Lighting Arrestors and coax use on antenna?

[RonGT]

I am installing a AM/FM antenna for use in my shop and living in a remote area the signal loss is great.
I would like to use a best coax I can get even though my radio is using a Motorola plug for antenna.
It is a digital unit from a vehicle.
I can change the coax to the appropriate plug, not a problem.
the antenna is using a ham PL259 connector.
My question is this, I have looked at many many lighting arrestors and have asked many manufactures if their arrestors would allow the broadcast frequencies of the AM/FM signal to pass thru. 500khz - 1800 MHz but with no answers.
I would like to use the type with pl259 connector's so I can place right on the antenna.
But it they stop the signal it would be of no use.
I do plan on ground rods and bare copper wire for more protection but would like to buy a good arrestor that will allow my signals to pass thru.
DO any of you know of an arrestor that does this or will all of them work for AM/FM signals?
Thanks
Ron

if I have asked this question in the wrong forum I am sorry and please moderators move to the proper place
thank you

 

[N4GIX]

Many lightning protectors will pass DC-1,000+ MHz, as only the shield is grounded, not the center conductor. The best are "DC blocked" and they will state so in the description details.

DX Engineering has a nice selection from all manufacturers with full descriptions of each product:
https://www.dxengineering.com/search/department/grounding-and-lightning-protection

 

[chief21]

You just need to be careful as to which suppressors you purchase. Some are rated for 1.5 - 700 MHz, some are rated for 10 - 800 MHz, etc., etc. If they don't have a spec sheet that indicates the rated frequency range (and other specs), I wouldn't consider buying that model.

Here is a link to one that should work for you...

https://www.dxengineering.com/parts/ppr-is-50ux-c0

John AC4JK

 

[mmckenna]

To cover the AM broadcast band, you'll likely need one that allows "DC Pass". The cutoff frequencies on the non-DC pass units are usually around 1.5MHz, or the top end of the AM broadcast band.

Patented Coaxial RF Surge Protection - PolyPhaser

Polyphaser is pretty much the industry standard for this kind of stuff.

While they do have a very slight amount of insertion loss, using a good antenna and good coax will make it un-noticeable.

 

[RonGT]

Arrestor or polyphaser?

Thank you John,
so something like DC-2.4GHZ would work ok?
What is the difference in the arrestor and a polyphaser?
Could you recommend a quality coax for the AM?FM reception ?
I would like to use the PL259 239 type connectors but want impedance to be right,
I am only receiving and not transmitting.
I have contacted DX about their arrestors.
Ron

 

[chief21]

Any suppressor that passes DC with a frequency range up to the highest frequency you might wish to hear should work for you.

At such low frequencies virtually any coax would work. However, if you're looking for quality coax with minimal loss, I would suggest Times Microwave LMR400 or other quality brand-name RG8-type cable with low-loss specs. How long will the coax need to be?... the longer the run, the greater the need for low-loss cable.

You mention wanting the correct impedance... the coax noted above is 50 ohms. PL259 connectors are also 50 ohm. Are you sure that your vehicle radio expects the same, although in practical terms it probably isn't that significant.

To my mind, the terms RF surge protector, lightning suppressor or arrestor are functionally identical. The biggest differences are quality and construction. Understand that no device will protect from a direct lightning strike, and even high-quality suppressors must be properly installed to achieve maximum protection. As pointed out by mmckenna, Polyphaser is pretty much the commercial and government standard. Much cheaper units will likely provide little protection and/or greater insertion loss.

John AC4JK

 

[RonGT]

Thank you John,
both my antennas have a 239 type female connector to tie into.
Coax suggestion?
I plan on looking at the PolyPhasers if someone could suggest a good one, Want to connect straight to the female antenna connector if possible to reduce the number of splices and connections.
I know they will not help against even a close strike but was wanting to get some protection and I think the ground rods are possibly the better of the options but trying for all the insurance.

The Radio has the mini type Motorola plug found on many vehicles over the past decade or so.
I can make a good splice in about any thing but will reduce to the mini plug with the aid of a short 6" factory made adapter.
So the only splice I will have would be the larger old type Motorola plug on the end of what ever coax I use.
Coax run of approximately 20 feet.
Ron

 

[RonGT]

coax, polyphaser?

Thank you John,
The radio has the small mini Motorola Plug in the rear like most all autos have in the past 2 decades.
I wont change that but will use a Metra factory adapter up to the older Motorola type so I could use about any coax on up to the antenna then. About 20 foot run.
So what would best , best shield and lowest noise?
But want to use the least amount of splices to antenna so need to put a pl259 on the end.
I think I will look at the polyphasers too if anyone could recommend a good one that will work on the AM/FM.
I would like to place it right on the 239 antenna stub so I could connect the other end right to my coax , with no more splices.
Yes I intend to use some #6 bare copper to ground rod to.
just looking for the most insurance
Ron

 

[mmckenna]

What, exactly, are you going to use for an antenna?

There are a lot of options that will work, but since it sounds like you are on the "fringe" reception area, you may want to pay close attention to what antennas you choose since that will make the largest impact on how well this works.

For AM broadcast band, loop antennas are best. You can make one yourself pretty easily if you search on the internet.

For FM, it will depend on where the stations are you want to listen to in relation to your location. If they are all in one general location, a purpose built FM Yagi antenna will work best.
If they are in multiple directions, there are omni-direcitonal antennas that will work well.

Getting a good antenna system in place will get the strongest signal to your radio. While low loss coaxial cable is important, you have to have a strong signal to start with. No point in doing a half way antenna system, then spending a bunch of money on cable if it's not going to work.

On AM broadcast and even FM broadcast, the frequencies are low enough that coaxial cable losses over the 20 foot run you mentioned above are going to be minimal. Using something simple like RG-6 will work just fine. It's inexpensive, you can find it anywhere, and installing your own connectors is really easy. The standard TV/Cable TV/Satellite system "F" type connectors will work fine.
You can can even get inexpensive grounding blocks for consumer TV antennas that will be more than sufficient and save you some money. No need to spend a bunch of money on high end lightning arrestors and coax if you are just going to use this to receive AM/FM broadcast radio. It's not going to work any better, at least not that you'd be able to hear by ear.

A basic FM broadcast antenna and an AM loop antenna mounted and cabled correctly should work very well. Getting the antenna outside your shop and up above surrounding structures is what is going to make the difference. Not expensive coax on a 20 foot run.

 

[RonGT]

I have tired many of the fringe" type FM antennas and some old TV uhf type antennas, some worked OK and some not so good.
I made these last 2 antennas from pieces of old ham type components.
As I have seem and examined some of the local antennas that work pretty well.
I have even bought and used better type radios like Sangean and Boston etc.
This time I am using a vehicle radio because even with a cheap factory 32" stainless whip moving at Highway speeds these radios pickup better than any radio I have used in the past.
So I bought a radio model of one in a pickup that had the best reception I had heard.
Surely I could improve on the 32' stainless whip with a single coil of wire wrapped around it for an antenna?
Ron

 

[mmckenna]

Vehicle radios tend to be good performers.

If what you have works, then stick with it, no need to change it.

Where are you located, if you don't mind me asking?

 

[RonGT]

I have thought about using a good factory OEM radio for years finally did some research on the net about it and what type of power unit etc, I was surprised I was not the only one thinking about it , it was loaded with ways to do it, some stupid and not so good some were very good ideas.
Texas High Plains

 

[mmckenna]

OK,
I just traveled through the southwest US and did a lot of driving at night. The radio in my truck did a great job of getting AM stations from all over.

Sounds like a good solution you have. I'd give the vehicle antenna a try and see how it works. It'll likely want to see/work better with a ground plane under the whip. You might need to add some radials under the antenna connected to the outer shield of the coax cable. This would mimic the vehicle body under the antenna, like it would have on a car install.

 

[RonGT]

On one of the antennas has what I am calling a ground plane the other does not have one.
This ground plane has some 2 foot long rods attached to the plane(base) are these what you call radials?
if so , attach some of the shielded wire from the coax to the ground plane since the plane and rods are all the same grounded metal, which will also be grounded to the ground rod via bare copper wire.
???
Ron

 

[mmckenna]

Correct.

For a ground plane type antenna, there are two parts:
The "radiator" which is connected to the center of the coax.
The "radial" which is connected to the coax shield/ground.

 

[RonGT]

Coax use

Should I use a coax like RG62 or RG8 some 75ohm or 50 ohm? one run will be about 20 feet the other on anther antenna is about 40'.
Both antennas have the 3/8x24 stub to start with but both antennas are to be used on AM/FM radios.
One radio will have only a Motorola plug end at the radio and the other radio will have a AM/FM band separator on the end of its coax run with F connectors,
the FM side of that radio is a F connection but the AM side is the old 2 screw flat cable hook up.
On that hook up could I use a piece of coax out of the F connector at the band separator and then just split the coax and install 2 eyelets to connect to the AM screws?
Ron

 

[Rred]

I'd also vote Polyphaser. They are "spark gap" protectors. There is a ground connection that goes into a vacuum chamber and up very close to the antenna cable where it is routed through the Polyphaser. So, there's no interruption in signal, normally. But when there is high voltage hitting the antenna, it arcs over that tiny gap and goes to ground, instead of coming down the coax and into your premises. Their customer support is also very good, they don't mind talking to small customers.

Still, the best practice with an outside antenna is to get in the habit of physically unplugging the cable, outside your premises or at the bulkhead entry, and plugging it into a ground right there--so it can't come into the equipment or building. That's a PITA, yes, but that's the failsafe way to do it. You only plug in the cable when you want to use the radio, you ground it the rest of the time.

Have you tried taking a portable AM/FM radio up to where you plan to put the antenna? I ask because the extra few feet of height may or may not actually make any difference. If you can't hear an obvious difference, then the extra signal loss in the longer antenna cable may just eat up any advantage the antenna would have, and putting it indoors would be just as effective.

And if you have any fluorescent bulbs, or the new LED bulbs? See if there's a difference when you turn them off. I've found the new LED bulbs, even brand names, can really kill radio reception. (In which case, an antenna outside an away from them could be a really good thing.(G)

 

[RonGT]

still need advice.

Yes , I will use the polyphaser on both antennas along with a good ground to rod,
I hope someone would reply with the comments on my above last post about the coax type to use.
Also , I have a 1.5" diameter mast ready to mount an antenna on, I would like to use a simple angle bracket that will use 2 U type clamps and has a hole for an 3/8 n type connection.
I have looked everywhere and have not seen them yet.
I have some stainless I guess I could fabricate them.
Ron

 

[mmckenna]

Should I use a coax like RG62 or RG8 some 75ohm or 50 ohm? one run will be about 20 feet the other on anther antenna is about 40'.

For the relatively short runs at these frequencies, you don't need to be too concerned about coax. 75Ω or 50Ω isn't going to make a noticeable difference. Either of those would work fine. RG-8 or RG-6 would be pretty close to the same. I'd go with the RG-6 since you can get it at nearly any hardware store, radio shack, etc. Installing connectors is easy if you use the sealing type F connectors, which should be sold alongside the cable. They do a good job of making a fairly foolproof connection.

Both antennas have the 3/8x24 stub to start with but both antennas are to be used on AM/FM radios.

So, 3/8 x 24 is pretty common for CB antennas. Shouldn't have a problem finding 3/8 x 24 to SO-239 (UHF) mounts. You are probably going to need an adapter as RG-6 to UHF type connectors are not necessarily easy to find, but if you are good with a soldering iron, you can make it work.

One radio will have only a Motorola plug end at the radio and the other radio will have a AM/FM band separator on the end of its coax run with F connectors,
the FM side of that radio is a F connection but the AM side is the old 2 screw flat cable hook up.
On that hook up could I use a piece of coax out of the F connector at the band separator and then just split the coax and install 2 eyelets to connect to the AM screws?
Ron

Yes, that would work just fine.

 

[RonGT]

Thank you mmckenna,
I have most all of it except the angle bracket needed to clamp the 1.5" mast.
East enough to build so I guess I will.
I have some RG8 and 6 some 59 and 62 , will use the 8
I think I saw in my search some pl-259 female connectors with the F female on the downstream side.
I will back track.
Thank you,
Ron