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Choosing a dual final export that doesn't cause RFI/TVI

S

Snake_Eyes

Member
Oct 16, 2005
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I need help please in choosing a dual final export radio that will NOT interfere with my neighbors' television sets. And, how would I want it tuned?

I plan on purchasing a new radio (no preference on base or mobile), and only care about NOT interfering with nearby electronic devices (in my house or the houses nearby)...

If I have to deal with low modulation, then that is something I will look at...

Please give me the scoop as I really don't know how to request a radio to be tuned to NOT interfere, and want to check here before ordering one.

A lil history...

My station is grounded, and I am using a Top One Ground Plane with a low SWR, mainly on 27.205 MHz AM.

I am open to the idea of an Ice Low Pass Filter, or any other low pass filter that forum members have had success with on 11 meter.

I've tried the high end Bencher, and a high end Common Mode Filter on two dual final exports... and, both "bleed" onto electronic devices with 2 watt and 6 watt deadkey's, respectively!

So, maybe the problem is indeed in how the radio is tuned?

Thus, I'm looking to you all who know more than I on this subject, and am open to everyone's suggestions here. If you have any questions for me, just ask!

Thanks for your help!
Snake Eyes
 

*Modulation set below 100% at the peaks.
*Proximity of antenna to a neighbor.
*Antenna needs to be up high enough.

Any radio is capable of throwing off TVI; doesn't matter if it is single or dual final radio - domestic or import.

Some Hams will use an MFJ-931 to tune their ground system. This can help a lot; don't know if it is necessary if the first three steps are maximized.

I have found out that using clamp-on type ferrites on my mouse, keyboard, and speaker wires eliminates any computer problem. Put the ferrites on the middle of these cables - not on the ends - as this will break up most harmonic intervals of the wave. Worked for me!

I read recently read on another forum, where a guy would cause a can of shaving cream to burst whenever he keyed up. Went through a few cans of shaving cream before he decided to get his horizontal beam antenna up high enough. I think that says something...
 
My antenna is a full wave length or slightly better off the ground, Carl... and am close enough to shake hands with my neighbors, Robb.

What is that you are saying about 100% modulation?

Do I want a radio tuned for no more than 100% modulation?

Thanks!
Snake Eyes
 
Snake_Eyes said:
My antenna is a full wave length or slightly better off the ground, Carl... and am close enough to shake hands with my neighbors, Robb.

What is that you are saying about 100% modulation?

Do I want a radio tuned for no more than 100% modulation?

Thanks!
Snake Eyes
Click to expand...
Modulation that is more than 100% at the peak can splatter over and throw off a lot of harmonics that can bleed into various consumer electronics.

There is no guarantee that you will be successful with curing TVI.
The BEST you can do - is do all that you can...
 
That is 100% PEAK modulation, not 100% average modulation. Modulation should hit 100% only at voice peaks occasionally when speaking loudly into the mic, not ride there most of the time.

What kind of equipment are you currently running?

Do you run a power mic? If so, switch to a stock mic and see if that helps any.
 
Antennas generally are not the cause of TVI. I certainly have never heard of the Top One having any such issue. I had one here for a year or two, no issues with it.

TVI is usually something wrong with your SIGNAL, not the radiator.
 
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Highlander_821 said:
Antennas generally are not the cause of TVI. I certainly have never heard of the Top One having any such issue. I had one here for a year or two, no issues with it.

TVI is usually something wrong with your SIGNAL, not the radiator.
Click to expand...

strictly speaking highlander that isn't true,poor antenna design can be a major cause of tvi due to imbalance of the rf currents causing common mode current on the transmission line.The Antron 99 is a classic example,as are many other end fed antennas without radials.

but more often than not nowadays its piss poor domestic appliance design that is the major cause of rfi no matter how clean your signal is as the manufacturers are too tight @rsed to fit a few dollars worth of components that would make these appliances literally immune to rf,and the governments are letting them away with it due in no doubt to the massive backhanders they are receiving.

you can do just about everything your end to clean up your setup but if the rfi is due to rectification of your signal by poorly shielded/filtered equipment theres not much you can do except buy your neighbour a decent telly.using FM like we do in the uk can help as there is no varying amplitude in the signal for piss poor equipment to rectify,but even that isn't foolproof if your overloading the front end of a poorly designed tv receiver.

as for a dual final or even a single final radio that doesn't cause rfi/tvi,if you find one let me know because its the holy grail of 11m pirates.
 
If I was having your problem Snake_Eyes, the first thing I would do is; pulled down the Top One and replace it with either a Maco 5/8's or I 10K, you might find that this could stop the problem.

But - I would also try different radio's with stock mic's too. Just to see if it's the radio or the antenna.
 
Robb said:
I read recently read on another forum, where a guy would cause a can of shaving cream to burst whenever he keyed up. Went through a few cans of shaving cream before he decided to get his horizontal beam antenna up high enough. I think that says something...
Click to expand...


Robb, you have got to stop hanging out on that forum. :headbang

Either that or learn what "in jest" means. :whistle:
 

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