Multi-band HAM antenna for SDR setup - listen only

[crossdw]

I have been using my SDR to listen to trunked systems for a while now, but would like to explore listening to HAM bands as well and looking for some basic info on which kind(s) of antenna I need. Looking for something simple and relatively inexpensive. I have an I.T. and electronics background and am willing to build one if that's easier/less expensive than buying one. I've been reading through posts where these operators are setting up 60' dipoles and such, but at least to start out only listening (not transmitting) is something that elaborate necessary? Is there a good multi-band antenna or do I need a separate antenna for each band?

I'm using a Windows 10 laptop with RTL-SDR v.3 tuners (two for trunking) and using UniTrunker for that, but I also have SDRSharp for listening to other bands.

Thanks

 

[mmckenna]

It would help to know what frequencies/bands you are interested in.

 

[crossdw]

It would help to know what frequencies/bands you are interested in.

Sorry, but I'm completely new to HAM bands so I'm still learning this. I would say the common Amateur-class bands at least to start with until I learn more and figure out what all is there to listen to. In other words, voice comms not CW or other stuff. So I guess to answer your question that would be 10,12,17, 30,60, and 160 meters.

 

[prcguy]

PAR End Fed SWL would be a good start.

 

[mmckenna]

Yeah, an end fed is an easy antenna for that sort of stuff.

Short of band specific dipoles, it's a good all around antenna that is easy to install. I have one connected to a remote receiver and it works well enough for casual listening.

 

[crossdw]

Great! Thanks guys

 

[AC9BX]

For listening to shortwave it's hard to beat a terminated folded dipole. Tilt it from horizontal for more omni-directional reception. Search the TTFD or T2FD, tilted terminated folded dipole. They aren't very efficient antennas but we don't care about that very much for receiving. Build it as big as you can. You get a decent effective bandwidth of about 10 to 1. Build it for 3 MHz and it covers to 30 Mhz. They're quiet and thanks to their impedance are not bothered very much by proximity to other objects. You can tweak the impedance by selection of resistor value. Going for 450 Ohms is good for a 9:1 transformer to feed 50 Ohm coax. You'd hear most all the amateur bands, international broadcast, utilities, etc.

Of course a long piece of wire is pretty good too. An impedance transformer helps to match it to coax and some sort of counterpoise will improve performance dramatically.

 

[prcguy]

A T2FD is most efficient with a 12:1 transformer and a 600 ohm load resistor. I made them with 12:1/600 ohm, 9:1/450 ohm and a 4:1 with various load resistances and the 12:1 combo is noticeably better. Its also a very complicated antenna for a beginner.

For listening to shortwave it's hard to beat a terminated folded dipole. Tilt it from horizontal for more omni-directional reception. Search the TTFD or T2FD, tilted terminated folded dipole. They aren't very efficient antennas but we don't care about that very much for receiving. Build it as big as you can. You get a decent effective bandwidth of about 10 to 1. Build it for 3 MHz and it covers to 30 Mhz. They're quiet and thanks to their impedance are not bothered very much by proximity to other objects. You can tweak the impedance by selection of resistor value. Going for 450 Ohms is good for a 9:1 transformer to feed 50 Ohm coax. You'd hear most all the amateur bands, international broadcast, utilities, etc.

Of course a long piece of wire is pretty good too. An impedance transformer helps to match it to coax and some sort of counterpoise will improve performance dramatically.

 

[AC9BX]

End fed wire is certainly the simplest way to get sufficient signal.

Its also a very complicated antenna for a beginner.

I wouldn't say it's very complicated. It's simple enough to measure. But it can certainly be clumsy and will require some attention in construction to retain shape and stay where it should. It's a lot more complex to build than stringing up a simple wire and requires one to purchase or build a matching transformer.

A higher impedance can improve wideband performance by keeping SWR within 2:1 across the spectrum. Going for 800 Ohms and 16:1 transformer is a good choice. A lower impedance will generally result in less loss. The antenna will lose 20% or much more signal in the resistor. But the lower value can result in swings of impedance across the spectrum exceeding 2:1 so there's more feed line loss. Yep, it'll take some experimenting to get it right for your installation. I find higher values better for me too. Were it not for issues of proximity to other metal I'd use a length of open parallel line but that's not going to work very well here.

 

[W5lz]

For a general coverage antenna, the longest one you can put up would be about as useful as anything you can buy (and a lot cheaper)! There are no 'miracle' antennas, they all receive best on frequencies the antenna's length has a relation with. So, an antenna of 1/2 wave length on the lowest band of interest would be your best bet. The ham bands are more or less harmonically related and that means that while that long thing may be several wave lengths long to a particular band, it'd still be 'better' than an antenna of a harmonically unrelated band.

 

[majoco]

...and it's not "HAM". It's not the initials for anything, it's not a name so it doesn't need a capital. I believe it came from the description of an amateur actor who wasn't very good, a ham actor - and I'm not implying anything, most hams are very good operators!

 

[spongella]

I use a 31 foot vertical with a good radial system since it was already in use for my ham station. Not saying this is the way you should go, it's just an option.

 

[wcsd45]

I am happy with my Ultimax 100, which is end-fed, only 24 ft long, bounded by HOA and best on 40M, 20M. This company makes longer versions, and those are likely a better option. Listen to 40M and 80M bands too.

73,

Chuck KC9QBY

 

[vagrant]

I have used a $13 NooElec Balun One Nine and a 100' of wire with success. For the wire I used $20 18 or 22 gauge wire and just spool/wrap it up as I typically unreel about half of it. I use a short 25' run of LMR-240UF 50 ohm coax to connect the blaun to the receiver, but I have used a short jumper at times too. There are plenty of plans out there to build your own 9:1 balun as well.

 

[jwt873]

For almost a century, ham was used in lower case in publications of the day. Those of us who followed the hobby before the internet became popular, saw the word in lower case when reading magazines like QST, CQ, Amateur Radio, 73 etc. So, seeing it capitalized seems odd.

I'm pretty sure that everyone knows that CB is short for Citizen's Band.. But many have no idea what other letters like MURS, FRS, GMRS, and LMR stand for. They see a bunch of capital letters describing a radio and use them. Ham has three letters and refers to a type of radio, so it must be capitalized too. It got caught up with the real acronyms.

I think the bottom line is that ham has become capitalized and I don't think there's much that can be done to change it.

Out of interest, this link is to a publication from 1921 entitled "The Telegraph Instructor". It's basically a handbook for telegraphers of the era. Dodge: The Telegraph Instructor

In the definitions sections of the publication you'll see two words:

Ham -- (see plug)
Plug -- A telegraph operator who is not proficient.

And, just to keep on topic

For transmitting, length is critical. But for receiving, pretty well any random length wire will work. The longer the better.

I have a 120 foot inverted Vee that I use for transmitting on 80 meters. The peak is 35 feet above the ground. But, It works OK for receiving other frequencies. It's not optimal, but I can hear stations on the other ham bands.

 

[Firekite]

I guess to answer your question that would be 10,12,17, 30,60, and 160 meters.

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