Re: Off the shelf amplified antennas for LW and AM BCB?


Michael <michael.setaazul@...>
 

The various external ferrites for uldx receivers described on this
site are by far the best compact solution.

The varactor automatic tuning capacitor in the DSP chip and the
tuning capacitor of an externally tuned antennas can counteract each other.
This may be reduced by spacing the external tuned ferrite further away,
and moving it back and forth whilst optimising manual tuning. When the
externally tuned ferrite no longer "swamps" the internal varactor, a dual-tuned
input filter results, which can be effective. But adjustment can be fiddly.

Also, the chip varactor may not accommodate an out-of-range external inductor
which is directly connected to the receiver PCB. In some receivers, adjusting
the inductance (number of turns) of the external antenna can rectify this.
See the many postings re these external antennas.

The SONY-style short whip with pre-amp will work well on shortwave and
satisfactorily on MW and LW, but should be located outside to minimise RFI.
As always, efficient feeding of the signal into the receiver is critical for good results.

Where possible, the DIY approach is far cheaper - and eventually contentment
swamps any frustrations on the way !

Michael UK

----- Original Message -----
From: "farmerik" <farmerik@...>
To: <ultralightdx@...>
Sent: 27 July 2011 06:19
Subject: [ultralightdx] Re: Off the shelf amplified antennas for LW and AM BCB?


The SONY comes with an 'L' shaped base with the inductive coupler in it, which you lay your radio
against for AM and LW. In the photo it may show only the back of the 'L'. There is a curved rubber
pad for the radio to rest on the other side. It is made for use with portables.

I do have a Stormwise ferrite rod antenna in PVC which I bought already assembled from them. I tried
to tune it with a cap, and with the PL-360, but I couldn't get it to do much. It is about 18 inches
long. It probably does not have the correct winding, wire or ferrite mix inside I guess. The TERK,
SAT and Gary's two 7.5 inch ferrite's are all much better. I expect Kevin's design works very well
though.

-FARMERIK

--- In ultralightdx@..., Jerry Popiel <jerry_popiel@...> wrote:

Thanks Farmerik,yes we had an old Short Wave radio many years ago, and like you said reception
was as clear as a bell.

I agreewith you - I'd also like to find something Portablethat can be carried outside,is
light, & could be inductively coupled to my Tecsun PL 380, or G3 radios. Have you seen the
writeup of"The Monster Loopstick" by Kevin S/ Bainbridge Island, WA?Maybe one of those
Monster Stormwise 18 inch Ferrite Rod Antennas might work well for you?It is relatively Portable
in an 24 inch PVC Conduit.........BUT it requires some constructing & ordering of parts.But I
don't think it will help with Shortwave. I wonder how well it receiveson MW and LW?

Jerry

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