Question about antennas in General

comoman · Nov 16, 2014

I have a Grundig Satellit 750 shortwave receiver. I have a 45 feet long Par Electronics EF-SWL end-fed antenna horizontal about 25 feet high. This antenna is supposed to be good for 1-30 MHz.

My question is, does the same thing apply to shortwave antennas as other antennas when it come to being horizontally verses vertically polarized? Is this antenna considered directional in the horizontal position? If so why is it directional horizontally but not vertical?

I do not get very good reception with this antenna and I'm trying to figure out what I need to do. I've got lots of space outside. I just don't know if I need to re-locate this antenna or buy a different antenna.

ka3jjz · Nov 16, 2014

Horizontal mounting is preferred, but from the diagrams I have seen this antenna could be mounted at an angle (making a sort of sloper) which would have some directivity in the direction of the slope on some frequencies.

This antenna is a fine performer for a start, but with the 750, there's a couple of things you need to do. This is ignoring the possibility of a crummy coax connection (always a possibility)

First make sure that the antenna switch on the right of the set is in the EXT ANT position.

Next make sure that your RF Gain control on the right is about 75% or so to the right. You may need to back it off some if you find overloading to be a problem. The telltale sign of this would be having stations (say from MW or even other HF stations) showing up where they don't belong (say in the 8 Mhz area).

Next you need to experiment with the transformer connections. There are several possibilities here, and only experience is going to show you which one works best in your location.

Are you grounding the transformer? If so, how? Just ramming a rod into the ground is not really the best for getting a good RF ground, although you'll find many manuals that will tell you otherwise. Your situation may in fact improve if you don't ground the transformer at all.

You can also try something borrowed from the ham community - take a couple of pieces of wire and cut them to make radials, which you would attach to the black ground connector. Cut them for the lowest and highest frequencies you want to hear. The formula is quite simple - 234 / f(Mhz) where f(Mhz) is the frequency in Mhz. No need to get fancy - just throw them behind the desk or bookcase in opposing directions. They don't even have to be fully extended - just don't let the 2 touch or get close to one another (they will interact if this happens)

Be more specific about not getting 'very good reception' - where and when are you listening? HF is not like scanning - as we approach the winter season (although some will tell you - and it feels like - we're already there...) the lower frequencies (below 10 Mhz) will in fact improve. Listen below 10 Mhz at night, above this during the day. In general the highest freqs broadcasters will use during the day would be 16 (around 17600 to 17900 Khz) and 13 meters (21450 to 21850 Khz - there won't be much activity on 13 meters to North America, for the reasons just mentioned...). The 19 meter band (15100-15450 Khz) is a good top band to use.

By the way Dale Parfitt (the owner of PAR Electronics, the original manufacturer of these antennas) is quite famous for helping folks out with installation questions. I wouldn't hesitate dropping him an email if you still can't figure out what's going on here (and I believe he's a RR member).

Mike

comoman · Nov 17, 2014

ka3jjz said:
Horizontal mounting is preferred, but from the diagrams I have seen this antenna could be mounted at an angle (making a sort of sloper) which would have some directivity in the direction of the slope on some frequencies.

This antenna is a fine performer for a start, but with the 750, there's a couple of things you need to do. This is ignoring the possibility of a crummy coax connection (always a possibility)

First make sure that the antenna switch on the right of the set is in the EXT ANT position.

Next make sure that your RF Gain control on the right is about 75% or so to the right. You may need to back it off some if you find overloading to be a problem. The telltale sign of this would be having stations (say from MW or even other HF stations) showing up where they don't belong (say in the 8 Mhz area).

Next you need to experiment with the transformer connections. There are several possibilities here, and only experience is going to show you which one works best in your location.

Are you grounding the transformer? If so, how? Just ramming a rod into the ground is not really the best for getting a good RF ground, although you'll find many manuals that will tell you otherwise. Your situation may in fact improve if you don't ground the transformer at all.

You can also try something borrowed from the ham community - take a couple of pieces of wire and cut them to make radials, which you would attach to the black ground connector. Cut them for the lowest and highest frequencies you want to hear. The formula is quite simple - 234 / f(Mhz) where f(Mhz) is the frequency in Mhz. No need to get fancy - just throw them behind the desk or bookcase in opposing directions. They don't even have to be fully extended - just don't let the 2 touch or get close to one another (they will interact if this happens)

Be more specific about not getting 'very good reception' - where and when are you listening? HF is not like scanning - as we approach the winter season (although some will tell you - and it feels like - we're already there...) the lower frequencies (below 10 Mhz) will in fact improve. Listen below 10 Mhz at night, above this during the day. In general the highest freqs broadcasters will use during the day would be 16 (around 17600 to 17900 Khz) and 13 meters (21450 to 21850 Khz - there won't be much activity on 13 meters to North America, for the reasons just mentioned...). The 19 meter band (15100-15450 Khz) is a good top band to use.

By the way Dale Parfitt (the owner of PAR Electronics, the original manufacturer of these antennas) is quite famous for helping folks out with installation questions. I wouldn't hesitate dropping him an email if you still can't figure out what's going on here (and I believe he's a RR member).

Mike

I've got the external antenna switch in the correct position.

I'm not sure about the RF Gain control since it doesn't appear to make a lot of difference where it's set on some signals while on SW.

I don't understand what you mean by the "transformer connections." There is only one ground terminal on the Grundig 750 receiver and it is next to the Red 500 ohm wire antenna connection on the right side. The ground terminal is grounded through an MFJ Versa Tuner II antenna tuner to an 8' ground rod that I have all of my radio equipment grounds through.

As far as poor reception. There are some audible signals that are very low that makes no difference how it's tuned. I've tried all of the antenna tuner inductor selector positions, tuned the antenna and can't get more than 1 to 2 dB reception. It may be that the signal origin is just to far away or the location and the position of my antenna isn't right for decent reception. I get pretty good reception on 41 Meters and not so good reception on 25 meters but I get decent reception on 10 Meters.. I get a few signals that sound like SSB but can't find them on LSB or USB. The amateur radio operators are the ones that I am most interested in listening to.

Thanks for the input about Dale Parfitt . I could probably make good use of some help from him.

Thanks or all of the explanation and information.

SCPD · Nov 17, 2014

Something doesn't sound right in your connections. Let's back up a bit.

Dump the tuner. You don't need a tuner here.

Connect with coax (at least RG-8x or better) from the PAR transformer's SO-239 jack to the BNC jack of the 750 (you may need to buy an SO-239 to BNC adapter.)

Set the Antenna switch to EXTERNAL

Set SQUELCH to full counter-clock position (so you hear static)

Set RF GAIN to MAX.

Tune to WWV on AM. You can try 20 Mhz, 15 Mhz, 10 Mhz, 5 Mhz depending on time of day.

If you hear WWV well then go find your SSB signals. Remember to be in USB mode for > 10 Mhz and LSB for < 10 Mhz.

Adjust the BFO dial to "fine tune" the SSB signal. (Unfortunately, a lot of HAMs don't know that their radios are off-frequency and so you'll need to compensate for that by using the BFO.)

PS. Here's a decent image of how it should look:

You can put the PAR transformer at ground level to make your coax distance short but either way, it needs to be outside. Ideally, as far away from the house as possible. The primary antenna wire and the PAR transformer should be outside and away from any metal structures.

You mentioned that you have a ground rod. You can connect the ground rod to the "ground lug" on the PAR transformer. I believe this is marked or shown in the documentation. Do this *only* if you plan to mount the transformer close to ground. That ground lead should be thick gauge copper wire (4ga or larger) but most importantly it must be short in length.

For now, I wouldn't worry about grounding the transformer. So in the above image, I would put the PAR transformer at the center roof of the house. Run the coax down the side of the house into your 750.

Keep the primary antenna wire flat (parallel to the actual ground surface.) This is horizontal polarization and works best for HF. Vertical polarization works but it can be more noisy.

Again, get the antenna far from the house and use coax as your lead into the 750. You can experiment with grounding it later.

Height is also important but not as important as getting it away from your house.

comoman · Nov 17, 2014

nickcarr said:
Something doesn't sound right in your connections. Let's back up a bit.

Dump the tuner. You don't need a tuner here.

Connect with coax (at least RG-8x or better) from the PAR transformer's SO-239 jack to the BNC jack of the 750 (you may need to buy an SO-239 to BNC adapter.)

Set the Antenna switch to EXTERNAL

Set SQUELCH to full counter-clock position (so you hear static)

Set RF GAIN to MAX.

Tune to WWV on AM. You can try 20 Mhz, 15 Mhz, 10 Mhz, 5 Mhz depending on time of day.

If you hear WWV well then go find your SSB signals. Remember to be in USB mode for > 10 Mhz and LSB for < 10 Mhz.

Adjust the BFO dial to "fine tune" the SSB signal. (Unfortunately, a lot of HAMs don't know that their radios are off-frequency and so you'll need to compensate for that by using the BFO.)

PS. Here's a decent image of how it should look:

You can put the PAR transformer at ground level to make your coax distance short but either way, it needs to be outside. Ideally, as far away from the house as possible. The primary antenna wire and the PAR transformer should be outside and away from any metal structures.

You mentioned that you have a ground rod. You can connect the ground rod to the "ground lug" on the PAR transformer. I believe this is marked or shown in the documentation. Do this *only* if you plan to mount the transformer close to ground. That ground lead should be thick gauge copper wire (4ga or larger) but most importantly it must be short in length.

For now, I wouldn't worry about grounding the transformer. So in the above image, I would put the PAR transformer at the center roof of the house. Run the coax down the side of the house into your 750.

Keep the primary antenna wire flat (parallel to the actual ground surface.) This is horizontal polarization and works best for HF. Vertical polarization works but it can be more noisy.

Again, get the antenna far from the house and use coax as your lead into the 750. You can experiment with grounding it later.

Height is also important but not as important as getting it away from your house.

With the antenna tuner I get +60dB on WWV at 5 Mhz. At 20 and 10 Mhz I get no signal at all. Without the tuner I receive about +15 dB.

I don't remember if I connected a ground lead to the transformer or not. I'll have to look at it when it daylight. The feed point where the RG-8 coax is connected is 30' feet from the ground.

mancow · Nov 17, 2014

I'm getting nothing on 10 and 20 MHz right now either. That's normal for night time. The fact you are getting 5 MHz at +60 db means your antenna is likely working fine. Try again in the day time and your higher frequencies will come in better.

SCPD · Nov 17, 2014

I also hope you understand that SSB signals are *much* weaker than AM Broadcast signals. Some HAMs are lucky enough to run with 600w or more and they sound like a broadcast station. Most SSB signals are 100w or less.

SSB signals are much harder to find (non-HAM) and are far more susceptible to propagation conditions.

BTW, just in case you're not aware, SW Broadcast stations are usually upwards of 250,000w of power.

ka3jjz · Nov 17, 2014

nickcarr said:
I <snip>
BTW, just in case you're not aware, SW Broadcast stations are usually upwards of 250,000w of power.

You wish. There are many broadcasters that use 1 KW or less. Try working the 60-90 meter bands and avoid the religious garbage. You'll find many stations like that (heck, even CHU and WWV don't run that much power). Oh and the rule about using LSB below 10 Mhz and USB above only applies to hams. You'll find many utility stations that break that so-called 'rule'. But I digress....

Anyhow, if you're getting +15-+20 / S9 your antenna is working fine. As Nick suggests, putting the transformer side of the antenna close to the ground makes it easy to fiddle with the connections there. Find a combo that works in your environment. It will take some experimentation, but you'll learn more that way..

Don't go for just signal strength. Learn to think in terms of the quality, not the quantity, of the signal. I'd much rather hear a station that was S9 and no noise or interference than a station at 20 over 9 with a lot of slop any day. Mike

comoman · Nov 17, 2014

ka3jjz said:
You wish. There are many broadcasters that use 1 KW or less. Try working the 60-90 meter bands and avoid the religious garbage. You'll find many stations like that (heck, even CHU and WWV don't run that much power). Oh and the rule about using LSB below 10 Mhz and USB above only applies to hams. You'll find many utility stations that break that so-called 'rule'. But I digress....

Anyhow, if you're getting +15-+20 / S9 your antenna is working fine. As Nick suggests, putting the transformer side of the antenna close to the ground makes it easy to fiddle with the connections there. Find a combo that works in your environment. It will take some experimentation, but you'll learn more that way..

Don't go for just signal strength. Learn to think in terms of the quality, not the quantity, of the signal. I'd much rather hear a station that was S9 and no noise or interference than a station at 20 over 9 with a lot of slop any day. Mike

Fortunately I have an antenna mast that lays down fairly easily and quickly if I need to. I can have it down and back up in less than 5 minutes. A welder buddy made it. I'll have to take a picture one of these day and show it to you. guys.

About the SW receiver. I really wasn't sure what I to expect from the Grundig 750. So I guess it must be working ok.

I appreciate all of the input from you guys.

ka3jjz · Nov 17, 2014

I'd be a bit leery if that transformer is too close to the mast (I assume it's metal). Too close and the transformer might interact with that mast in ways that are difficult to predict. Get it away from that mast as much as possible

Mike

comoman · Nov 17, 2014

ridgescan · Nov 17, 2014

First, nice antennas

next, I'd like to add to the previous wisdom by Mike and Nick my personal experiences with the PAR.
I ran the PAR mounted on top of a 10' steel mast. I ran 100' of #12 solid copper wire off it. I found in my environment, that shorting the two ground lugs together on the PAR transformer (the transformer that Mike was referring to) and then grounding them to the steel frame of my building via the fire escape worked to eliminate a ton of noise, and I enjoyed some pretty great long distance stuff with that setup-even in daytime.
From what I see in your pic,do you have the far end of the PAR wire element pointing very close to the pole of that discone or is that the feedpoint-correct me if I am wrong. But that pole, if metal, along with the discone and its feed, may have an effect upon the PAR's reception quality if that was the far end. I personally would prefer having that PAR wire element's far end terminating to something non metal like a wood dowel pole or something, but having the PAR transformer box feedpoint at the pole was ok with mine. Anyways, experimenting with different setups is kind of necessary to obtain the best one.

comoman · Nov 17, 2014

ridgescan said:
First, nice antennas next, I'd like to add to the previous wisdom by Mike and Nick my personal experiences with the PAR.
I ran the PAR mounted on top of a 10' steel mast. I ran 100' of #12 solid copper wire off it. I found in my environment, that shorting the two ground lugs together on the PAR transformer (the transformer that Mike was referring to) and then grounding them to the steel frame of my building via the fire escape worked to eliminate a ton of noise, and I enjoyed some pretty great long distance stuff with that setup-even in daytime.
From what I see in your pic,do you have the far end of the PAR wire element pointing very close to the pole of that discone or is that the feedpoint-correct me if I am wrong. But that pole, if metal, along with the discone and its feed, may have an effect upon the PAR's reception quality if that was the far end. I personally would prefer having that PAR wire element's far end terminating to something non metal like a wood dowel pole or something, but having the PAR transformer box feedpoint at the pole was ok with mine. Anyways, experimenting with different setups is kind of necessary to obtain the best one.

The view is of the feed line connection. That's a SIRIO 2000 antenna above it. The feed point of the PAR wire antenna and the fastening device is insulated from the metal mast. Are you talking about the PAR antenna being in the proximity of the metal mast and SIRIO 2000 antenna affecting the reception even though it insulated? I haven't thought of that. How long of an insulating support line would you recommend for this setup to get it away from the metal mast?

ka3jjz · Nov 17, 2014

Just to be clear - the transformer that I refer to is on the extreme left of the pic in the original post, and is also found on page 2 of...

http://www.lnrprecision.com/manual/EF-SWL.pdf

(it's a PDF file)

See instruction 1B that talks about having to experiment with different connections to this transformer

I would keep 4-5 foot away from any metallic objects like masts....Mike

comoman · Nov 17, 2014

ka3jjz said:
Just to be clear - the transformer that I refer to is on the extreme left of the pic in the original post, and is also found on page 2 of...

http://www.lnrprecision.com/manual/EF-SWL.pdf

(it's a PDF file)

See instruction 1B that talks about having to experiment with different connections to this transformer

I would keep 4-5 foot away from any metallic objects like masts....Mike

Yes that is correct. I thought it was called a Balun.

ka3jjz · Nov 17, 2014

Baluns are transformers - even in the documentation (which you should read), you're going to see that little grey box referred to as such.

Actually the word 'balun' is a contraction - it takes a balance load to an unbalanced one. Anything that transforms in this manner can be generally thought of as a 'transformer'. An example of a common usage would be a transformer that changes AC to DC...which you will find in many desktop radios. The electrical principles are not that different.

Now for a bit of explanation - when a voltage - even a small RF one - is passed through a transformer, it creates an EM field around it. If there is any metallic object nearby, it may interact with it. In this case we want to avoid that, because it is possible that the antenna could be detuned, resulting in a weaker signal than you would normally get. Therefore, you want to keep that transformer away from metal objects as much as possible.

You will also see in that documentation what I had said earlier - that experimenting with the connections is going to be the way you determine what works best in your particular environment. You might even take that 45 foot of wire and substitute it with something longer, if you have the space to do it. However, don't go too long - or you will at some point overload the 750. You will know this is happening when you start hearing MW or other HF stations in places they don't belong (like, say on the 8 Mhz or 10 Mhz bands).

And keep in mind what I said earlier about where to tune - 10 Mhz and below at night, above this (up to about 18 Mhz or so for broadcasters) during the day. At night the higher bands (above 10 Mhz) will collapse - although the 25 meter band (11600-12000 Khz or so) will often stay open for a couple of hours after local sunset. But it too will close down shortly thereafter.

Mike

nanZor · Nov 18, 2014

comoman said:
My question is, does the same thing apply to shortwave antennas as other antennas when it come to being horizontally verses vertically polarized? Is this antenna considered directional in the horizontal position? If so why is it directional horizontally but not vertical?

For HF signals bouncing off the ionosphere, it no longer really has a polarity on the receive side. However, antenna mounting and height will have an OVERALL directional component to it, having better angles of reception than others depending on how you mount it. Around town with a direct line of sight, you'd be more or less horizontal - but ...

As you've described it sounds like your PAR is mostly horizontal. Yet, the common-mode of your coax (outer skin of the braid) coming down is ALSO part of the antenna at this point making it act like an inverted L, and not just a horizontal wire (forget polarity - we're just talking ionospheric reception angles).

What I'd recommend is using a 1:1 RF choke, such as an MFJ 915 up near the PAR transformer. Like off just a little 1 foot jumper. This will also help with common-mode noise INGRESS coming from the shack, up to the antenna, and back down again. Essentially this is trying to make only the 45 foot part of your antenna the sole reception element.

The PAR antenna is quite configurable, where you can play around with the grounding so that you can have radials if you like (if the par transformer was near the ground), or open, so that you can use counterpoise wires at the back of the rig.

OR, you can invest in a 1:1 rf choke balun like the MFJ 915, and put it up near the feedpoint. Also note that you are not stuck with using the PAR wire - you can use your own and cut and prune to taste. For instance, when modeled with EZnec, that 45 foot radiator up at 25 feet has an ok angle of about 25 degrees to it near 20mhz, BUT about -12 to -17 dbi attenuation from 19.5 to 20.5 mhz. If that frequency range is REALLY important to you, you may want to prune or add 6 inches to the wire, and try again.

The Grundig is also not the worlds best when it comes to strong signal handling. With a large antenna like that, it would not be uncommon to have to use BOTH the built-in fixed attenuators, along with the adjustable rf-gain. I know I had to with mine until it just became too frustrating.

SCPD · Nov 18, 2014

comoman said:
The view is of the feed line connection. That's a SIRIO 2000 antenna above it. The feed point of the PAR wire antenna and the fastening device is insulated from the metal mast. Are you talking about the PAR antenna being in the proximity of the metal mast and SIRIO 2000 antenna affecting the reception even though it insulated? I haven't thought of that. How long of an insulating support line would you recommend for this setup to get it away from the metal mast?

I just looked up the other antenna as I'm not a CB'er but yes, since you're transmitting with that antenna (I'm presuming) then you want to completely separate both antennas. Ideally, I would put the SIRIO up on the roof and then you could leave the PAR alone. If you'd rather move the PAR then that's fine too but get them completely away from each other.

One other point to mention is that since your wire is horizontal the receive side is broadside to the wire. So, think of a doughnut with the antenna wire going through the center. So, the point to consider is where you are located. If you're located on the east coast, then you'll probably want your antenna oriented N-S. This means you'll receive better on the E-W. If you were in Seattle then you would probably want it to aim NE-SW to get that SE direction toward the USA.

The logic all depends on what you're seeking to hear. You may be limited to its direction so don't fret too much over which way it goes. This can be the fun part of shortwave -- experimenting with different antenna configurations.

Question about antennas in General

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