SDR - newbie and how to make a home made antenna??

dc99

Hi,
SO I got the NooElec bundle (the USB SDR receiver and the Ham it up up converter (or is it down converter??).

It comes with a few small antennas and a 9:1 Balumn.

I’m not expecting much from the small antenna - great for receiving Broadcast FM, but - well thats not what I git the SDR for.

So What can I do to get some around reception? I’d love to start getting some HF (pardon me if i mix up my terminology etc. as I’m kinda new at this...).

Many years ago I was “big” into CB and the DX’ing on that (SSB etc). Made quite a few connections....anyway If I use the Balumn, what length of wire do i need to get some good reception?

Does it need to be single core wire or will multi core conductors do?
What length for each “side” of the Balumn? Is 2m to small?
Will i need different lengths for HF / VHF / UHF?
Have i any chance of receiving transmission if I keep this home made antenna indoors?

Any help and advice would be great - thanks

jmcc

HF (less than 30 MHz) is going to be very noisy in an urban environment.

The simplest antenna to build is a half wave dipole. This is essentially two quarter wavelength bits of wire, a terminal connector and some coaxial cable. Mounting it outside would be best and it may also be neccessary to use a piece of perspex or plastic to provide strain relief for the coax and the wires. (You might have even made a few for CB back in the day.

For VHF, a dipole will work too and may be far easier to build and mount due to the size reduction due to the higher frequency. It is also possible to experiment with different antenna types such as coaxial collinear antennas (basically a few pieces of coaxial cable cut and joined together). A coaxial cable Bazooka antenna that is just a piece of coax with a quarter wavelength of the braid peeled back over the coax can also provide some good results.

CB frequencies seem to be rather quiet these days (low sunspot activity). There are signals on HF that should be receivable even inside a house.

Single core cable such as bell wire (most electrical shops should have it) or muticore cable will work. Even the rolls of plastic coated garden wire for a few Euro that Aldi and Lidl sell can provide signals. (They are iron rather than copper wire but this doesn't really matter with receiving signals.)

Even at ground level inside, it is possible to receive HF, VHF and UHF. The main problem on HF is that the spectrum will be saturated with interference from power supplies, TVs, computers and monitors.

With the antenna supplied, you will be able to pick up HAM radio repeaters, aircraft transmissions and aircraft location transponders. Long wire antennas for HF might provide some better reception and that 9:1 balun is intended to provide a better match for such antennas. The advantage of dipoles cut to frequencies is that they often provide a better impedance match and can be fed with coaxial cable.

The Ham-it-up upconverter is a nice little device and does work. It also, if it is the later model, has its own RF noise generator which allows you to build and tune filters and other such devices easily.

Multi-band antennas such as discones might work but for HF, wire antennas for particular bands may be better.

The main issue with SDRs is that the SMA connectors are not widely available in local retailers. (It is possible to order them from Radionics/RS in Dublin.) It might be a good idea to buy a few BNC to SMA or F to SMA adaptors so that you can work with commonly available coax and connectors.

There are also so good groups on Facebook for antenna design and for SDRs.

Regards...jmcc

I’d recommend a proper receiving antenna such as the wellbrook loops and Bonito loops , the Bonito Megaloop FX or Boito Megadipol antennas are great or if you have the space then Bonito have a passive 15 meter loop that is a lot cheaper than the active antennas but would provide good quiet reception.

The problem with wire antennas is that while they are good for transmitting they can add quiet a lot of noise for receiving and/or they are good on very few bands and introduce a lot of noise on others.

The antennas listed above are broadband antennas that will cover the entire LF-fM.

I have two Kiwi SDR’s with the Bonito Megaloop FX 10 meter loop version and Megadipol and you can listen to them here.

[URL="emeraldsdr.ddns.net:8074"]emeraldsdr.ddns.net:8074[/URL]

[URL="emeraldsdr1.ddns.net:8073"]emeraldsdr1.ddns.net:8073[/URL]

Oh and I almost forgot the Bonit MA305 , this antenna is tiny and will blow many wire antennas away, I’m still amazed every time I use it.

Good quality coax is also essential and grounding of this little antenna helps a lot, H155 coax would be much better coax to use.

You could be disappointed with some wire antennas so if you can at all the above antennas are highly recommended.

Loop antennas are also less susceptible to man made noise generated from LED lights, laptop power supplies, phone chargers, and some old flourescent back lit tv’s.

Upgrading to the sdr play should help a lot in time when you get the taste for this hobby lol, it’s a very good receiver and probably a lot better than the nooelec sdr.

Have a listen to my kiwi’s in the links above and let me know what you think.

dc99

Hi,
Thanks for some great info. The Bonita MA305 looks exactly what I’m looking for - except for the price :-(

Its a lot more that I was planing to spend, without knowing if it will work out for me....

So if I can impose on you guys some more?

Say I get the Bonita, where do I need to mount it.

I live in Tralee, with mountain to the south of the town.

I reckon I need to do more than hang it out the window? It would need to be pole mtg’ed? Would it need to be above the roof line of the house? I have loads of space around the house, I live about 2km west of the town, so am not really urban area, there are houses around alright.
So with the Bonita, needs to be above the roof line? (Wife will go nuts lol).
I seem to remember that having an antenna near something - affect the reception?” Unfortunately for me my computer is sited in the room facing the raod...
What about a long wire with the Balun? What length of wire do I really need? Do both side need to be the same length? I can run these out the window.

If I did go for a long wire what way do I need to hang it?

Sorry - really cramp at understanding this stuff - that’s why the bonita sound good to me, except for the price that is...

Any help is appreciated. Thanks

dc99

dc99 wrote: »

Hi,
Thanks for some great info. The Bonita MA305 looks exactly what I’m looking for - except for the price :-(

Its a lot more that I was planing to spend, without knowing if it will work out for me....

So if I can impose on you guys some more?

Say I get the Bonita, where do I need to mount it.

I live in Tralee, with mountain to the south of the town.

I reckon I need to do more than hang it out the window? It would need to be pole mtg’ed? Would it need to be above the roof line of the house? I have loads of space around the house, I live about 2km west of the town, so am not really urban area, there are houses around alright.
So with the Bonita, needs to be above the roof line? (Wife will go nuts lol).
I seem to remember that having an antenna near something - affect the reception?” Unfortunately for me my computer is sited in the room facing the raod...
What about a long wire with the Balun? What length of wire do I really need? Do both side need to be the same length? I can run these out the window.

If I did go for a long wire what way do I need to hang it?

Sorry - really cramp at understanding this stuff - that’s why the bonita sound good to me, except for the price that is...

Any help is appreciated. Thanks

Ask all the questions you want , that's how we learn, I'm still trying to understand it all. I am studying a bit for my Amateur radio licence in May and plan to do a lot more experimentation.

Wire antennas are good for transmitting , ideally you would have an antenna cut for the band of interest but that would be a lot of antennas so you have to compromise.

Some Hams have several antennas for different bands some have wire antennas such as Dipoles and vertical antennas which are good for long distance ( called DX ) Dipoles would then cover smaller but still significant distances. There are of course other antennas.

Now here's the issue for SDR's.

SDR's need a broadband antenna to cover Long wave all the way to 30 Mhz or the HF part of the spectrum if this is your interest. There's lost to listen to.

However, this is mainly for my Kiwi SDR's because they are online and so it must be capable of covering a very wide range of frequencies and it must have pretty low noise, the antenna is crucial to getting good results.

For you , you can use a long wire , say 80 meters in length and get it as high as you can. Use trees, string up rope over a branch and get insulators and tie rope to insulator and wire to the other side of the insulator and same for the other end then bring the wire down to the ground and attach to Coax, get the shield part and bury it to a earth rod, use 2 or 3 earth rods that you would get in an electrical shop, bond them together ,this is essential to prevent static build up and will help prevent noise and also safety against lightning.

You can hang it as a sloper, high end to low end but try keep as much as high as you can.

Next you can experiment with baluns which are really only necessary for transmitting because the wire will have a very high impedance and you would need to match it to 50 Ohms of the transmitter.

The balun or Unun can help to reduce noise and you will most likely need one if you are receiving a lot of noise, again, proper grounding is essential.

Or you could buy this below and you're all ready to rock.

https://www.moonraker.eu/moonraker-md37-skywire-shortwave-wire-kit?___store=english&refSrc=311&nosto=nosto-page-product1

One issue is that your sdr "may" crap itself with strong signals, the SDR Play is much better at coping with strong signals. Sure signs of over load are signals appearing in places they're not actually transmitting. Higher quality SDR's can deal with strong signals much better.

Remember get it high whatever length of wire you use, get it as far from the house as you can to prevent it picking up interference. And ground that coax braid with 2-3 Earth rods bonded together.

Check out this wire antenna from a well known reputable company.

https://www.hyendcompany.nl/antenna/swl_antenna/product/detail/28/SWL_Antenna_0_3_30MHz/single#main

The Bonito MA305 is pricey but it's bloody tiny , the antenna itself is only 45 CM and whatever trickery they did it works as well or better than a lot of wire antennas that are many many meters in length.

Of course you can experiment with your own first.

Did you listen to my sdr's ?

Sorry , I made a mistake , the Bonito MA305 antenna is only 22 cm long , yes you read that right , incredible.

dc99

Hi Yes Mad lad- I tuned into your SDR, but didn't spend too much time on them - trying to scan up and down n my nooelec....I went back to using the supplied short whip antenna that came with the SDR, the longer black one.
I can receive LW commercial stations down below 5mhz, but nothing above this (except for irish commercial station on "normal" fm).

So the Bonita - where does that need to be sited? High up as well? Or would sticking it out the window get me something to tune into?

I saw on youtube some guy warping it around a hand rail of a hotel balcony.....

The long wire is what I thought would be a good all rounder - but can now see that your saying it should be (if possible to get best reception) tuned to a particular band/frequency?

I also see Bonita have some cheaper solutions?? the Boni-whip for instance??


Thanks

dc99

dc99 wrote: »

Hi Yes Mad lad- I tuned into your SDR, but didn't spend too much time on them - trying to scan up and down n my nooelec....I went back to using the supplied short whip antenna that came with the SDR, the longer black one.
I can receive LW commercial stations down below 5mhz, but nothing above this (except for irish commercial station on "normal" fm).

So the Bonita - where does that need to be sited? High up as well? Or would sticking it out the window get me something to tune into?

I saw on youtube some guy warping it around a hand rail of a hotel balcony.....

The long wire is what I thought would be a good all rounder - but can now see that your saying it should be (if possible to get best reception) tuned to a particular band/frequency?

I also see Bonita have some cheaper solutions?? the Boni-whip for instance??


Thanks

You don't really need to tune a long wire for receiving but it does need to be long to get decent reception.

For transmitting tuning is crucial although a common misconception is that an antenna tuner tunes the antenna, it doesn't , the tuner just matches the mismatched antenna ( for the particular Frequency ) to the transmitter which is crucial, if the antenna is not resonant for the frequency the tuner won't make it resonant if that makes sense it just means that the transmitter will be happy because now it sees a 50 Ohm load or as close as possible.

For transmitting it's much better to have a longer wire and then use the tuner because you'd get much better results transmitting on 80 meters with an 4 meter length of wire than 10 meters which would give poor results.

Then you can tune to other bands on that same wire much better than if you started with say 20 meters of wire and tried to tune it for 80 meters band.

So for your SDR,

Try a random length of wire, start with 20 meters, get it outside, this is crucial, outside and high as possible , tune around and then ground the braid for the coax to a couple of earth rods in the ground, this is also crucial and essential.

Then you can get a 9:1 Unun and connect that up and see the difference it makes.

You can also get a portable shortwave radio such as a Tecsun PL-660 and see the difference a random length of wire makes when connected to the telescopic antenna that is connected to a tree and up high as possible, the difference is amazing.

Connecting the random wire to telescopic antenna of a portable shortwave radio will work a lot better than connecting it to an SDR which is designed to take a 50 Ohm proper antenna.

You could also try this passive antenna, meaning it has no pre-amplifier , it uses 15 meters of wire and it shows you a diagram of the way you can connect it up.

https://hamradioshop.net/en/Antennas/H-Field-active-Loop-Antennas/Paloran-200-passive-Loop-Antenna.html

You can also connect it up in a tree, wrap it around a few branches and try make it into a loop.

If you have two tall trees you can get a rope over a branch out of each tree, and make a line to attach the loop antenna.

179 Euro's excluding shipping and good H155 Coax is not cheap but it will provide excellent results but first experiment with wire antennas and then log into Both my SDR's again and compare and this is the performance to expect with a proper antenna, my antennas are only up about 20 feet off the ground.

If you live in an area where there is not much electrical interference then the Bonito MA305 with it's unbelievably tiny 22 CM antenna will seriously blow you away. I have mine mounted about 25 feet high cable tied to a branch in a tree.

Later I will post a pic of it, you wouldn't even see it especially when the leaves are out.

Certainly the MA305 Antenna is super easy install but it needs a good ground and I will show you what I did later.

Get a portable radio such as the Tecsun PL-880 or PL-660 Both can pick up the Amateur radio bands, the PL-880 is newer and more expensive both are good radios except the PL-660 is very poor receiving LW/MW where the PL-880 is good at Receiving MW/LW.

If you got lots of noise from electronic devices then the loop antennas would be better.

The antenna supplied with your SDR won't be really good for much except local FM.

Get your antenna outside , as far from the house as you can or any house and up as high as you can.

Radio is a fun hobby and trying to pick out far distant signals is fun, it provided me with endless hours of entertainment.

Study for your Ham radio license and book the exam for May and then the real fun will start, better to have the license than want it but book it fast. Go to IRTS.ie all the info and study material is there.

Here's the Bonito MA305 in a Birch tree, see if you can see it :-)



The grounding rod also got form Bonito.



Zoomed in. I'll upload pics of the other antennas later.

Hey dc99,

any luck with the sdr and antenna ?

dc99

Hi,
I’ve put it on hold for a short while. Jobs to do around the house.....
Still tempetyed with the Bonita thing though.....must get my head around the earthing arrangements though as well.

dc99

dc99 wrote: »

Hi,
I’ve put it on hold for a short while. Jobs to do around the house.....
Still tempetyed with the Bonita thing though.....must get my head around the earthing arrangements though as well.

Try to determine first whether you have a lot of local noise which the MA305 might not like , if you do then the Loop antenna would be a better option, the Paloran 200 passive Loop.

You won't have to earth the Loop but can if you want.

dc99,

Any update on your antenna/SDR setup ?

I got the Bonito MA305 online now via sdr console.

You can download sdr console here ( the 64bit version )

https://www.sdr-radio.com/Software/%F0%9F%92%BEDownloads

Install it, open it and click on "select radio"

On the bottom right of the window that pops up click on "definitions"

In the next window click on " Search "

Then click on "V3 Server"

Next is to look for my radio server, "Emerald SDR 3 Carlow"

This will give you a good idea what to expect from the MA305 Bonito antenna, it's a super antenna and provides incredible performance for only a 22 cm long antenna !

I have some issues, the SDR Console server is a bit buggy, if you get audio and waterfall stuttering try reboot your PC, works for me.

I got interference on LW and some of MW but to a much lesser extent on MW due to the Laptop power supply, it unfortunately wipes out a lot of LW.

I also got interference from ESB Pole which I need to get sorted which effects a lot of the Shortwave bands ( intermittently )

When selecting the radio it gives an option to select "bandwidth" so try select 192 Khz or less , less will use less internet bandwidth my end which can also mean less stuttering if my internet isn't working so well.

I'm using an old Dell Core i5 Laptop and it is working well with this and the beauty if SDR console is that while it uses much more internet bandwidth than the Kiwi it offers a proper full SDR experience and the Audio quality is much better.

DC 99 did you listen to the sdr console I had up with the MA305 ?

I took it off line due to the old dell core i5 generating too much noise especially on 80 meters ham band and SDR console has some bugs I didn't like.

I'm now going to set it up on an old Odroid Xu3 lite I have lying around, it's similar to the Raspberry Pi only much faster. So if anyone is interested in raspberry Pis check out the Odroid's, they are more expensive but much faster.

Setting all this up in Linux is a right pain in the ass as is anything to do with linux !

I'm going to use Airspy's Spyserver server which will work perfectly on the Odroid or even Raspberry pi but the Odrooid will have more CPU power.

It will also greatly reduce internet bandwidth used/needed.

The noise reduction on sdr sharp is amazing.