4 watt MW how far would this go?

[Albert H]

That works, but the HackRF isn't really clean enough for serious use. I have a lash-up here that does a couple of Watts with a HackRF and LOTS of filtering, and can radiate my little 8 stereo channel multiplex a kilometre or two around here. It was just lashed together to see if I could get it going (I was more interested in the DABMUX end of the software than anything else), but I did run a little extra DAB bouquet around here over Christmas and New Year!

[oazz]

One MW installation I've done recently uses a loop aerial - 9m up, 16m across the garden, 9m down and a return at (just above) head height back to the starting point. The part of the vertical near to the house is RG8 coax, and the rig feeds the inner, with the rest of the loop connected to the outer - basically making a long, thin transformer! It matches at about 18Ω, and the rig output stage is dimensioned to match into this directly. Radiation efficiency is surprisingly good, and for a peak DC input power of about 140 Watts, (suggesting a carrier power of around 30 Watts with the kind of efficiency I normally get out of Class E stages), I got daytime coverage that would be the envy of many FM stations!

The antenna design was suggested in a Practical Wireless article "Looping Over The Lawn", back in the '80s. In that case, it was used for "Top Band" - 160m / 1.8 MHz. I was pleasantly surprised how easy it was to get some radiation from this makeshift aerial, and experimenting with a chicken-wire groundplane didn't significantly add to the radiation.

The rig itself is a very simple CMOS synthesiser driving a couple of paralleled FETs for the PA, and modulated by (effectively) a power Op-Amp (LM3886). The most expensive parts of the rig are the mains transformer, the 19" rack box it's built in, and the heatsinks!

I finally got to lash this antenna together last weekend. WOW!! Amazing results. 30 watts into this antenna was clearly heard 10 miles away, with more tests to come this weekend, and, all with no wire radials on the ground, which keeps her happy

Thanks for the heads up on this Albert.

Antenna Practical Wireless article "Looping Over The Lawn" MMANA-GAL

[rigmo]

how to open and see it maa?

[EFR]

Use MMANA-GAL software for windows.

[oazz]

Use MMANA-GAL software for windows.

http://gal-ana.de/basicmm/en/

[oazz]

O