You do have yourself a pickle there.... But
legally it is your father's responsibility to insure he does not interfere with your playing. That's all part of Ham radio. You can't interfere with others.
Ham output can be up to 1500 watts and depending on how good and centered his transmitter is, he may be bleeding over a good range to either side of the center frequency.
What's his TX power, how big of an antenna does he have, and what band(s) does he use?
Your best bet is probably going to be the use of torriods or some other shape of ferrite filter. The idea here is that you don't need anything in your guitar signal above say 50KHz (to be really sure) so you need a low-pass filter that scrubs the RF.
Ferrite filters come in a variety of shapes, the most popular being a cylinder of one form or another. There are "clip-on" ferrites that you just clamp over a cable, but you should loop the wire through the ferrite a few times if you can. The other standard style is a ferrite doughnut in a torriod shape. Same applies here... wrap your guitar cable through one a few times.
Your problem is that at least one of your cables is acting like an antenna. If you place the filter in the
middle of the cable, you change the frequency and hopefully stop the interference. Play with the placement for best results. Also keep in mind that you could have the pickup in ANY cable in your setup including the power cable!
Ferrites are made of different materials for different frequencies.
Material Attenuation Range
75 or J = 0.5 - 10 MHz
(160, 80, 60, and 40 meters)72, 73, 77 = 1 - 40 MHz
(160, 80, 60, 40, 30, 20, 17, 15, 12, and 10 meters)43 = 20 - 400 MHz
(15, 12, and 10 meters)31 = 1 - 500 MHz
(all HF Ham bands)61 or 64= 200 - 2000 MHz
(VHF ONLY)I use 73, 75, or 77 material for filtering HF Ham traffic in the 160-40 meter bands. Type 43 material gets useful for people operating in and above the 20 meter band. I've never used 31 material, but just because I don't have it available off-the-shelf. You can always use multiple filters. Once you find a combo that works, toss a little more filtering in to be sure.
Your amp has an input resistor, which is there to remove broadcast RF. In Fenders, you see 34K from two 68Ks in parallel at the input jacks. You can insert a torroidal choke (with material selected for frequency) in series with that resistor. Get a torriod 2-3cm in diameter and wrap a dozen or so turns of wire through it and presto. You could also try a shield around your 1st preamp tube if you don't have one now (assuming a tube amp :wink:).
If the noise if coming through the power lines, try adding a good "hash" filter to the power in. These often come as sealed metal boxes with solder tabs for ins and outs. They are also called EMI/FRI filters.
If your interference is being picked up by a high gain pedal, you have a much tougher task. Put some filter between the guitar and pedal.
You could always line your room with copper mesh and make a Faraday cage to play in. :wink:
I have a friend with a 100 watt rig and a ~250 foot long antenna. His PC speakers picked things up loud and clear. One clip-on ferrite later, problem gone. Same problem with the external amp on his Ham rig. Another ferrite, another solution. Similar problem in his mobile at 100 watts except that it caused the in-dash radio to blurt out noise at volume 11 even with the radio off when he used a section of the 40 meter band. Same cure... two clip-on ferrites near the in-dash radio. Problem solved.
This is a good test for your Father. According to the rules, it’s his responsibility to supply you with the proper filtering. I wouldn’t push that too far though.
Good luck!
-Peter
73 and clear
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