simple indoor test antenna recommendations for truSDX

[dougjeff]

Hi All

I am a new ham this year making my first steps expanding from VHF to HF with truSDX. I think this is an amazing project and wanted to start by saying thanks to all and especially Manuel & Guido for this cool way to try HF.

As I mentioned I am a new ham and was looking for a suggestion on an antenna that I can use to test the truSDX kit. Ideally something that I can build, use for testing and some initial contacts and ideally something that I could use for POTA in the future. I have tried receiving with a random length of wire. Rolling through 80-20m I hear lots of noise, but no CW or phone. I am not sure if I have a problem with the radio, or I just need a real antenna!

Thanks in advance,


73
Doug
VA7JDJ

[Luca66]

Hello and welcome.
I recommend a simple EFHW antenna and a toroid impedance transformer. I do not recommend indoor antennas.
Have fun

[gatorjj]

The simplest thing to start with indoors would be a 20m dipole. It won't work great but you should at least be able to hear some things on 20m and probably make a few contacts.

The first antenna I put up this year was a dipole in my attic just to test things out, made a good number of contacts even at 5 watts before getting around to putting something up outside. Just a couple thin speaker wires and some coax to the radio. Higher the better applies even inside!

73

J.J. KF4VE

[Luca66]

The simplest thing to start with indoors would be a 20m dipole. It won't work great but you should at least be able to hear some things on 20m and probably make a few contacts.

The first antenna I put up this year was a dipole in my attic just to test things out, made a good number of contacts even at 5 watts before getting around to putting something up outside. Just a couple thin speaker wires and some coax to the radio. Higher the better applies even inside!

73

J.J. KF4VE

Hallo jj
I'm sorry but I totally disagree with your opinion.
An efhw antenna is in fact a single dipole much easier to place also and above all outdoors.
There is absolutely no comparison to be made between an indoor wire antenna and an outdoor wire antenna.
We are working with qrp powers. So the attenuation of the walls of the roofs is very important.
73 Luca

[gatorjj]

Hallo Luca,

While I absolutely agree outside is better, our new ham friend Doug asked about a simple indoor test antenna to test with

Nothing would be simpler inside than a basic dipole, just coax + wires with no balun or unun needed. Unless Doug has a metal roof or lives in a steel building it should hear and get out even with a few watts, I know mine did.

Now if Doug is really gearing up to mainly do POTA, then yes I would absolutely recommend EFHW as the simplest antenna for that! Actually I use a homebrew telescoping vertical for POTA, but that wouldn't work inside

[Luca66]

Hi j.j. For a moment, while reading your message, I thought that the foundations of radio amateurism had collapsed terribly.

Ok, I understood your suggestion for our new friend and I must say that for a simple test even a dummy load could be enough or if he wants to try connections then a dipole loaded with coils, to shorten the physical length or a magnetic loop. In any case, good experiments.
73 Luca

[gatorjj]

Hi j.j. For a moment, while reading your message, I thought that the foundations of radio amateurism had collapsed terribly.

Not on my watch!

Doug, I decided to try my (tr)usdx inside with a short length of wire and I can't hear anything either, except faintly the 20m FT8 (14.074) which is probably the most reliable place you could try to listen. Having a resonant antenna is going to be your friend, indoors or out!

73
J.J, KF4VE

[dougjeff]

Thanks for the feedback

I appreciate the ideas. EFHW is likely to get the nod for outdoor use. The simplest 20m antenna that I think I've seen so far is just made from a piece of RG58, with the shield stripped back for a 1/4 wavelength. I will add loops to make an airwound choke at 1/2 wavelength. This is easy to make, inexpensive and will work to test if I am able to Rx/Tx.

Happily I live in a house without metal siding or roofs, so should be good to go. I will buy a 15-20m piece of RG58 and try that out first. On to the EFHW after that!

Thanks so much,
73

Doug
VA7JDJ

[YO5CSA]

Also you can try a magnetic loop... Is a little bit more challenging to make it, but you will have a small antenna and you can learn a lot on the way.
I have one, as you said, mainly for testing purpose, on 40m, tuned only for FT8 frequency, and it is indoor. I've had a lot fun with it, and with (tr)uSDX it was a bit challenging, but when you realize that with 2-3W, with an indoor antenna you can make contacts...

73!

[Constrainted]

1. Speaker-wire dipole, as KF4VE suggests.
2. A tuner if you want to venture off resonance.
3. Consider using http://websdr.org to find a signal you want to tune on your truSDx. My frequency was about 340 Hz high.

Have fun!

[SP9TKW]

Doug,

My first RX antenna use d with uBITX v3 was just 20-25feet of wire hanged around room and inserted into center connector. I could receive stations on 80, 40 and 20 bands. I am located in Europe so plenty of stations to listen to .

If you are thinking about POTA/SOTA I would recommend to open their clusters and try to find stations which posted their activation details.

You can also open general cluster and see if you can pick up local traffic. I use https://dxheat.com/dxc/ site and set filter for "de EU" to get stations heard in Europe.

If that works, it means your trUSDX is working fine. Then I would go for a simplest antenna and that is dipole for band which you like. In Europe 40 is a good choice as you can get a lot of local and medium distance traffic. Depending on your location in relation to major cities etc... 20m band might be better choice as a first antenna.

GL 73 Marek