Date   

Re: Raspberry Pi

Chuck Berry <n7chs.qsx@...>
 

OK, it looks like the R Pi is out.  Has anyone installed "APRS Messengr" on a small (micro) computer and a SDR Transceiver with small footprint?  Space is critical for my application.  Thanks, Chuck N7CHS

On 7/26/2019 3:51 PM, Chris Moulding wrote:
It's not possible to port APRS Messenger to any other operating system other than Windows.

APRS Messenger is written in Visual Basic 6 (VB6) and uses several DLL libraries that will only run with VB6.

It is possible to run APRS Messenger under WINE on Ubuntu Linux but as there is no support for USB it has to rely on VOX to key a HF transmitter. GPS and TNC use via USB doesn't work either.

I know that earlier versions of the Raspberry Pi couldn't run WINE but I've not followed the latest version of the Pi to see if it can.

Regards,

Chris


Re: Raspberry Pi

Chris Moulding
 

It's not possible to port APRS Messenger to any other operating system other than Windows.

APRS Messenger is written in Visual Basic 6 (VB6) and uses several DLL libraries that will only run with VB6.

It is possible to run APRS Messenger under WINE on Ubuntu Linux but as there is no support for USB it has to rely on VOX to key a HF transmitter. GPS and TNC use via USB doesn't work either.

I know that earlier versions of the Raspberry Pi couldn't run WINE but I've not followed the latest version of the Pi to see if it can.

Regards,

Chris


Re: Raspberry Pi

N5VMO Pat
 

Chuck .... I was wondering the same thing or maybe port it over to R Pi Linux OS ( prefered =)

On Fri, Jul 26, 2019 at 2:37 AM Chuck Berry <n7chs.qsx@...> wrote:
Has anyone had success running "APRS Messenger" on a Raspberry PI? 
Thanks, Chuck N7CHS


--
73's Pat  N5VMO



Raspberry Pi

Chuck Berry <n7chs.qsx@...>
 

Has anyone had success running "APRS Messenger" on a Raspberry PI?  Thanks, Chuck N7CHS


For sale: HF Active Loop Antenna...version 2 with VLF coverage

leslie norton
 

Bought it late last year to hopefully try and null out VDSL but no matter where i put it, on the ground or as now up above the house. I cannot null it out.
Works extremely well especially on Low bands (I can null out on low bands but as my interest is in HF its just a waste)

Now the glitch!!

I have recently had my ladders stolen but did buy a telescopic ladder and it goes up almost where its needed but im not good on ladders plus the pole im using is a slot in type and stuck so no way to lower it. Im prepared to take £100 if you can help me get it down, plus i'll include 20m of cable.

Its in great condition but just not for me.

Location is NE61 5XP (Lynemouth, Northumberland)

Direct email is: gm4jnw@...


Summer LF conditions !

WQ2H <wq2h@...>
 

Even though we're about 1300' AMSL, we're also totally surrounded by heavily forested terrain (oak, sugar maples, beech, etc.) - so it's always tough going this time of year.

BUT, we had our first -34 dB this morning (with the CCW active vertical dipole): 

2019-07-21 01:06      K3MF      0.137411      -34      0      FM19sr      1      WK2XAH      FN32xv      510      45

Fall and winter simply can't come fast enough (skiing AND radio) !

73
Jim, WQ2H/WK2XAH


Re: LED brightness and reception question

leslie norton
 

Thanks Chris

I might try it at about 2M then, well away from the house, at the moment its poking just above the roof.
I suppose the target would be to hear a friend of mine on 5mhz as i can only just hear him on my longwire, difficult to say with the 5mhz band which would be better as he is 287 miles away, its just a matter of experimentation. 287 miles may JUST come in as NVIS on 5mhz so may be worth a try.

The pole i have it on at the moment is right next to the house but i have no way comfortably of mounting it elsewhere.

Appreciate your time as know your a busy man.

BTW: just as a compliment the loop really stood up well to the storms over winter, saw it wobblying away but with it being flexible it stood up well, the same couldn’t be said for a rigid wooden pole that my neighbour hangs flags on from time to time.

Cheers again
Les

On 12 Jul 2019, at 13:43, Chris Moulding <chrism@...> wrote:

It all depends on what you want to monitor on HF.

The loop antenna is horizontally polarised so if you want to hear very distant stations then mount the antenna high as you would a horizontal dipole or HF beam to get additional gain from the ground reflection.

Some years ago I had the prototype loop mounted 10m above ground level and it gave excellent results on HF DX. I used it to feed the WebSDR station I had running at the time and during the Nepal earthquake my station was the only WebSDR station that could receive the one Nepalese radio amateur transmitting to the outside world. I found that out when I got a phone call to tell me that the WebSDR server had gone down due to the number of listeners on it!

The theory about mounting the antenna close to the ground is because it deliberately doesn't get any additional gain from the ground reflection. This can be a good thing because the ground reflection may be in or out of phase with the direct signal depending on the elevation angle. Mounting the antenna high for long distance work may give a peak in one direction but at the expense of a deep null somewhere else.

Mounting the antenna 2 to 3m high eliminates any nulls in the radiation pattern so you can hear everything from overhead (NVIS) to close to the horizon. I don't know your location but if you mount it low pick a location as far away from other clutter (trees, buildings, electrical wiring, telephone wires etc) as possible for best results. Many professional HF receiving arrays use multiple loop antenna at 2 to 3m high but use phasing lines between them to tailor the radiation pattern towards the target station.

Regarding signal level compared to other antennas it's better to compare the signal to noise rather than the overall S meter reading. It would be very easy to add extra amplifier stages to the loop antenna so that it "appears" to be the best because the output level is high. It is actually better if the level is lower with the noise lower still. Don't forget antennas such as a resonant dipole or yagi are quite sharp in bandwidth. An end-fed antenna (unless it's a terminated version) also has resonances. As the loop antenna is wideband if the amplification is such that is equal to or greater than what you expect from your end fed antenna on the band it's resonant on then the entire HF spectrum will be hitting the front end of your receiver with possible consequences of overload or intermodulation products. In this case a little less output is a good thing.

Regards,

Chris


Re: LED brightness and reception question

Chris Moulding
 

It all depends on what you want to monitor on HF.

The loop antenna is horizontally polarised so if you want to hear very distant stations then mount the antenna high as you would a horizontal dipole or HF beam to get additional gain from the ground reflection.

Some years ago I had the prototype loop mounted 10m above ground level and it gave excellent results on HF DX. I used it to feed the WebSDR station I had running at the time and during the Nepal earthquake my station was the only WebSDR station that could receive the one Nepalese radio amateur transmitting to the outside world. I found that out when I got a phone call to tell me that the WebSDR server had gone down due to the number of listeners on it!

The theory about mounting the antenna close to the ground is because it deliberately doesn't get any additional gain from the ground reflection. This can be a good thing because the ground reflection may be in or out of phase with the direct signal depending on the elevation angle. Mounting the antenna high for long distance work may give a peak in one direction but at the expense of a deep null somewhere else.

Mounting the antenna 2 to 3m high eliminates any nulls in the radiation pattern so you can hear everything from overhead (NVIS) to close to the horizon. I don't know your location but if you mount it low pick a location as far away from other clutter (trees, buildings, electrical wiring, telephone wires etc) as possible for best results. Many professional HF receiving arrays use multiple loop antenna at 2 to 3m high but use phasing lines between them to tailor the radiation pattern towards the target station.

Regarding signal level compared to other antennas it's better to compare the signal to noise rather than the overall S meter reading. It would be very easy to add extra amplifier stages to the loop antenna so that it "appears" to be the best because the output level is high. It is actually better if the level is lower with the noise lower still. Don't forget antennas such as a resonant dipole or yagi are quite sharp in bandwidth. An end-fed antenna (unless it's a terminated version) also has resonances. As the loop antenna is wideband if the amplification is such that is equal to or greater than what you expect from your end fed antenna on the band it's resonant on then the entire HF spectrum will be hitting the front end of your receiver with possible consequences of overload or intermodulation products. In this case a little less output is a good thing.

Regards,

Chris


Re: LED brightness and reception question

leslie norton
 

Thanks Chris

I never ever listen to MW but have just tried MW on my FTDX3000 on the loop and as you say there is a deep null so thats fine, so its working ok on MW

I tried my usual bands 3.5/5/7.5/14mhz and no nulls at all and signals way down on my longwire.

Wondering if i should remove the loop and put it somewhere without the rotator as i could use the rotator for 2m band with my 2m rig.

Now the next question: sorry to ask so much.

When i used the Wellbrook i was told it would perform better near the ground, that turned out to be true, is the CCW loop the same, if so i could just mount it static on my wooden shed, it would be around 5-6ft off the ground.

I am talking for HF use now as i don’t go to MW

Thanks
Les

On 12 Jul 2019, at 10:15, Chris Moulding <chrism@...> wrote:

From the photo the red LED brightness is what it should be in normal use.

If the cable is shorted then the LED glows at full brightness.

The red LED measures the voltage dropped across the large 22R resistor. The resistor also acts to limit the fault current into a shorted cable protecting the power supply and cables.

Regarding the null performance of the antenna have you tried it on a local medium wave station that is in ground wave range. In that situation you should see a very sharp deep null. On HF it's difficult to null out signals due to refraction off multiple layers in the ionosphere causing the signal to appear at varying elevation heights and over a wider bearing.

Regards,

Chris


Re: LED brightness and reception question

Chris Moulding
 

From the photo the red LED brightness is what it should be in normal use.

If the cable is shorted then the LED glows at full brightness.

The red LED measures the voltage dropped across the large 22R resistor. The resistor also acts to limit the fault current into a shorted cable protecting the power supply and cables.

Regarding the null performance of the antenna have you tried it on a local medium wave station that is in ground wave range. In that situation you should see a very sharp deep null. On HF it's difficult to null out signals due to refraction off multiple layers in the ionosphere causing the signal to appear at varying elevation heights and over a wider bearing.

Regards,

Chris


Re: VLF/LF/HF Active Vertical !

Chris Moulding
 

Having the Sentinel 4 receiver in the workshop running WSPR 24/7 is proving very useful.

I did some listening on 137 kHz with the VLF/LF/HF Vertical with good results.

Over the last few days I've run tests with the WSJT-X program using band hopping from 160m to 10m to compare the VLF/LF/HF Vertical with a new revised version of the Broadband Active antenna I'm working on using a new grade of ferrite to isolate the antenna from the feeder.

Previously the performance of the Broadband Active antenna wasn't quite as good on HF as the other antennas we make but with the revised design it equals the VLF/LF/HF Vertical on 160m and above. This was proved by listening to the WSPR transmissions.

This evening I'll set it listening on 474 kHz with the VLF/LF/HF Vertical. I've never listened on that band so it will be interesting to compare with 137 kHz and the other HF bands.

Regards,

Chris


LED brightness and reception question

leslie norton
 

Since i bought the HF Active Loop Antenna...version 2 with VLF coverage, after selling my Wellbrook loop, ive never been really satisfied with the reception or nulling even though its above the roof height on its own pole on a rotator, I just basically accepted poor performance UNTIL i went back to read the FAQ's and one section says the red LED should be dim and if not it indicates a short on the lead.
I have taken a photo of the box and how dim is dim because it comes over as almost as bright as the green LED, the photo doesn't show it quite as bright as it is in real life but does show its not what i would call dim, the green LED somewhat overpowers the RED one so it doesn't appear as bright.
I have changed the CAT cable and its the same brightness.
I enclose a photo for your views.
Also is there any tests i can do?
Thanks
Les


Re: VLF/LF/HF Active Vertical !

WQ2H <wq2h@...>
 

Just another update on the 630m side (from FN32vx).

Last night was the first night I monitored WSPR2 and JT9-1 with the CCW on 630. Extraordinary activity here on JT9-1 and -2, with several stations coming in at -10 dB from well over 1000 km away. Puzzling because we did have heavy rain and thunderstorms around us last night. For a while there I thought I was watching FT8 on 20m !

In the next few weeks I should have my 630 Tx capabilities up and on the air (thanks in part to K5DNL). I will advise of any QSO's I can muster.

Chris - great WSPR2 spots on 137, I see you have several at over 1000 km. I know it's a stretch - but I will advise once the 137 beacon is back on the air.

73
Jim, WQ2H / WK2XAH


Re: Radio

Jon Wornham
 

Hi Chris

Afraid I went for the SDRplay Duo as my main interest was airband VHF/UHF.   It works very well but it's a wee bit complicated for my poor brain :-)

Cheers
Jon

On 04/07/2019 19:10, Chris Moulding wrote:
In theory it's possible to receive on the third harmonic of the mixer injection frequency with a suitable bandpass filter to reject the fundamental response.

I recall doing this with the original Sentinel SDR receiver to reduce the spurious responses from the DDS synthesiser used in that receiver.

So applying the idea to the Sentinel 4 receiver design which covers up to 64 MHz it would be possible to extend the frequency coverage up to 192 MHz with extra relays and filters. This would cover the VHF air and marine bands.

It would need a completely new PCB design but it is technically possible.

Whether it's commercially viable is a different matter as most SDR receiver users today appear happy to use RTL-SDR or SDRPlay receivers with 8 or 12 bit receivers giving limited dynamic range compared to the 16 bit codec used in our receivers. In practice the receiver front end is suitable for use with 24 bit 192 kHz sound cards using the IQ output so wideband VHF FM reception is certainly possible.

The RF filtering on some of the SDR receivers barely meets the requirements to be called a filter.

If I was going to design a completely new SDR receiver I would go all out for a good RF design with excellent RF filtering and similar levels of isolation to the existing CCW receivers to give 24/7 all weather performance. However it wouldn't be cheap!

I expect that it would meet the needs of commercial and military customers but are enthusiasts looking for something like this?

I would be interested to hear opinions from everyone on this. Is it worth doing or are you all buying SDRPlay receivers?

Regards,

Chris



Re: Radio

Chris Moulding
 

In theory it's possible to receive on the third harmonic of the mixer injection frequency with a suitable bandpass filter to reject the fundamental response.

I recall doing this with the original Sentinel SDR receiver to reduce the spurious responses from the DDS synthesiser used in that receiver.

So applying the idea to the Sentinel 4 receiver design which covers up to 64 MHz it would be possible to extend the frequency coverage up to 192 MHz with extra relays and filters. This would cover the VHF air and marine bands.

It would need a completely new PCB design but it is technically possible.

Whether it's commercially viable is a different matter as most SDR receiver users today appear happy to use RTL-SDR or SDRPlay receivers with 8 or 12 bit receivers giving limited dynamic range compared to the 16 bit codec used in our receivers. In practice the receiver front end is suitable for use with 24 bit 192 kHz sound cards using the IQ output so wideband VHF FM reception is certainly possible.

The RF filtering on some of the SDR receivers barely meets the requirements to be called a filter.

If I was going to design a completely new SDR receiver I would go all out for a good RF design with excellent RF filtering and similar levels of isolation to the existing CCW receivers to give 24/7 all weather performance. However it wouldn't be cheap!

I expect that it would meet the needs of commercial and military customers but are enthusiasts looking for something like this?

I would be interested to hear opinions from everyone on this. Is it worth doing or are you all buying SDRPlay receivers?

Regards,

Chris


Re: VLF/LF/HF Active Vertical !

WQ2H <wq2h@...>
 

Chris, from my understanding, 1W EIRP on 137 is gargantuan.

Using the VK1SV calculator - the Hafler P3000 at 400W TOP is <500mW EIRP after going through the variometer. That places the voltage ~17kV.

Nice thing about that is that the corona arcs self-prune the adjacent foliage. LOL!

Antenna work here is ongoing - but as you would expect, the increments of progress are small. I'll be back on Tx in a few weeks.

73
Jim, WQ2H / WK2XAH


Re: Radio

Bob G3REP
 
Edited

On Mon, Jul 1, 2019 at 10:03 AM, Chris Moulding wrote:
The maximum frequency of the SDR-4+ receiver is 70.5 MHz so it will not cover
the 118-136 MHz air band.
Except with a wideband converter, plus a BPF ;-)
Next Project ?

Bob
G3REP


Re: VLF/LF/HF Active Vertical !

Chris Moulding
 

Thanks for the report on what you are hearing.

I've set up one of the VLF/LF/HF Active antennas at the workshop feeding one of the prototype Sentinel 4 receivers through a 150 kHz low pass filter to remove the LW and MW broadcast stations.

Best so far was hearing WSPR transmissions on 137.5 kHz from stations in Germany and Spain. The only problem was that the 4G modem we use in the workshop for internet access fell over that night so the spots from G4HYG/RX2 didn't get to the WSPRnet database.

I'm rather surprised how far 1W effective radiated power at 137.5 kHz can get.

Regards,

Chris


Re: VLF/LF/HF Active Vertical !

WQ2H <wq2h@...>
 

Just an update:

Using this CCW antenna I (as WK2XAH) snagged a personal best of 3594 km 4-FSK (WSPR2) Rx from WH2XND on 137.5 kHz. Plenty of good activity on 474 also (up to about 800 km), but this was a real surprise. Also spent a few hours on a Sunday morning on NDBs - picked up about 30 new ones mostly from the Canadian Maritimes and northern Quebec. Good stuff !

73
Jim, WQ2H / WK2XAH







Re: Radio

David Dudley
 

Thanks Chris

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