Noob question on touching antenna / other stations breaking through to SW band

[capa150]

Hello, I have been a radio listener (mostly FM, some AM) all my life. Just regular music and NPR and Coast-to-Coast. But I bought an XHDATA D-219 for shortwave and have picked up a couple stations from (I think) Australia and New Zealand. But I've noticed while scanning the bands that I can pick up the same station across wide swaths of a shortwave band. I think it might be a local AM station. It doesn't come in 100% clear but it's obviously the same person talking.

I've noticed that if I shorten the antenna (stock antenna) the problem can go away or be reduced. But then I wonder if I'm limiting my ability to pick up SW stations with the shorter antenna.

I've also noticed that if I touch the antenna with my hand that some of these problems can go away. Is this an appropriate thing to do or does it making picking up a signal harder to do?

Thanks!

Chris
Seattle WA

 

[vagrant]

What you are experiencing is not uncommon when a powerful broadcast station is nearby. An option would be to put AM and FM broadcast filters inline, or a combo filter, and use them with an external antenna. The filters will not work with your built-in telescoping antenna. Additionally, the external antenna should improve your overall reception for SW stations.

UPDATE: It appears that $10 radio does not have an external antenna port. Perhaps you could rig something by leaving the telescoping antenna collapsed and clipping something to the antenna and then running it through the filters and then to an external antenna. Ultimately it may not be worth it as the radio selectivity appears to be poor per your description.

 

[mmckenna]

Yeah, strong nearby AM broadcast stations will get into the receiver and overload/cause all kinds of mixing products that will result in it being heard all over the bands.
Shortening the antenna reduces the antenna performance and reduces the amount of signal that is getting into the radio (both the AM broadcast you don't want, as well as the shortwave you do what). You might find a sweet spot that works for you.
Touching the antenna is capacitively coupling your body to the antenna and adding to its length. That can help reception in some cases, make it worse in others.

That's the fun part with radio, you can experiment and see what works.
However, a $10 shortwave radio isn't goin got perform well in a high noise environment like Seattle. If it's doing what you want, then that's good. Taking it away from the city may give you some more enjoyment. Higher cost radios will perform better in the city, but you'll still likely have some issues.

 

[capa150]

Thanks!

 

[Boombox]

If your radio has a whip antenna you are using (I think the XHDATA 219 runs off of whip antenna for SW and FM), shorten the whip until the local station's interference recedes or goes away. If your radio is like my Grundig G2 (which may use similar, DSP chip circuitry), the Shortwave stations' signals may still come through with less local interference. The whip is overloading the radio because the local station's signal is so strong.

On my G2, sometimes I'll get overload from local AM band signals, which can interfere with the SW stations. I shorten the whip. Sometimes the G2 will work on SW with even just 6-8 inches of whip, and the local interference is gone, and the SW stations are still readable. Other times, I can extend the whip antenna out without any local AM interference at all.

So, try shortening the whip.

 

[bob550]

You could also try orienting the antenna on a horizontal plane instead of extending it vertically. Shortwave signals are generally horizontally polarized while AM Broadcast signals are vertically polarized. Doing so may null out the offending AM station to a degree. If you intend to connect an external wire antenna, try coiling the wire lead around the metal whip several times and make sure the antenna extends out on a horizontal plane as mentioned earlier. Just be aware that portables like these are designed to work with the built-in whip and an antenna designed to pull in more signals may just cause more overload.