2 metres and is at most 1.4:1 on 70cm, which I find incredibly impressive for a compromise antenna, then came the turn of my CB antenna, I placed it on top of 2 old computer cases (one of these being one I used for the 2/70 antenna before placing it on the radiator), the mismatch on 11-metres was bad, at the bottom end was well into the red on the SWR metre but an improvement on the old excalibur, the top end (UK40 channel 40) was about 2, suggesting the antenna was far too short, theory, use it for 10-metres, plug it into 10-metre rig with a power output of around 10 watts, in the FM segment the SWR was very low, suggesting it will tune across 10-metres, which I will give a go at a low power at a later date.

I am so far impressed but as time progresses I intend to hide a couple of wire antennas in the nearby trees if possible to get me on both 10 and 11 metres at home, I already have my T2LT which has seen some but not a lot of action, and some kind of wire antenna for 10-metres could also be made, worth investigating

73 de 2E0EIJ

Saturday 15 July 2017

Disturbing news for the Amateur radio community

I have learned today that Chance Callahan KD0MXN is to study for the US General licence (he has technician already, which is like our foundation, General is like our Intermediate), this confirms that the FCC have been incompetent and disregarded all evidence I gave against him, and thus this individual is still in our community and has not yet been shunned out.

I suspect I know two reasons as to why he intends to do this, first and foremost is because he is now aware that I have my Intermediate and he feels that I should not be better than him in all things Amateur radio given his extreme pathological hatred of me, second is because his current callsign has been pretty much outed as bad.

So what can be done? Seeing as the FCC will not revoke his licence despite all the evidence I handed to them there is nothing that can be done, and with me moving QTH I have not been able to study for my Advanced yet, but I certainly intend to at some stage, something I have made very clear.

Despite a monumental pile of evidence against him and even his local Sheriff's department watching him due to other crimes why is he still licenced and allowed in our community? I guess we will never know, he will be ousted, and that is certain, as the Amateur radio community has no time for people like him.

73 de 2E0EIJ

Thursday 6 July 2017

second postponement of 2m FM activity contest

In light of my car being serviced on Tuesday I arrived back home too late to get the rig set up in the car, I have decided to hold off again of the 2m FMAC until August, when I will be able to take part with no hindrance as my move will be complete and my car is not due back in the garage until MOT day (which will be done at the back end of August to allow travel to the National Hamfest the following month).

I still need to set up the rig in the car as I can't put the antenna onto the roof of the car while it is wet as it has been raining heavily lately and my car is full of all sorts of things including my bicycle which has been removed from my shed while work goes on.

I have not had a lot of time on air with the move either and my shack is still not set up, as I have some finishing works at the old QTH before I hand the keys back to the local housing department, I still have all my HTs at the new QTH but I don't have the chargers plugged in as these normally go in the shack.

I should be operating again in the next few days all being well.

73 de 2E0EIJ