Today I built a quick prototype of a dual attenuator box. One side is an 8 dB attenuator, the other side is 20 dB. I've attached a photo to help explain the 8 dB tee attenuator I described yesterday.

If anyone wants to get their soldering iron out and make an attenuator with three resistors then a simple 8 dB tee attenuator can be made from two 22 ohm resistors, one 47 ohm resistor and two coax so

For HF use I would suggest 6 or 10 dB, 1 dB is too small to have any real effect on the matching. The background HF noise level from most antennas is probably 20 dB above the receiver noise floor so a

I don't have an RSP2 or RSPdx to test but it's would still be good practice to add an attenuator for HF use. The advice from Tom, G6PZZ is very sound. Regards, Chris

Either attenuator would work especially at HF. Regards, Chris

Recently we have had reports of high noise and possible intermodulation problems with all versions of the Loop Antenna Amplifier. This only seems to occur when used with certain SDR receivers. Thanks

Thanks for sending the photo. I'll send a new version 4 base unit board with your Multicoupler so that you can compare it. Regards, Chris

Yes the loop has to be balanced so that it doesn't act as a electric field antenna. In our Loop Antenna Amplifier we also add common mode chokes to isolate the loop as completely as we can from the co

Just thinking about the difference between the two loop screenshots have you tried a different 5 V USB power source for the antenna? My early testing of the prototype and production models was done wi

Sorry for the delay with the Multicoupler. My assistant has been off sick for two weeks so I'm running everything. I've got a batch of 10 Multicouplers nearly completed and I had held off replying to

I would recommend the VLF/HF version for apartment use if you don't need VHF. One advantage of the loop antenna is that it is not sensitive to the electric noise field radiated by the electronic devic

Thanks for spotting that. Yes it should say HF/VHF. i corrected it a few minutes ago as it really confused me when I printed an order out this morning! Regards, Chris

The HF/VHF Loop Antenna Amplifier head unit is more tolerant of loop type and size than the original VLF/HF unit. If you are mounting it at height on a rotator then the physical strength and looks of

A second question...which version of the Loop Antenna Amplifier do you have? Version 1 had single sided PCBs. Version 2 had double sided PCBs. Version 3 had double sided PCBs with an 82 pF across the

Thanks for posting that, Brent. A question...what size loop were you using with the Loop Antenna Amplifier? Regards, Chris

As you might imagine I've had a lot of feedback from customers and potential customers since we released the Loop Antenna Amplifier. The feedback covered three main areas: Can it use a bigger loop tha

Oene, I would ask you to measure the whisky cylinders but it would spoil Tom's fun! Here is the best coil inductance calculator I've found: https://hamwaves.com/inductance/en/index.html#input Regards,

The price of "ham radio antenna rotators" has gone through the roof in the last few years. I did a quick search on eBay and came up with a lot of CCTV pan/tilt units and controllers using RS-485 wire

I used the alloy bicycle rim as the loop element. On the bicycle wheel rim I've adapted I cut across the large hole for the tyre valve then fitted nuts and bolts in the sprocket holes either side of t

The Loop Antenna Amplifier is designed to be used with a small metal loop up to 1m diameter. It is supplied with a 3m length of wire which can be used as a triangle with 1m sides or wrapped around a p