Thursday, 13 July 2017

Bit Of A Lift

Tropospheric ducting can be categorised into two types:
a)A bit of a lift
b)A massive lift
Yesterday was actually type B.
On the way home from work I was stuck waiting for a train an hour so had a play around with the Netmonitor app on my phone. I was in an area where there is, normally a 2G phone signal if you're lucky. This means that if there is any odd propagation at UHF, all sorts of different phone masts start being picked up, and being near the sea also helps.
Well after leaving Netmonitor on for a bit, it had picked up a few cells in the Stranraer area, which is over the horizon so pretty good, but the best was a GSM signal from Larne in Northern Ireland (around 160km), and a 4G signal from Donaghadee, almost as far away across the Irish Sea.

When I got home, there were some big signals on the 70cm band, with at least one of the two Isle Of Man repeaters on 430.825 being full scale. I had a go at using the DMR handheld indoors to access GB7BR at Bride, and managed to get in. Also got into GB7UL at Carrickfergus from the handheld indoors.

 This repeater on 430.825 is usually no S-points, but full scale here.

A handy 'beacon' on 427.850 - Dublin buses trunking data, active 24/7 and the first thing to come through when there is any propagation across the Irish Sea on UHF.

On 145MHz simplex I spoke to GI0BDX in Newtownabbey.

One signal which I'm still not sure about is an Echolink gateway on 439.100, which I can't find on any lists (unless it's in Germany, which seems unlikely). Could be in Ireland as that's where lots of other signals were coming from.
Today (Thursday) everything was back to normal, back at its usual signal strength.

Thursday, 6 July 2017

The Perfect Radio

Here's a list of features I'd been thinking of for the perfect radio - mostly for VHF/UHF use and it would also be used in scanner mode quite a lot so many are scanning related. It's just a list I made for myself on my phone so not too much detail.

Radio Features:

Save to SD card/PC in format which can be exported as a video showing s-meter, freq etc. Only record when squelch open.

App to play back recordings with audio.

Smart skip - channels which are too busy get locked out until a break in activity - e.g. if >30% of scan passes are active it gets locked out until drops to <20 br="">
Per-channel delay times - e.g. wait 60 seconds even if squelch closed on a calling frequency in case they call again.

S-meter squelch on per-channel basis

Reset of all lockouts

Lockouts can have an expiry time

Linked search bands (like UBC3500)

Lock out ranges of frequencies or modes (applies to memories in that range too).

Record stats on channel use - auto lock out channels which are never used.

Open squelch on ANY CTCSS tone.

Lock out all non-tone channels

Signal in dBm on display

Select a lockout mask from a list

Change settings by geographic location - new set of memories or lockout mask when leaving town.

Select radio profiles from a list.

DMR auto identifies cc, slot and tg.

Direct entry of talkgroup via keypad on DMR.

Import DMR contact list of any size from csv file.

Export of all radio activity to CSV file (time and location of any signal above a threshold or transmission).

Audio AGC receiving on FM and digital modes - can be applied to recordings.

Each channel member of a rule group, with tones, lockout, power, geo zones etc.

Zones - distance from a point, grid squares etc. Can be either allow or lockout.

Priority tx frequency - when radio is set to auto/scan mode, any ptt activity transmits on a fixed calling frequency (could be APRS/emergency). If PTT pressed for >2 seconds, receive goes to that frequency and scanning stops. If not, it carries on scanning or rx on other freq.

Built in usb audio and serial port.

CAT control even on handhelds (micro USB) and FM mobiles.

Access over telnet/SSH, or serial console with command line.

Web browser access on ethernet/wifi models.

Bluetooth earphone/mic support.

Music playback off sd card/aux in, through bluetooth or speaker. Mix music with receive audio, ducking with squelch. So rx audio can go through car speakers.

Soft sub band muting, when sub band rx broadcast FM etc.

Channels can be scan groups or search bands.

Tone/dmr only smart search saves any real channels and not interference. Can choose to save only correct tone/group or ANY tone/group on that freq.

Tone/dmr only scan can still pause silently on other found channels for 5 sec if busy and show MPT1327 trunking ID etc. Channels can be set to stop while busy but have speaker audio muted, either recording or not recording.

Lockout rule for channels by time and date.

Programmable sequences of vfo/scanning e.g.

Vfo 145.500

If no activity for 10 min or if squelch open 30 sec in 60 sec step on

Vfo 433.500

If no activity for 10 min step on else goto start

Scan all groups

Goto start.

Email alert on events (per channel etc.)

Override of tone squelch above signal threshold

Voice keyer uses mp3/wav files

Schedule playing file/morse ID/beep/dead carrier, with delay on busy channel.

Built in decoding of jt65/psk/cw/packet/wspr with upload of spots or saving to text file. Aprs gateway support (passcode etc.).

App for android with ptt button support to simulate radio over internet connection.

Parrot mode - records up to a time limit and transmits received audio. Can use audio agc. Minimum tx time can be set or a preset audio file can be played instead of received audio if squelch was open for less than minimum time (broken signal or testing access).

Programmble i/o (3-16v in, 5v , source, sink or dry relay contacts out?) For events, ptt, squelch out etc. External squelch contacts can be different to audio squelch.

Digital vox on any signal above digital silence.

Momentary ptt latch/unlatching signal

Tx deviation independent of rx bandwidth

If signal above threshold, squelch changes to s-meter.

Direct link between 2 radios over network - controls on one radio take over from the one with the antenna, with full tx/rx audio.

Analogue i/o programmable, 0-10v in, 0-5v out for external s-meter, power control. Events can set or be triggered by voltage levels.

SWR available on analogue output or to set digital i/o.

Parameters of other radios can be read/written over network/internet. E.g your frequency can be sent to server/friend if within certain bands so they can see if anybody is on a certain band. Events can be sent, ptt pressed, squelch open etc.

Rewind last 20 seconds of audio - when squelch was open.

Events can be triggered by a certain frequency being active or above a threshold - "i can hear 440.800 so change to midlands profile" or "if paging >-30dbm, lock out range 108 - 200 MHz", checking on a 'silent' scanning memory.

Replace audio with a few seconds 'ringtone' or silence on selected channels when squelch opens, or if squelch opens and no tone/encrypted/no audio.

Squelch open/close 'roger' beep can vary depending on signal level.

Receive diversity on 2nd antenna.

Dual receive relay scan - sub rx scans and tunes main rx to active freq. Stays on that freq until something else found.

Friday, 16 June 2017

Freeholds Top

Yesterday I was in the Manchester area so stopped off on the way home at Whitworth and walked up to the summit of Freeholds Top (SOTA G/SP-011). I'd been up there a couple of times before (2003 and 2006).
I took my Retevis DMR handheld and the Baofeng GT-3 dual band handie, both with their own antennas.
I made one QSO on DMR simplex (438.6125) with G8HIK in Radcliffe and the rest on 145MHz FM. All were in the Greater Manchester area.
I parked at Shawforth, grid reference SD890210.
Just had to restart my PC while editing this post after Windows 10 got a BSOD, at least Blogger saved everything.

Hameldon Hill BBC transmitter site 12km to the north west. Across the valley from Freehold's Top to the west is the Whitworth TV and DAB mast.


 Manchester somewhere in the distance


 I don't think these were here last time I visited



The last photo is a capture from a video I shot on my new "Action Pro Sports Camera" (a very cheap GoPro type thing). 

Friday, 9 June 2017

Huawei Mate 9

Got my new phone last Thursday, a Huawei Mate 9

Side by side with the old Galaxy Note 4. No physical buttons on the front and 0.2" more screen squeezed in.

 The phone came with a case, but I'd already ordered one.

USB-C cable, the first USB-C thing I've ever had, and a Micro USB to USB-C adaptor.
I think the RF performance of the phone is better than the Samsung, it does seem to hold a 3G/4G signal through areas where it would completely drop out before, and maybe 2.4GHz Wi-Fi is also better.
It can also show the channel number of the cell in use and some neighbouring cells, the Samsung never did this (but earlier Galaxy Notes did).
There is space for 2 SIM cards (or one SIM and one Micro SD card) but on the version I got from Three UK the 2nd SIM isn't recognised.

Wednesday, 31 May 2017

1090MHz

Tonight I had a go at decoding aircraft data signals on 1090MHz using an RTL USB TV tuner dongle, RTL1090 and Virtual Radar.
I was just using my usual 50/144/430MHz vertical antenna with this, so it wasn't going to work too well, but I decoded a few planes going over the local area.
Also tried the DAB receiver software SDR-J.
A DAB+ station on the 3rd national multiplex (no local sites, nearest is Winter Hill).
I've ordered a new phone, a Huawei Mate 9, to replace my Samsung Galaxy Note 4 (which is still OK, and the Note 1-3 that I had before that would probably be OK to still be using).
Why not another Samsung?
  • Samsung and Apple's top of the range phones are now about £750. Even over a 24 month contract that's a lot of money just for the phone before they add on any calls and data. There is serious competition at a lower price now (but not 'cheap'), Huawei etc.
  • At the moment there isn't any version of the Note on sale, after the Note 7 was recalled. There was no UK release of the Note 5 either. 
  • Even though the Galaxy S7+/S8+ are big screen phones, things like the curved screen and the new 2:1 aspect ratio put me off. I think real horizontal screen size is more important than getting rid of a few buttons (I liked the 1280x800 screen on the original Note, the Note 2 actually made it worse by going to 1280x720). 
  • With the iPhone 6+, Apple took the 'phablet' form factor into the mainstream (the big iPhone is just as big as a Galaxy Note). I could almost buy one now, except I don't like iOS.
  • I don't think I'll miss the S-Pen very much, it was a novelty but I ended up using it mostly as another way of taking a screen capture. 

Thursday, 4 May 2017

WSPR from Mallorca

A few weeks ago I was in holiday in Mallorca (El Arenal) and took my WSPRLite with me. I'd been thinking about using a balloon to hold up a half wave for the 20m band but didn't see any balloons when I got there so had to rethink.
In the end I used the Snowdonia Radio Company UnUn feeding into the ventilation duct up the side of the hotel, with no idea what the SWR might have been. Some RF did manage to escape though, 106 stations reported me on 14MHz WSPR that week, the furthest being OY1R in the Faroe Islands at over 2500Km away.


We were on the 4th floor, so the feedpoint of the 'antenna' was about halfway up.
I also took my Baofeng handheld to see what other radio activity there was on VHF/UHF. Heard some amateur repeaters in the 70cm band (repeaters over there transmit in the 438-439 MHz range) but they were all digital. For people visiting the island it's a good thing to have digital repeaters that can be linked up.
Repeaters on 438.250 (DMR), 439.200 (D-Star), 438.450 (D-Star). Page with all Spanish 70cm repeaters.
No analogue repeaters or simplex heard at all on the amateur bands, and a lot of activity on other frequencies was DMR.
The FM broadcast band in Mallorca is very busy, with the main broadcast site at Bunyola having 25 different transmitters, and another at Palma with 18. Many transmitters at Bunyola are only 300KHz apart, with a couple at 200KHz spacing!
 The masts at Bunyola, about 25km away to the north.

A few people on HF nearby

Lots of Ubiquiti 5GHz Wi-Fi links

Monday, 27 March 2017

Good VHF/UHF Conditions









On Saturday, conditions on VHF and UHF were really good. Hearing a lot of activity from Ireland, and even signals from as near as Blackpool were a lot better than normal.

The video is just my radio scanning round 2m and 70cm, showing what kind of signals I was getting from some DMR repeaters, the best propagation was to GB7UL on 439.525 at Carrickfergus.

On 145MHz, GB3MP on 145.750 was a bit stronger than normal, you can hear some interference on all the VHF signals, like a clicking noise. This happens at certain times of day, and is on top of the already high noise level - if I turned the squelch down on the FT-7900, it would be showing S3 of noise right across the 144MHz amateur band.

I could hear a repeater on 439.100 which had an Echolink conversation on it, that isn't a repeater frequency used anywhere in the UK for analogue or digital, and the only mention I could find online was a repeater in Germany. I couldn't find any CTCSS tone when scanning for one either.

Friday, 17 March 2017

How Cheap?

Think £20 for a dual band handheld is a bit too much? Well how about £9.36 for two?
http://www.ebay.co.uk/itm/2PCS-2014-UV-5RA-UV-5R-Dual-Band-136-174400-480-MHz-FM-Ham-Two-way-Radio-/332156764896?_trksid=p2141725.m3641.l6368
If you look through enough search results on Ebay for Baofeng radios (either the UV5 or the BF888 single band 16-channel) you find the odd one on sale for ludicrously low prices.

Here are UHF handhelds for under £2 each
http://www.ebay.co.uk/itm/Baofeng-4PCS-Walkie-Talkie-UHF-400-470MHZ-2-Way-Radio-16CH-5W-BF-888S-Long-Range/132121923681?_trksid=p2141725.c100338.m3726&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20150313114020%26meid%3D38c967ad568545deab73661a4b153f52%26pid%3D100338%26rk%3D2%26rkt%3D18%26mehot%3Dpp%26sd%3D332156764896
At this sort of price, even if the battery or the radio was faulty when delivered, the other half would still be worth the money as a spare.

Friday, 3 March 2017

Audio Transformers

I ordered a Ground Loop Isolator from Ebay a few weeks ago for about £2 - a box with 2 audio transformers in it, usually for installing in a car between the line out of a car stereo and an amplifier. I got it for connecting between a radio and PC, in case there were problems with ground loops and other interference.


And here are the transformers inside
I have my Yaesu FT-7900 connected to a Edirol UA-25 USB audio interface using a 6 pin mini DIN to phono cable. One phono plug for discriminator audio (9k6 packet out) and another for normal (voice) audio. The first test I did was to try decoding some DMR using DSD+ software. This normally works OK using the 9k6 packet output.
DSD+ was trying to decode the DMR but there were so many errors it could not even get the correct colour code on a strong signal. Definitely the transformers causing the problem.
I checked their frequency response by looping the UA-25's output back to the input and playing some test tones through it, then comparing with a straight through cable.
The table below shows the insertion loss at each frequency compared to a straight through cable.
The -3dB point is somewhere between 50 and 100Hz, this would be OK for voice and data which used frequency shift keying only within the normal audio bandwidth of a radio, but for DMR (and probably other data modes using the same modulation), this is no good. It cuts off a bit high for music too, at least with a good amp and speakers.

Wearable

Last June I started trying to be a bit more fit and healthy so as well as joining a gym, I bought a fitness tracker "smart watch" device, a Garmin Vivofit 2
It's purely a fitness tracker, it won't show messages or do any syncing with a phone other than to (slowly) transfer my activity data.
But, unlike a lot of other wearables, it uses a non-rechargable lithium cell (CR1632 - not a very common size, couldn't find any in Poundland so ordered some spares online) which can last up to 12 months. I've not had to change mine in the 9 months I've had it. It's waterproof and I've never needed to take it off.
As well as steps, it can measure heart rate (with a chest strap which I've never tried) and sleep (by tracking movement, not by brain waves or anything as clever). I usually keep an eye on steps and distance throughout the day, walking a bit more in my lunch break since I've got it.
At the gym it's sort of useful, some of my gym activity adds to the step and distance count but it's no use on the bike and might not be that accurate on treadmill and cross trainer as the movement isn't natural walking or running. The daily step target varies depending on how well I've done over the last few days, it's usually over 10000 unless I've spent a few days off work doing nothing.
Here are a few screenshots from the Android app, Garmin Connect. I find that to sync the device, I need to start the app, kill it in the task manager and then start it again before pressing the sync button. The app also needs internet access to work at all, it won't even sync offline as all the data is stored on Garmin's servers.


 My best 28 days was around 400000 steps, in the summer.
My phone also has an activity tracker, Samsung S Health, which is always running but I don't take much notice of it as I don't always have my phone with me when exercising. It usually says I've done enough steps each day anyway but I think the target is set to something really low like 6000.

Monday, 27 February 2017

LoRa

200km from a low power 868MHz device?

https://www.youtube.com/watch?v=adhWIo-7gr4

See this video for very long range experiment using LoRa modules. LoRa is a spread spectrum (125KHz bandwidth) data mode which can be received at very low signal levels, and its main use will be for the Internet Of Things - smart meters and other stuff which only needs to transfer a small amount of data. This is all done in licence free bands that are normally used for low power data such as remote controls.

https://www.thethingsnetwork.org/

There is also The Things Network, connecting LoRa gateways around the world which anyone can access (it's a bit like the amateur radio APRS gateway system but for LoRa devices). There are already a few set up in the Liverpool, Manchester and Lancaster area.

The YouTube channel above has instructions on how to build both a node and a gateway for LoRa. 
You can get LoRa modules for the 433(in the amateur band but low power devices are used here), 868(main band in Europe) and 915MHz (USA) bands.

It's interesting to see that there's so much experimenting with radio going on outside of the usual amateur radio bands and organisations. To me, anything that could possibly get more than a few hundred metres is worth trying (further than your average indoor Wi-Fi access point).

Monday, 6 February 2017

WSPRlite

My WSPRlite arrived on Friday, from SOTABeams. A 200mW WSPR transmitter, needing no PC or any cables except power (micro USB) and antenna (SMA).



And while I'm taking photos in the kitchen, here's Friday's tea


One button, one LED. Press the button once at 2 seconds past an even minute to begin the first transmission. I use the Clock Sync app on my phone to get an accurate time via the internet.

I've no permanent HF antennas at home so I tried it in the car, with a Watson Multi Ranger antenna. The mag mount is a bit small for the HF bands but I found it worked OK on 14MHz, with 20 reports in the first hour of use. I powered it from a TP-Link power bank, and at 180mA on transmit and under 50mA waiting, it will last for days on that. My USB power monitor won't measure below 50mA so read zero except when transmitting.
At that low power, most SWR meters won't let you calibrate to full scale, but as long as they have a separate reverse power reading, you can see when the SWR is OK (3:1 would be 25% reflected power, 2:1 9% etc.).
 No connection at all to the car electrics

 The next time I tried it in the car on 14MHz, I got 2 reports from the USA.
Compared to the usual 5 watts I'd been using for years on WSPR when I had a proper HF radio, 200mW (14dB down) needs a bit more effort - 5 watts will work into just about anything with WSPR, especially with an auto tuner. At 200mW an auto tuner might not even start to tune on transmit. I think the mobile whip is just as efficient as a random length of wire.

On Saturday I made my first SOTA chaser contact on DMR (or any digital voice mode). I've made QSOs from summits on both D-Star and DMR before though. When I was scanning round, I heard some activity on 438.6125, so quickly changed over to the DMR radio and spoke to 2W0SEY/P on Moel Famau (G/NW-044).

For tea on Saturday we went out to One Restaurant in Barrow. The last time I'd been there was 3 years ago for my birthday and tried The Challenge of eating a massive burger, hotdog and fries in 45 minutes (and failed). This time I settled for the normal menu
 "Alligator Cooler"
 Piri Piri Burger
Chips, Cheese and Gravy
"The Black Hole"