Blitzortung.org Forum - interference with Ham Radio.

Dear team
I have a question.
I have the mini version at home and works nicely.
But I am also as Hamradio transmitting on 136 kHz 474 kHz and HF and VHF frequencies. I noticed that this gives a disturbance on the mini receiver.
Is this Harm full for the preamplifier , so I should disconnect the preamplifier or using band pass filter for the mini or is this ok and the AGC can handle it.
The output power of the transmitters is max 100 watt.
Thanks
ok8leo

(2025-07-24, 08:28)Ok8leo Wrote: [ -> ]Dear team
I have a question.
I have the mini version at home and works nicely.
But I am also as Hamradio transmitting on 136 kHz 474 kHz and HF and VHF frequencies. I noticed that this gives a disturbance on the mini receiver.
Is this Harm full for the preamplifier , so I should disconnect the preamplifier or using band pass filter for the mini or is this ok and the AGC can handle it.
The output power of the transmitters is max 100 watt.
Thanks
ok8leo

Is your preamp the 23.1? If so, see the schematic:
[attachment=5086]
The signals from the antennae smack immediately into a substantial diode chip. It absorbs everything in excess of maybe 1.4 volts. So there is no danger of your damaging the preamp.

(2025-08-11, 01:40)oppedahl Wrote: [ -> ]...

Is your preamp the 23.1? If so, see the schematic:

Thanks for the schematic!
Where did you find it? I looked around for it and didn't find it right away.

(2025-08-11, 01:40)oppedahl Wrote: [ -> ][quote pid="27250" dateline="1753345722"]
...

Can you tell me what J1 and J2 are for?

(2025-08-20, 20:39)GeezerD Wrote: [ -> ]
(2025-08-11, 01:40)oppedahl Wrote: [ -> ][quote pid="27250" dateline="1753345722"]
...

Can you tell me what J1 and J2 are for?

[/quote]
See this discussion. Apparently you leave them open if you are using ferrites and close them if you are using air core loops.

(2025-08-11, 01:40)oppedahl Thanks a lot for your feedback Have a nice day Wrote: [ -> ]
(2025-07-24, 08:28)Ok8leo Wrote: [ -> ]Dear team
I have a question.
I have the mini version at home and works nicely.
But I am also as Hamradio transmitting on 136 kHz 474 kHz and HF and VHF frequencies. I noticed that this gives a disturbance on the mini receiver.
Is this Harm full for the preamplifier , so I should disconnect the preamplifier or using band pass filter for the mini or is this ok and the AGC can handle it.
The output power of the transmitters is max 100 watt.
Thanks
ok8leo

Is your preamp the 23.1? If so, see the schematic:

The signals from the antennae smack immediately into a substantial diode chip. It absorbs everything in excess of maybe 1.4 volts. So there is no danger of your damaging the preamp.