Question methods of lowering SWR

[The DB]

Just read your "Finally....conditions" post. It seems your setup is working fine. I'm wondering if your wife is doing something that is killing her receive of your signal. I would check her Squelch and see how high it is set and perhaps her RF Gain if she has one.


The DB

 

[roadrage]

Just read your "Finally....conditions" post. It seems your setup is working fine. I'm wondering if your wife is doing something that is killing her receive of your signal. I would check her Squelch and see how high it is set and perhaps her RF Gain if she has one.


The DB

I had her adjust the squelch til she heard static. I'll check the Rf gain on her radio. Could it be that the take off angle is different on the 1/4 wave and its, for lack of a better term, shooting right over her?

Yeah, on the Dx things seemed fine today. I had better performance across the country than down the road, lol. When I do get a response, they tell me my signal is pretty strong (I've had many 7s and up on their meter)and my audio is reported as loud and clear. I am not really seeing a big improvement over the Wilson 1K that the 102" replaced. I'm not saying that its performing horribly as a whole. It should just be performing better. There is something that needs attention. Maybe the coax I'm using is too old, maybe I have to remove that shunt coil. Maybe both. I have an idea about running the coax from radio to near the antenna then a barrel connector, to a short coax with the terminal connectors to the antenna. That way i can place a meter close to the feed of the antenna if I need. I also have a plan to cut the head liner and put a small plastic access panel. That way I don't have to keep ripping down my headliner and ruining it.

 

[W5LZ]

I think things are about as 'good' as they will get. There doesn't appear to be anything wrong with your setup, it just doesn't meet your expectations.

Antenna analyzers and SWR meters, they are NOT the same things at all, they measure different things. Both are just indicators, you have to know what those indications mean and how to understand/fix/correct/interpret them. It is not intuitive.
An SWR meter can't tell you anything about an antenna's resonance, it can't measure what you need to know to determine resonance. An SWR meter can't tell you much about impedance matching either. There are a huge number of not even close impedances that can make it think the SWR is 1:1 when it isn't. SWR meters are very over-rated and misunderstood.
What about that impedance matching coil on your antenna, is it 'robbing' you of performance? No, it isn't, and there's an easy way of finding out. Just remove it and compare the results. (Don't destroy it, you'll wanna put it back.) Don't expect a "day light/dark" difference in performance, there won't be one. There will definitely be a difference though.
There are always two parts to communications between two points. Optimizing one of those 'parts' is only half the problem. The other 'part' has to be considered too. [If SHE says NO, then I am NOT saying you should 'fix' HER side of it! I'm silly, but I ain't that stupid (and I don't think you are either!). It's your 'neck'.]
Having said all that, here's the 'disclaimer', or 'CYA'. We can only go by what you tell us about the situation. There are all kinds of things that could be -the- 'problem' that makes it less than what it should be. That doesn't mean you are at fault in any way, just that nothing replaces a 'hands on' as opposed to a 'telling about it' thingy, you know?
Good luck.
- 'Doc

 

[Shockwave]

Probably just an MFJ 259 or something similar. It may not be the most accurate thing but right now I have a $20 SWR meter that just aint doing it. If I had only had a 4W radio with a tune and a mag mount, that SWR meter would be fine. I am getting in over my head with not enough equipment. Sucks that this hobby costs so much money to do it right. Seems like every upgrade needs 3 other upgrades to keep it all together. With my radio that swings up to 150W and a 102" antenna, I can't even out talk my ears when talking to my wife. And she is running my old Galaxy 929 (18W peak) and a K30. I can hear her before she hears me. Last night we did a radio check at about 9 miles. She could tell I was talking but couldn't understand me at all. She was coming in with some static but very readable. Something ain't right.

There is the possibility that your Wife's radio is receiving electrical interference from the vehicle that is reducing her ability to hear. Try the same range test again with her turning the engine off to see if it improves things. Taking note of the noise level on the receive meter to see if anything is competing with your signal.

 

[roadrage]

I think things are about as 'good' as they will get. There doesn't appear to be anything wrong with your setup, it just doesn't meet your expectations.

Antenna analyzers and SWR meters, they are NOT the same things at all, they measure different things. Both are just indicators, you have to know what those indications mean and how to understand/fix/correct/interpret them. It is not intuitive.
An SWR meter can't tell you anything about an antenna's resonance, it can't measure what you need to know to determine resonance. An SWR meter can't tell you much about impedance matching either. There are a huge number of not even close impedances that can make it think the SWR is 1:1 when it isn't. SWR meters are very over-rated and misunderstood.

- 'Doc

I realize that, but it is good practice to keep a meter inline for reference. When the amp gets back I need to monitor my power levels. Plus a change in SWR will alert me if something goes south before I end up with more repair bills.

IF I can sell my guitar amp and guitar, I'll buy an analyzer. My wife OKed the idea. I can use it to see what my sysem is doing. If there is something that can be improved, I'll see it and be able to fix it. Then I'll put the SWR/power meter inline to keep an eye on things from there.

 

[HomerBB]

I agree with the direction folks are sending you with respect to the differences in the receive of the two radios.

RF gain aside, some radios just have better receive than others. Swap the radios out to the other automobiles and then see if the receive advantage shifts from your truck to her car.

As for capacitors, it is possible to fashion them from a whole host of materials.
Here is an example of a home brewed two plate capacitor:

Two pieces of aluminum bar stock, and a nonconducting insulator between them. Screws and nuts are at each end for wiring it up.

 

[roadrage]

I agree with the direction folks are sending you with respect to the differences in the receive of the two radios.

RF gain aside, some radios just have better receive than others. Swap the radios out to the other automobiles and then see if the receive advantage shifts from your truck to her car.

As for capacitors, it is possible to fashion them from a whole host of materials.
Here is an example of a home brewed two plate capacitor:

Two pieces of aluminum bar stock, and a nonconducting insulator between them. Screws and nuts are at each end for wiring it up.

I know both radios pretty well. The Galaxy 929 in her car was in my truck for a few years and the receiver was good. In fact, when the 929 was in my truck and she had a Midland 1001z, it was the same. I could hear her before she could hear me. Maybe somethng in her car does affect the receive and not the transmit? Is that a possibility? It seems like what would affect one, would also affect the other. But I don't know.

I really can't swap radios The 95t has a different power wire than the standard 3 pin. I could easily put the 929 in my truck with a power plug for the cigarette lighter (temporary purpose only). But it wouldn't be that easy to re-route powr cables for the big radio in her car. She definately wouldn't let me start drilling through her firewall.

edit: Last night I could hear faint DX stations on ch 17. Not enough to move the meter much, but I could hear them. I went to her car and heard them as well as on my truck's radio. I went to my fishing truck (with a Uniden Grant and dual fiberglass antennas) and heard it better than both the other radios. they all were parked no more than 10 Ft from each other, in the driveway.

 

[HomerBB]

Antennas can make a difference.
The duals might have helped, although I'd not put any hard earned cash on a bet, and if you won't tell anyone I have had some of the best mobile DX experiences with a simple 4' top-loaded Wilson fiberglass antenna, and that more consistently than with either 102" whips, bottom loads, or mid-loaded antennas . . .
Sometimes it's the location antennas are mounted on the vehicle, relationship to the earth in terms of distance between the antenna and the ground, and or quality of the entire antenna system.

Cheaper coax can crimp your style where an antenna is concerned. I have measured as much as a 45% power loss through Radio Shack coax on a 100' piece. And I've had terrible matching issues with Radio Shack coax in my mobile that was cured by putting in a better quality coax.

 

[roadrage]

Antennas can make a difference.
The duals might have helped, although I'd not put any hard earned cash on a bet, and if you won't tell anyone I have had some of the best mobile DX experiences with a simple 4' top-loaded Wilson fiberglass antenna, and that more consistently than with either 102" whips, bottom loads, or mid-loaded antennas . . .
Sometimes it's the location antennas are mounted on the vehicle, relationship to the earth in terms of distance between the antenna and the ground, and or quality of the entire antenna system.

Cheaper coax can crimp your style where an antenna is concerned. I have measured as much as a 45% power loss through Radio Shack coax on a 100' piece. And I've had terrible matching issues with Radio Shack coax in my mobile that was cured by putting in a better quality coax.

The coax is jumping out at me as the possilble weak link. It is older coax so it won't hurt to replace it. I hope to get some newcable soon. I have been looking at some LMR400 knock off that sells for .59 a ft. I can buy enough for my base set up and my mobile. Either that or I'll use RG8X for the mobile. I have to make some jumpers wth it too. I have more ground strapping on my watchlist too. I just can't pull the trigger yet.

I went with the 102" because when I bonded my truck it raised my SWR. With low power it wasn't noticable, but was SWR was higher than I wanted it with my power up. I didn't realize, at the time, that bonding my truck caused a mismatch that could have been corrected by tuning the loading coil of the Wilson. And the resonant frequency hadn't changed as the physical length was the same. I am not taking down the 102" now, to mess with the Wilson. I am selling some stuff to buy an analyzer so I'm not flying blind.

 

[W5LZ]

"...LMR400 knock off that sells for .59 a ft."
I can certainly understand wanting to be frugal but that 'knock off' part may turn things into 'expensive' instead. You might want to think about that a bit, at least do some factual comparing between that 'knock off' and the real thing.
Depending on the length of the run, the benefit of LMR-400 at HF just isn't all that great. As for jumpers, that stuff is really stiff and isn't exactly the best choice. As in, are your radios and other devices heavy enough to 'tame' that stiffness?
- 'Doc

 

[Mudfoot]

You can get flexible stranded LMR400.

But as said. Stay away from clone cable. If it says Times Microwave, then get it.

Cheap coax isn't good. Good coax isn't cheap.

 

[KM3F]

I got a chuckle out of the thought the 1/4 wave whip should have been better than the Wilson base loaded antenna.
Here is another example where intuitive thinking fails in the shadow of theroy.
The received signal induced into the element is vertually the same level in both antennas, so why would it be expected a difference could be heard?
In the radio world, a 3 db difference is about the least that can be distingished by normal displays and human hearing.
Related to power, that's a 1/2 power change.
Changeing antennas will never show up that much change in ability to intercept a signal assuming the signal is the same strength.
The only way to see smaller changes is with insturmention set up to make those low level measurements.
Additionally, here is something to think about.
A 1/4 wave antenna matched down has a certain intercept sensitivity.
A base coil loaded antenna's only electrical difference is a narrower band width from some additional Q.
Besides being a bit shorter, the Q increase makes up in great measure for the shorter physical length in signal strength at the receiver.
It's sensitivity is vertaully the same in the application.
Bottom line is not to get mixed up thinking physical size should make a big difference in this application.
It's again, the electrical properties that are the important items.
Good luck.

 

[Shockwave]

I got a chuckle out of the thought the 1/4 wave whip should have been better than the Wilson base loaded antenna.
Here is another example where intuitive thinking fails in the shadow of theroy.
The received signal induced into the element is vertually the same level in both antennas, so why would it be expected a difference could be heard?
In the radio world, a 3 db difference is about the least that can be distingished by normal displays and human hearing.
Related to power, that's a 1/2 power change.
Changeing antennas will never show up that much change in ability to intercept a signal assuming the signal is the same strength.
The only way to see smaller changes is with insturmention set up to make those low level measurements.
Additionally, here is something to think about.
A 1/4 wave antenna matched down has a certain intercept sensitivity.
A base coil loaded antenna's only electrical difference is a narrower band width from some additional Q.
Besides being a bit shorter, the Q increase makes up in great measure for the shorter physical length in signal strength at the receiver.
It's sensitivity is vertaully the same in the application.
Bottom line is not to get mixed up thinking physical size should make a big difference in this application.
It's again, the electrical properties that are the important items.
Good luck.

You would not expect the loaded Wilson to provide more gain then its full length unloaded counterpart, would you? Granted the differences may be too small to notice in some cases but there is no way around the fact that loading to reduce physical size takes away from gain proportional to the amount of loading taking place.

If only the electrical length of the antenna mattered and the physical size did not, then why doesn't my short cell phone look alike CB antenna have the same range as the Wilson 5000? They are both an electrical 1/4 wave at the desired frequency.

It's not that the Q of the loading coil gives it any advantage over the unloaded antenna. The base coil on most antennas does more than just compensate for electrical length. It also corrects the impedance on the 1/4 wave antenna by allowing matching from approximately 36 ohms to 50 ohms through a tap on that coil. Not a big advantage but the only electrical one the Wilson has over the 1/4 wave whip.

 

[Shockwave]

With respect to coax, it usually does pay to get the good stuff especially on long runs, higher power or frequencies. I can't speak for all "clone" cables but Jefa Tech and at least one other manufacturer are making LMR-400 at around 50% of the price and I have to say the quality is way better then 50% of the Times wire product.

The only real differences are the percentage of the braid being slightly lower (5 or 10% under 100%). That would be unacceptable in most cables that only had this braid for shielding but the LMR-400 series always uses a 100% foil under the braid anyhow. 200% shielding may be great but I'm happy to pay half as much for 190% shielding. The center conductors are the same.

 

[HomerBB]

It's just a shame that we can not highlight the parts of a post we are actually liking.