how to improve antenna for portable radio?

[wenzeslaus]

I sure would like to attach a 100 foot EFHW to my battery powered SW radio. but I can't. all it has is a telescopic antenna. no jack.

what can I do that's better than just a 100 foot long wire attached to the antenna?

 

[LCRay]

Never mind. Was going to suggest clipping wire to antenna as that should give you a lot of improved signal.

 

[mmckenna]

I sure would like to attach a 100 foot EFHW to my battery powered SW radio. but I can't. all it has is a telescopic antenna. no jack.

what can I do that's better than just a 100 foot long wire attached to the antenna?

Never used one of these, but it might be an option:

Twin Coil Ferrite® AM Antenna Signal Booster

C. Crane offers the ideal AM radio signal booster antenna for improving most AM radio reception problems. Click here to improve your AM reception.

ccrane.com

One of these loop antennas can boost performance and does not require direct connection to the radio:

Antenna Pulls In AM Stations

While we can’t argue that FM has superior audio quality and digital streaming allows even higher quality in addition to worldwide access, there’s still something magic about hearing a w…

hackaday.com

Usually you want to be cautious about connecting a really long wire to the telescopic antenna. The longer wire will result in more static electricity meeting the soft/delicate bits inside the radio and can sometimes result in damage. Might work fine for some, might not work well for others.

 

[spongella]

Very good question. You might have problems with signal overload on the shortwave and AM broadcast bands. . Why not try a shorter, 30 foot wire antenna, strung outside just for an initial test? Also, knowing what receiver you are using will help.

 

[wenzeslaus]

Never used one of these, but it might be an option:

Twin Coil Ferrite® AM Antenna Signal Booster

C. Crane offers the ideal AM radio signal booster antenna for improving most AM radio reception problems. Click here to improve your AM reception.

ccrane.com

One of these loop antennas can boost performance and does not require direct connection to the radio:

Antenna Pulls In AM Stations

While we can’t argue that FM has superior audio quality and digital streaming allows even higher quality in addition to worldwide access, there’s still something magic about hearing a w…

hackaday.com

Usually you want to be cautious about connecting a really long wire to the telescopic antenna. The longer wire will result in more static electricity meeting the soft/delicate bits inside the radio and can sometimes result in damage. Might work fine for some, might not work well for others.

how are those going to receive shortwave?

 

[wenzeslaus]

Very good question. You might have problems with signal overload on the shortwave and AM broadcast bands. . Why not try a shorter, 30 foot wire antenna, strung outside just for an initial test? Also, knowing what receiver you are using will help.

because I want to do better than just a long wire.

any one of the battery powered SW radios. I have several right now and possibly others in the future. how about a Sony SW11 for example.

 

[WA8ZTZ]

Never used one of these, but it might be an option:

Twin Coil Ferrite® AM Antenna Signal Booster

C. Crane offers the ideal AM radio signal booster antenna for improving most AM radio reception problems. Click here to improve your AM reception.

ccrane.com

This antenna will wake up any portable AM radio and really pull in the DX.
However, the OP mentioned a "battery powered SW radio" (portable).
It is not intended for use on the SW bands.

IMHO, if you are really serious about SW DXing, get a tabletop receiver.
The portable is what it is... a portable. It is fine for casual listening on the go.
If you want to do better than "just a long wire", realize that an elaborate antenna system
defeats the portability and may also overload the portable.
Portables generally have adequate sensitivity but lack selectivity and dynamic range.
Therefore, get a real communications receiver and an appropriate antenna
system to do it right if you want to chase the DX.

 

[mmckenna]

This antenna will wake up any portable AM radio and really pull in the DX.
However, the OP mentioned a "battery powered SW radio" (portable).
It is not intended for use on the SW bands.

You are absolutely right. At the time I was typing that, I was listening to AM DX and looking online at GE Super Radios. Had AMBCB DX on my brain.

 

[WA8ZTZ]

You are absolutely right. At the time I was typing that, I was listening to AM DX and looking online at GE Super Radios. Had AMBCB DX on my brain.

If you are into AMBCB DX, consider getting one of these CCrane Twin Coils Antennas. It had been gone for a while but now looks to be
available again.
The Twin Coil AM antenna will inductively couple to an AM portable and greatly improve reception.
You will hear signals that you otherwise wouldn't know were there.
It will not improve reception as much on a higher end AM portable (Superadio) as on, say, a pocket portable,
but you will notice an improvement on any radio. The key is being able to rotate the antenna portion to peak/null a signal.
It does not have to be installed outdoors. Mine works great in the basement.
btw... the Superadio III has excellent audio and provision for an external antenna and ground although the nearly 8" ferrite does
a good job on its own. The only drawback is that the top end of the scale is quite compressed and the tuning there seems touchy.

 

[mmckenna]

Yeah, I built my own many years ago.

As for the Superradio, the prices get a little silly on e-Bay. I need to find one locally from someone who doesn't think it's made of gold.

 

[Boombox]

The amount of wire a portable SW radio will handle depends on the individual radio. Many portables will overload with 100 ft of wire, whether clipped to the antenna, or even if you connect it to the radio via an EXT antenna jack. YMMV.

Just use the longest wire antenna that the radio will handle. There are also antenna tuners, outboard preselectors, that sort of thing, that might help match the wire to the radio that only has a whip antenna.

Lastly, there is the proximity effect. You can couple a small portable to a long antenna by locating the radio near the end of the wire, or the antenna feedline, without a direct connection. The radio can pick up the antenna's re-radiated signal via induction.

Sometimes placing the whip near the feedline or the end of the wire -- without touching it to the wire -- will improve reception. I did this with a Radio Shack portable in the 1990s and got decent results (the radio was the DX-370, a portable with no EXT antenna jack). I was able to hear Tunisia with it, and I'm in the NW US.

 

[Boombox]

Yeah, I built my own many years ago.

As for the Superradio, the prices get a little silly on e-Bay. I need to find one locally from someone who doesn't think it's made of gold.

Check thrift stores periodically. Sometimes SR's show up there.

 

[majoco]

Anythings portable if it runs on batteries and has a handle........

 

[MUTNAV]

If you insist on using a long wire, dont just consider the static aspect (a high value resister to ground should help with that), but also consider an attenuator, it doesn't have to be specifically labeled as an attenuator, a variable resister would work, that would give you a chance of dealing with overload.

End state wise, picking up lots of signal may not be the big problem, the big problem may be picking up just the signals you want, in which case consider just "narrowing" everything, as appropriate, until you are happy.

Narrow beam-width (horizontally), Narrow Bandwidth, and narrow beam width (vertically).

Good luck, and let us know how any experiments turn out (the more negative the results the more helpful and interesting / it is)

Thanks
Joel

 

[MUTNAV]

This antenna will wake up any portable AM radio and really pull in the DX.
However, the OP mentioned a "battery powered SW radio" (portable).
It is not intended for use on the SW bands.

IMHO, if you are really serious about SW DXing, get a tabletop receiver.
The portable is what it is... a portable. It is fine for casual listening on the go.
If you want to do better than "just a long wire", realize that an elaborate antenna system
defeats the portability and may also overload the portable.
Portables generally have adequate sensitivity but lack selectivity and dynamic range.
Therefore, get a real communications receiver and an appropriate antenna
system to do it right if you want to chase the DX.

There aren't a whole lot of new shortwave tabletop receivers on the market, there are some, and of course there are lots of used ones.

If I were to go this route and only consider a new radio, I would consider a ham radio with wide band receiver.

The portable recievers sure seem to get good reviews.

It would help a lot if the OP mentioned which portable radio he has.

Thanks
Joel

 

[ka3jjz]

There are a few el cheapo Chinese models that don't have an external antenna jack, but you can try this - it uses induction to couple energy via the whip

If you're just using a typical inverted L design (a lot of beginners use this as a good starter antenna), take the wire lead in and wrap it around the bottom (not the base) of the whip. Around 6-8 turns should be all you need, but this will take some tweaking to see what works best. Then ground the wire lead in. It's crude but you should be able to couple some of the RF coming down the wire without you actually touching the whip. Touching the whip with static electricity around will likely blow the amplifier, rendering the radio deaf as a post. This method avoids that entirely

Mike

 

[wenzeslaus]

Good luck, and let us know how any experiments turn out (the more negative the results the more helpful and interesting / it is)

Thanks
Joel

results in another topic

random wire length survey

 

[MUTNAV]

Now we just need to know what kind of radio..... Especially since some radios have "hidden" features that allow for the switching of antenna inputs.

Thanks
Joel

 

[BMDaug]

I broke down and bought a Malahit DSP2… it’ll do USB, LSB, DSB, AM, FMW (in stereo), FMN, and will also decode CW… there’s also an FT8 and a RTTY function, but I haven’t played with that. It’s SDR based, so you get a touchscreen waterfall that you can use to ‘snipe’ signals… if you see it, tap there and the radio tunes. You also get adjustable noise cancellation, 5ah usb rechargeable battery, TWO SMA PORTS, one 50ohm and one hi-z, and you can plug it into a computer and use it as an SDR. It has a bias T so you can use active antennas too!

It’s about as portable as you can get. 4”x6” and comes with a padded case. I don’t have any affiliation with the designer, it’s just a product I’m excited about!

-B

Edit: left off the part where I say that I’ve been there and have had the same issues (hence why I ‘broke down and bought’ the DSP2)… I’ll also mention that the old Zenith radios had a variety of antennas and antenna connections, some hidden in the back panel, so yes, knowing the radio model can help folks recommend solutions.