SWR issues with more power..

[CB590]

I'm going to buy a ground rod and drive it in a few feet from the antenna mast pipe and try grounding that. (All mast sections are screwed with self tappers at each section).

Then I just ran a ground wire out the basement wall for the amplifier to get hooked to (via screw on side of casing) and ground that to the same ground rod point (thinking same ground point is correct way).. No way to really ground the radio.. it's going to antenna via coax (shield) and also grounded with the PS. So technically there all linked.

Try this tommorow morning as I work till 10pm..

 

[Road Squawker]

... edit....

Then I just ran a ground wire out the basement wall for the amplifier to get hooked to and ground that to the same ground rod point
No way to really ground the radio.. it's going to antenna via coax (shield) and also grounded with the PS. So technically there all linked.

..

That confuses me,...... HOW is the radio/coax braid "grounded" to your PS?.

The radio chassis ground lug (and the PS too, for that matter) should be connected to your ground rod (same as the amp).

Actually, they all should be connected to the same point where your elect utility drop is grounded............ sometimes this is physically hard to do.

 

[CB590]

Sorry forgot about the side mounting screws on the radio.

I can ground the amplifier to the new groundwire tommorow and obviously the A99 would be grounded also to the same rod.

I will use the mounting screw on the side of the AT-6666 to ground to same rod tommorow as well.

Therefore all grounded together.

The PS will be on the house 120VAC and that rod.. it's on opposite side of house so that isn't happening.

 

[DainBramage]

So,.... you will have the radio, antenna, and amp on one ground rod, and the PS on 120 VAC on a different one.

Not the best method, but, sometimes,.......

 

[CB590]

So with the mast outside and the radio and amp tied to it I get a slightly better like 2.25:1 or so on AM with amp on medium.



Without is was like 3.75:1.

Tommorow with new rod in maybe numbers will change..

 

[Jay Mojave]

There is a possibility that the amp output impedance is NOT tuned to 50 Ohms. Also I have seen the A99 type antennas have a increased VSWR with higher power levels as compared to lower power levels, and I think this is due to the A99 internal impedance matching circuit physically moving or components changing value with the higher power levels. I know from experience that some of the A99 / IMax 2000 antennas do change VSWR with higher power levels and then some don't. Good luck, please share what all you find wrong or the fix.

Jay in the Great Mojave Desert

 

[CB590]

Well I only had some 12awg black wire here so about 18" of that to the 8' copper clad rod.. the white is from inside the shack to the rod and that's 12awg THHN.. got to get some 4-6 awg tommorow for at least the mast to the rod part.. that's 3M rubber tape for now..

 

[CB590]

No change in SWR would grounds setup.

Next is pull the 1:1 choke and see what happens..

Anyone have the exact parts list to use a 102" whip for a base antenna and what type of collar (other than A99 GPK one) to use 2-3 other 102" whips as the GP for it??

 

[M0GVZ]

A ground rod does nothing for RF grounding as RF only penetrates a couple of inches from the surface of the soil. That wire is also doing nothing for a RF ground if that was your aim. RF flows on the surface of a conductor and not through it so to get the same surface area and conductivity as flattened braid you'd need to be using 0000 gauge cable.

As for the 102" ground plane antenna. All you need is four lengths of wire 102" long and connect them to whatever 3/8th mount you decide to use that you screw the antenna into.

 

[CB590]

As for the 102" ground plane antenna. All you need is four lengths of wire 102" long and connect them to whatever 3/8th mount you decide to use that you screw the antenna into.

Could I use a 3/8-24 mount on the top of the 1 1/4" mast pipe and just below it (like 1-2") use say the A99 ground plane kit with 4 of the same 102" whips as radials. The mast would act as part of the ground I would surmise till the radials kick in.

The A99GPK uses a collar and it has a 1 1/4 - 1 3/8" diameter inside dim to slide on..

If someone can suggest a vertical without this A99 type tuning rings that is under $100 I may entertain swapping that in for A99 if it will give me a flat(ter) SWR and handle 400-500w if needed.

 

[Shadetree Mechanic]

A starduster is $73.

 

[kopcicle]

I just can't resist...

handle 400-500w if needed.

^^^was the trigger.

A starduster is $73

Any 1/4 wave (Starduster included) is an option. (link please?)

I will only modify my long standing opinion this much. There are places and situations where one of these "antennas" is the only option and there , it's better than nothing. This has never in my experience included even moderate power ie: pair of transistors or small tubes @ 100 watts.

Really I'm not trying to be a dick I just , well, okay , I'm a dick ...

 

[Shadetree Mechanic]

https://www.copperelectronics.com/cart/Antennas-Towers/CB-Antennas/Base-CB-Antennas/M400-10-11-Meter

 

[Jay Mojave]

Kopcicle good one. Accuracy over punition and feelings. yep

Jay in the Great Mojave Desert

 

[543_Dallas]

Could I use a 3/8-24 mount on the top of the 1 1/4" mast pipe and just below it (like 1-2") use say the A99 ground plane kit with 4 of the same 102" whips as radials. The mast would act as part of the ground I would surmise till the radials kick in.

Yes, but I would get the ground plane kit as close to the feed point as possible. The mast is probably galvanized and will cause some issues eventually. Bond it to the mount or the coax shield. Don't rely on the mast to make the connection.

Wire is cheaper and can be trimmed to adjust the viswars.