SDR-IQ rx antenna question

[datainmotion]

So, I've decided to take the plunge and buy an SDR-IQ. Being nothing more than a novice SW listener (i.e. - no external antennas) in the past, I have never delved into antennas much. So before I ask the ambiguous "which one is best for me" question, let me give you a few more details:

• I would like an antenna with good rx characteristics from 100 kHz to 30 MHz (I realize comprimises will happen there)
• I own a 2-story house (no HOA or covenants) where the back yard faces west and have an open space behind me
• While a "longwire" isn't an issue spacewise (probably 75'+ between the chimney and shed), I'm not sure I want a wire hanging across the yard
• I would like to spend less than $200 for the whole antenna "package"

Thanks for your help!

Mike

[datainmotion]

I did find the Alpha Delta DX-SWL Sloper and did a little reading up on it - that may be an option...

[nickcarr]

Well - I feel I should just warn you now that shortwave reception is dependent upon several factors. The "antenna" of a SWL station is its bread-and-butter, so to speak. It doesn't matter if you spend $500 or $5000 on a SWL receiver - you're at the mercy of the SW Gods.

As for good starting antennas, here are two:

I don't personally own one of these, but I've heard nothing but great reviews about the Par End-Fed SWL:

Par Electronics EF-SWL End Fed Dipole SWL Antenna. Par EF-SWL.

Just add coax and a BNC adapter and you'll be good to go. This is a wire-based antenna which is probably your cheapest solution.

OR

You could go for something like this: http://www.universal-radio.com/catalog/sw_ant/1026.html

It's a bit more expensive, but it comes with the coax and a BNC adapter - ready to go. Mount that baby as high as possible and it should get you started.

--

Both antennas should work fine but from my experience you'll probably get better results with a wire antenna.

[ka3jjz]

Nick is quite correct; don't shortchange yourself by buying a good receiver and skimp on the antenna. Fortunately building antennas is cheap in comparison; you should be able to do this for well south of USD100; possibly even much less than that if you have a good junkbox.

I would avoid verticals; on HF they're much more sensitive to noise from local sources. The PAR is the right idea; using a transformer plus a coax feed (and getting the antenna as far from the house as you can) is the ticket. PCs can often be an annoying source of noise themselves, so you will need to watch that with any antenna you select. Another nice feature of the PAR is that you can remove the receiving wire and put on a longer strand if you wish; with propagation the way it is, and being on the West Coast, the better the antenna, the better your results will be.

Our wiki has links to numerous antenna articles and manufacturers; and at the bottom, the Shortwave SWL antenna group has tons of different antenna ideas, as well as articles on how to wind your own 9:1 transformer (sometimes also called a magnetic longwire balun, or MLB). To access this, float your mouse over Wiki in the blue toolbar under the logo, then select Antennas then select HF Antennas from the list.

73 Mike

[gcgrotz]

I can vouch for the PAR end fed, after I moved to this house I had to get something going so I stapled the wire loosely along the 42" high wood fence and was able to regularly listen to Radio New Zealand in the mornings here in VA. I later put it down in the back yard with the transformer near the ground and ran the wire up through some tree branches. Used good quality RG8x back to the house, maybe 75' and it got the antenna away from some of the electrical noises in the house. Worked great, I still have it but took it down to put a 43' vertical for transmitting ham bands. I'm gonna try to put the PAR back up on the roof out to a tree in the front so I'll have a second (and horizontal) antenna for RX.

Good luck and have fun!

[k9rzz]

Originally Posted by ka3jjz

Nick is quite correct; don't shortchange yourself by buying a good receiver and skimp on the antenna. Fortunately building antennas is cheap in comparison; you should be able to do this for well south of USD100; possibly even much less than that if you have a good junkbox.


I would avoid verticals; on HF they're much more sensitive to noise from local sources. The PAR is the right idea; using a transformer plus a coax feed (and getting the antenna as far from the house as you can) is the ticket. PCs can often be an annoying source of noise themselves, so you will need to watch that with any antenna you select. Another nice feature of the PAR is that you can remove the receiving wire and put on a longer strand if you wish; with propagation the way it is, and being on the West Coast, the better the antenna, the better your results will be.

Our wiki has links to numerous antenna articles and manufacturers; and at the bottom, the Shortwave SWL antenna group has tons of different antenna ideas, as well as articles on how to wind your own 9:1 transformer (sometimes also called a magnetic longwire balun, or MLB). To access this, float your mouse over Wiki in the blue toolbar under the logo, then select Antennas then select HF Antennas from the list.

73 Mike

However, give the vertical antenna credit for being good at receiving low angle (i.e. often more distant) signals. For example, this past two weeks I've been listening on the 15mhz band to New Zealand, Thailand, and North Korea on my vertical, but those signals are weak and in the noise on my horizontal wire. If you can put up more than one type of antenna (even if it's just two), then you may improve your chances in hearing your target signals.

My .02

[ka3jjz]

No argument there, quite true. However using a PC driven receiver, plus a vertical that may be too close to the house or shack, and guess what the results are likely to be - and the first 2 don't count, hi

73 Mike

[datainmotion]

Originally Posted by nickcarr

As for good starting antennas, here are two:

Par Electronics EF-SWL End Fed Dipole SWL Antenna. Par EF-SWL.

OR

You could go for something like this: Apex Radio 303WA-2 Shortwave antenna. ApexRadio

Both antennas should work fine but from my experience you'll probably get better results with a wire antenna.

I think you just found a great antenna for the SDR-IQ when I'm travelling (i.e. - camping) with the Par. Thank you!

I saw the Apex looking at Universal's site this weekend, but opted against it due to its height, but thank you for suggesting it!

Thanks,

Mike

[datainmotion]

Originally Posted by ka3jjz

Our wiki has links to numerous antenna articles and manufacturers; and at the bottom, the Shortwave SWL antenna group has tons of different antenna ideas, as well as articles on how to wind your own 9:1 transformer (sometimes also called a magnetic longwire balun, or MLB). To access this, float your mouse over Wiki in the blue toolbar under the logo, then select Antennas then select HF Antennas from the list.

73 Mike

I did "float" through the wiki this weekend and it does have quite a bit of useful info on antennas, which by the way, is how I came up with the Alpha-Delta sloper.

Funny side-note on that is how many calls I had to make to family members and friends to find one who remembered Pythagoras Therorem (to figure out the distance between the top of the chimney and the peak of the shed). Most answers were "Google it" which yes would be simpler, but not nearly as entertaining...

[electricman]

FWIW, the Alpha Delta DX-Ultra and DX-SWL Sloper according to Passport to World Band Radio is rated #1 and #2.

[datainmotion]

Thanks for the ratings info.

While I realize I did start by saying I wasn't "sure that I wanted a wire hanging across the yard", the Par and Alpha-Delta both look very good to me right now...

[nickcarr]

Originally Posted by electricman

FWIW, the Alpha Delta DX-Ultra and DX-SWL Sloper according to Passport to World Band Radio is rated #1 and #2.

Just note that what works for someone else may not work for you. Again, we're talking about several factors that come in to play here: location, elevation, noise sources, atmosphere, climate, soil conductivity, noise sources, location... oh, and did I mention location?

My point is not to read too much into the "commerical" wire antenna systems. You can spot commerical antennas because they generally cost $100 or more.

IMO - Moving the "system" (i.e. balun and antenna lead) away from the house is the most drastic and noticeable improvement to a shortwave listening post. Using quality (i.e. not cheap) coax is almost always another good bet.

[gcgrotz]

Mike, Mike, and all the others:

Well, you have to take the bad with the good. I live in the city so I have no HOA restrictions but my lot is only 30x120 and most of the 120 is taken up by the front yard and the house. And no real trees to hang a good dipole, plus it would have been right over the house. Vertical was the only way to go. At least it is 25-30 feet from the house, and I was able to put over 70 radials down (1000+ feet of wire). There is a small wood toolshed in the back and the antenna is mounted on the side with some insulated brackets. I'm using a home brew 43 foot vertical with an unun, and can switch to the remote tuner. I'm VERY happy with its performance on 40 meters, and not bad on 75. I can't really tell about 20 meters because the bands have been so bad.


Anyway, just have fun and put up the best thing you can!

[kb2vxa]

There are many antenna designs for every purpose but in the case of the average SWL orientation is a factor often overlooked. When it comes to wave polarization, as the signal propagates off the ionosphere polarization becomes scrambled from moment to moment so a combination of vertical and horizontal antenna elements is often desirable to minimize fading. (Selective fading is another matter and another discussion.)

I have had excellent results with the common inverted L fed at the ground or very near to it which BTW makes lightning surge protection and signal grounding the coax (9:1 un-un or tuner needed here for best performance) simple and most effective. There is another type I haven't tried but hear it's pretty good, a dipole or off center fed dipole with the apex elevated and one element vertical going down and the other horizontal. Then there is the good old reliable inverted V, but I better stop here or I'll end up writing another book.

One last thought, nobody ever said everything must be run in straight lines, just don't run wires right next to each other.

[datainmotion]

First off let me say thank you to all for your input and advice!

I went with the 60' Alpha Delta Sloper for a couple reasons including the wideband performance, ease of installation (the wife and I had it up and running in less than an hour, from the chimney to the shed) and it won't cause the "What is that??" questions from the neighbors. The wire crossing the back yard isn't really noticeable unless you look up.

Without sounding a like a kid at Christmas, I'm still giddy about the ability to get back into SWL again and this time with more than a DX390 and a speakerwire antenna though I am still a novice.

Unfortunately, slipping away to actually listen as much as I'd like might be a bit more difficult...

Again thank you all for taking the time to reply.

P.S. - for those of you wondering about the coax, I used an RG-8X that I already had up on the chimney for a back-up scanner antenna.

[kb2vxa]

"The wire crossing the back yard isn't really noticeable unless you look up."
So why am I laughing so hard I can hardly breathe? If anyone should ask tell them it's an old Polish charm for driving away evil spirits, a slide for birds, an energy collector for green power... ANYTHING but an antenna!

Oh you're welcome, enjoy collecting radio waves and putting them in your ears, better than beans. YouTube - Len Chandler - Beans in my Ears

[datainmotion]

Always happy to make you laugh Warren. Actually I'll tell them its a rainfall collector made from the skin of baby seals.

But seriously, a grey 14ga wire 15 ft over the deck in a yard full of mature Ponderosas doesn't stick out even when you do look up. much.

[prcguy]

A vertical will be much noisier as others have mentioned regardless of the amount of radials. Just this last weekend I installed for a friend, a 26ft long Butternut 6 band HF vertical in the middle of a 100ft X 100ft roof that was solid bonded copper sheet metal, can't get much better than that for a ground plane. I also installed a double size G5RV 204ft flat top dipole at 30ft next to the building.

The antennas are connected to a remote HF transceiver and so far both antennas have about the same transmit and receive levels but the dipole is noticeably quieter on all bands.

I have never had any end fed SW antenna, tuned or otherwise or any dipole fed with coax work as well on multiple bands as a simple center fed dipole, as large as you can fit on you property and fed with balanced feedline right to the receiver (or transceiver with a tuner).

Forget the baluns, never mind the twinlead to receiver mismatch and just put up a simple center fed dipole with balanced line. Total cost might be $20 and you'll never look back.
prcguy