Mobile DX'ing

[Littlecloud319]

So i would like to know what i can do to improve my DX ability with my mobile setup.
I have a Uniden 980SSB with a Larsen NMO27C on a magnetic base on the center of my roof. My SWR is around 1.2-2.0 and is as low as itll go and has provided excellent signal both RX and TX.
Ive been thinking about getting a kl203p amp which i know will help with TX but om wondering if theres anything i can add to strengthen RX for DX'ing purposes?


And yes im fully aware of the circumstances with using an amp so please assume i dont care about the legality of using an amp.

 

[slowmover]

West Mountain Radio CLEARSPEECH DSP Speaker.

 

[toolman60]

Wait for improved sunspots. Will not need all that extra stuff in line.

 

[jhooten]

Running an amp with a mag mount is a recipe for disaster.

 

[jonwienke]

Do a permanent antenna install before running power. Mag mount power ratings tend to be rather optimistic.

 

[Duckford]

I run a 102" whip on a Tram triple magnet mount. Should I be worried if I ever put some serious power through it?

Is the problem in the magnet mounts, or the magnet mount antennas?

 

[RFI-EMI-GUY]

I run a 102" whip on a Tram triple magnet mount. Should I be worried if I ever put some serious power through it?

Is the problem in the magnet mounts, or the magnet mount antennas?

No problem, just some bubbled paint....

 

[FiveFilter]

I run an RM KL 203P with mag mount antennas without problems. I have read that if you want to use really powerful amplifiers that you might find the paint beneath the magnet has been affected. The reports I've seen imply some discoloration or crazing of the paint from the heat buildup beneath the magnet, but only at very high power levels. How high a level of amp-power will it take? I suppose it "depends" on the paint and how long the operator talks when transmitting. Here is a post on the topic that might give some guidance:

"I ran a 1x4 [amplifier] through a Wilson 5000 magnet mount for years with no problems. No paint burn. So did King Cobra. I'm not saying that there aren't better ways to go, but 4-500 watts should not burn your paint."

I haven't any experience with the big amplifiers. All I know is that the 203P has not affected my paint job during the five years I've been using it with my mag-mount Wilson antennas. And the preamp feature of the 203P is quite effective in boosting the reception when the incoming signals are weak.

 

[FiveFilter]

I run a 102" whip on a Tram triple magnet mount. Should I be worried if I ever put some serious power through it?

Is the problem in the magnet mounts, or the magnet mount antennas?

Wow Duckford, your tall-boy whip should yield about the best performance of any mobile antenna out there. I don't have the guts to run a quarter-wave on the roof of my vehicles, but the payoff has to be unexcelled antenna performance for a mobile unit.

About the effects on your paint job: As noted in my recent post in this thread, it would likely take a really large amplifier to affect your paint. It's also possible that spreading the power heat amongst your three magnets might serve to lessen any such effect. Let us know if you ever try it.

 

[Duckford]

Wow Duckford, your tall-boy whip should yield about the best performance of any mobile antenna out there. I don't have the guts to run a quarter-wave on the roof of my vehicles, but the payoff has to be unexcelled antenna performance for a mobile unit.

About the effects on your paint job: As noted in my recent post in this thread, it would likely take a really large amplifier to affect your paint. It's also possible that spreading the power heat amongst your three magnets might serve to lessen any such effect. Let us know if you ever try it.

I hit a lot of things with it, people will stare, and I can't drive through the bank drive through anymore.

But, yes, the performance is amazing. Once you use 1/4 wavelength you understand the true potential of 10/11 meter, even at QRP. Suddenly practical CB ranges are 8-10+ miles even in trees and other poorer conditions with type accepted equipment. When skip rolls in, you hear all of it. It really works, and makes all the problems of having that great big thing slapping around worth it.

100 watts PEP is the most I've put through it in testing. Which isn't too much, but I'll try something a little bit heavier some time.

My radio cars are old beaters, so the pain is the least of my concerns.

 

[slowmover]

I hit a lot of things with it, people will stare, and I can't drive through the bank drive through anymore.

But, yes, the performance is amazing. Once you use 1/4 wavelength you understand the true potential of 10/11 meter, even at QRP. Suddenly practical CB ranges are 8-10+ miles even in trees and other poorer conditions with type accepted equipment. When skip rolls in, you hear all of it. It really works, and makes all the problems of having that great big thing slapping around worth it.

100 watts PEP is the most I've put through it in testing. Which isn't too much, but I'll try something a little bit heavier some time.

My radio cars are old beaters, so the pain is the least of my concerns.

Well said.

 

[Littlecloud319]

I hit a lot of things with it, people will stare, and I can't drive through the bank drive through anymore.

But, yes, the performance is amazing. Once you use 1/4 wavelength you understand the true potential of 10/11 meter, even at QRP. Suddenly practical CB ranges are 8-10+ miles even in trees and other poorer conditions with type accepted equipment. When skip rolls in, you hear all of it. It really works, and makes all the problems of having that great big thing slapping around worth it.

100 watts PEP is the most I've put through it in testing. Which isn't too much, but I'll try something a little bit heavier some time.

My radio cars are old beaters, so the pain is the least of my concerns.

I get about 18 miles with skip inference and a few more without skip interfering.

 

[mmckenna]

Using a magnetic mount over a permanent mount adds a bit of loss to the antenna system. Not a lot, usually about 0.1dB, not enough to be noticed. But that's if everything is perfect.

Other issue is that while a magnetic mount can supply a capacitively coupled connection to ground, it's not as good as an actual ground connection at the antenna base. Since the matching coil at the base of the NMO-27 needs a ground connection, your install may result in some of the energy being radiated by the coax, which isn't ideal.

If you are looking at adding an amplifier, you are probably wanting to get the most out of your system. Taking the extra steps to do a full install would be worth your time.

But I get it, not everyone has the tools/skills to do a permanent antenna install. Not everyone wants to drill a hole in the roof of their car.

However, it would be a good idea to look at this as an entire system, not individual parts connected together.
Running 100 watts through a magnetic mount probably isn't going to damage your paint. Probably a ton of amateur radio operators doing this without issue. But the more of that energy you can get properly radiated by the antenna, the better.

 

[jhooten]

Other issue is that while a magnetic mount can supply a capacitively coupled connection to ground, it's not as good as an actual ground connection at the antenna base. Since the matching coil at the base of the NMO-27 needs a ground connection,

AND, it is not possible for the grounded end of the coil to bleed off built static charges through the capacitive "ground" of a mag mount as it is a DC voltage. So the built up static travels down the coax shield to be dissipated through the chassis of the radio. Usually through some sensitive semiconductor component. Driving through the west Texas dust storms can generate some decently high voltages.

 

[GadgetGeek]

So i would like to know what i can do to improve my DX ability with my mobile setup.
I have a Uniden 980SSB with a Larsen NMO27C on a magnetic base on the center of my roof. My SWR is around 1.2-2.0 and is as low as itll go and has provided excellent signal both RX and TX.
Ive been thinking about getting a kl203p amp which i know will help with TX but om wondering if theres anything i can add to strengthen RX for DX'ing purposes?


And yes im fully aware of the circumstances with using an amp so please assume i dont care about the legality of using an amp.

I have had great results with the Sirio 5000 Performer and matching PL145 mag mount.

I have not had any issues running 100 watts into a mag mount.

 

[FiveFilter]

Yeah, I've had excellent performance from my mag mounts too. They seem to communicate as well as any others I've seen, inch-for-inch. That 0.1db loss factor is too small to be heard and so can be disregarded as far as I can tell.

About the static charge topic, I haven't noticed any static charge problems through the years. I don't live in Texas so haven't experienced any dust storms there, but I did drive through one in New Mexico on vacation one time, but didn't notice any problems with the radio. In the wet Louisiana climate I live in, we do get static charge build-ups in stormy conditions with lightning, etc. I do make sure to ground all of my radio chassis to the vehicles chassis to assure any common mode current is bled off, and I suppose this would serve to bleed off any static charge as well. It's a good thing to do for any mobile radio with an external antenna.

 

[Littlecloud319]

Whats a good 100w amp with preamp that wont take a month to ship? The kl203p gets shipped from HK and takes a month so im looking for an alternative.

 

[slowmover]

Whats a good 100w amp with preamp that wont take a month to ship? The kl203p gets shipped from HK and takes a month so im looking for an alternative.

There’s gear unavailable today that’s been in stock for ages, otherwise.

You want it, submit the order. Might not be there next time. Or ever again.

88Radio (on NEWEGG) says shipment arrives 5-9 days from Fremont, CA (DNJ whse).

9 days? 21-days? So what?

 

[p1879]

Conditions are improving, and the early summer skip season is approaching too. You might be amazed as to what a radio like a Uniden 2510 or like can do on SSB as the cycle kicks in. Never have run an amp, but had some great skip contacts in previous cycles. A Wilson 1000 behaved well, and the big "Skipshooter" antenna even better. Trans- Atlantic DX is a hoot while mobile.

 

[2IR473]

Like it was mentioned early on in this thread...if you want to work DX, you are going to have to wait for the proper band conditions. Back in the mid-1990s, the band was in great shape and I worked oversees stations everyday from my mobile with a Wilson 5‘ Silverload fiberglass antenna and an RCI 2950 25 watt radio. Working stations across the U.S. was easy as well. That antenna was mounted in a stake hole on the bed of a pick up truck, and I worked the world from my mobile.

These great conditions were mostly from F-2 propagation. What we generally see at 27 mHz is e layer propagation, and that is typically only good for a few hundred to a thousand miles (yes, double hop basically doubles that distance). The conditions we have experienced over the past couple of decades have been pretty bad when compared to earlier solar cycles. Yes, the band does open up at times, but not like 25 years ago. It was open day and night.

Adding the KL-203 can’t hurt with local ground wave stuff, and it will get you another s-unit or two in someone’s receiver, but if the band is dead and no one is listening, dropping the maul or running AC Sky won’t make much difference. And take care not to overdrive the KL-203. They are pretty intolerant to too much input. Keep the carrier on your 980 to 2 watts or a tad less. Those radios don’t have much “swing”, so you will be ok. I run the President equivalent to the 980, a Grant II (single final radio...kind of hard to find in the US) with a KL-203 in my vehicle. It is fine, and I can run on 11 and 10m with this radio. With that setup (and an old Radio Shack 21-988 64” whip antenna), I have worked back to friend’s base shacks at distances of nearly 40 miles. YMMV...literally.