Sidebar Sidebar
  • You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.

TVI QUESTION

H

hotrod

Well-Known Member
Feb 16, 2007
2,500
369
93
n.w pennsylvania
HOOKED UP A RADIO THIS WEEKEND AT FRIENDS HOUSE
COBRA146 AND A-99 STOCK RADIO AND STOCK MIKE.
NOW HES IN A BAD SPOT IN TOWN SO FOR THE TIME BEING WE DIDNT GROUND
THE ANTENNA CAUSE WE WANTED TO MAKE SURE WE COULD HOOKUP WITH
ONE ANOTHER.IF WE COULD THEN WELL GROUND IT.ANYHOW WITHIN 5 MINUTES OF
TXING WE FOUND OUT WE WERE COMING ALL OVER THE TV THAT DOES HAVE CABLE
WE ARE GOING TO GROUND THE ANTENNA BUT I THINK WE WILL END UP
HAVING TO DO MORE SHOULD I TRY A FILTER AFTER THE RADIO ?
OR A FILTER at the tv set?this tvi was on the ssb mode.in am mode it was slightly worse
i told him to turn down mic gain while in ssb mode but this cobra doesnt have a mic gain
the a-99 has no gpk and is around 25-30 ft. at feedpoint.coax is rg-8
 

Ok well first of all lets try to fix the cable problem...
Is the cable RG-6 3000GHZ rated?
if its rg-59 cable?? replace with the above cable.
No flimsey connectors?
is there a wallplate for the cable?
if so take off the wallplate from the wall and check that connector.. Is that a good connector or 1 of those ugly crimp ons??
Reason why of trying to fix the cable problem 1st?
Ive been helping ALOT of people i know fixing their
cable problem.. in which its not a radio (cb) problem..
Just a few thoughts...

AMPOWER
 
check out the cable installation which was already suggested and make sure it's up to standard but also be aware of the fact that the A99 and other antennas of similar construction were intentionally designed by the manufacturers so that in the event that the radial kit was not used the outer shield of the feedline would be substituted for the missing half of the antenna. because of this, common mode currents are typically present up and down the feedline from the feedpoint all the way into the shack. the point here is that all antenna currents should be generated above the feedpoint of the antenna. radiation from common mode currents present on the shield of the feedline would tend to place rf at much lower elevations than is normal and increase the intensity of any offending energy in much closer proximity to the cable system.

if this is the case in your situation then grounding the antenna will make little to no difference whatsoever.
 
hey jack , if he did 6-8 loops of coax at the antennas input wouldnt it help his problem with common mode currents ?
 
AMPOWER said:
Ok well first of all lets try to fix the cable problem...
Is the cable RG-6 3000GHZ rated?
if its rg-59 cable?? replace with the above cable.
No flimsey connectors?
is there a wallplate for the cable?
if so take off the wallplate from the wall and check that connector.. Is that a good connector or 1 of those ugly crimp ons??
Reason why of trying to fix the cable problem 1st?
Ive been helping ALOT of people i know fixing their
cable problem.. in which its not a radio (cb) problem..
Just a few thoughts...

AMPOWER
Click to expand...
thanks ampower.i never seen that happen on cable.i got cable and previous had dish
i tested that radio here i never had a problem.i cant answer your questions as i just
seen these posts.btw he did same exact thing at his previous qth.i wonder if his
cable company just uses cheap stuff.his radio is not modded up or clipped.so any/all
suggestions will be apprecated.will a gpk help or make it worse.this was on ssb unfornately
a 146 has no mic gain so we couldnt lower modulation to try to solve this
 
Sounds like his modulation limiter has been removed or the modulation potentiometer is cranked all the way up, My A 99 doesn't tear up my over the air TV signal.
 
tell you what Marty , some guys have all the luck , then there are those that just have to fight the TVI aliments of life , and I don't care what kind of freak'in antenna they have , especially on the 11 meter band. Antrons are famously known as the bleed sticks , but it isn't always the case for many whom use them. There are many factors involved , having a scoped out clean transmitting radio is always a plus , but even then , problems will and can occure. I find and have read over the years with the A-99 antenna's that a top notch good quality coax will help in a big way with those antenna's. (you will pay alot more for your feedline then you will the antenna itself) Master Chief is right when he says about feedline and antenna being 90% of everything ( or something like that) I've found out over the years that good coax means alot in many ways , and even the lessening of TVI is always a major plus, it tends to help keep the cancer (RF) in, rather then out. Also grounding and maybe being able to get that 99 shooting for the stars could also be a plus. I've come to appreciate good coax , more so closer to the best ,if i can get my hands on it . Ebay has some very good deals on LMR-400 Times Microwave , and I mean good deals ! even used , that's stuff is still alot better then some of the newer cheaper shit .
 
Last edited:
This is with a brand new stock 68 XL, Barjan RG-8 and a early 1990's Solarcon A-99, on a 20 foot pole.(It was in my attic)
I ran Bendex coax on a 60' tree with a 2 pill once and did not interfere with the TV, maybe some junk alarm clock on some occasion's.:( :;)
 
Installing a TVI filter never hurts. The high pass filters are available for the TV, but not sure if it was your TV or a neighbors TV. Typically purchasing a low pass for the radio is the first step as buying high pass filters can be expensive for more than one TV.

In some cases grounding can cure the TVI.

My personal experience with the A99 is that it sometimes takes a good station and antenna ground, common mode choke (wire wraps), and a good low pass filter all used in conjunction with each other. I believe these are standard practices that also help deter future RF hot spot problems, static build-up in the antenna and station.

Remember the small initial loss with a TVI filter can be less significant with better coax, antenna height and antenna gain (which contributes to overall ERP).

Good Luck!
 
just to add here voice is coming thru speakers and some lines also but not too bad
on the lines.right now hes on vacation.when spring begins well start working on
that tvi issue.thank-you everyone for all your input
 
rg6 quad with the proper connectors for that cable on ALL tvs & from where coax enters the house, plus, it is grounded to its own 8' copper ground rod right there. forget what they are called, but all jumpers from cable boxes, dvd players etc use 'super duty', encased in braid rg6 quad or encased in braid & grounded hdmi/whatever other cables are required. all antennas are aluminum, grounded through ICE lightning arrestors & ICE low pass filters, ALL coax is 9913 or better (lmr600 on 2 & 432....with BIG amps for SSB), into a common ground 'box' that all goes to 4-8' copper ground rods, grounded together. i can dim the lights in my own house yet NEVER touch the tv's, or any accessories INCLUDING PS3, etc, on ANY band. i NEVER run that kind of power in the house-200 watts is MAX, but, 4kw+ ANNIHILATES the neighbors & it makes for an excellent demo! convinced one neighbor to have 6 quad run through his house along with some ground upgrades. he does have a no-name tv w/built in dvd & vcr that experiences overload to the speakers, but otherwise-WE'RE GOOD! even with NO low pass filters, 200 watts on 12-11-10-6 meters does NOTHING.....aluminum, double shield, decent ground & 6 quad.....
 

dxChat
Help Users
  • No one is chatting at the moment.


      Top Bottom
      Back