Wire Basic Receive Only Long-Wire Ant. Questions

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ka3jjz

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Bob if you don't feel the radio is performing up to par, you should return it. It's certainly possible you got a bad one- production errors happen. We have a thread on your radio in another forum that kinda suggests this, since it seems to be performing well for others

Mike
 

WA8ZTZ

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Bob,

IMHO, you are going to worry yourself too much by over analyzing this antenna thing.
The radio is a portable with apparently no provision for external antennas (ie-- antenna jacks).
It is what it is.
Even if the radio had provision for an external antenna(s), no one antenna would be effective for all bands AM, FM, SW, VHF.
Reception may be poor indoors for a number of reasons but since it is a portable it can be taken outdoors (your backyard, a park) where reception will probably be better.

Hopefully you will find a way to enjoy your new radio.
 

MUTNAV

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For MW and probably shortwave there are some sites that describe how to either make an external antenna jack if that is the route you want to go.

peditio.net/utility/pdf/Adding_a_MW_Antenna_Port_to_Tecsun%2520DSP_Ultralights.pdf

or you could try this.

peditio.net/utility/pdf/Antenna_Couplers.pdf

There is also the SM-100 (signal magnet 100) no longer being made, by Ramsey electronics, the concepts to it could be used with a better low noise amplifier.

or you could try an "AMRAD" amplified short whip antenna.
or
You could try a "carpet loop" (already mentioned)


There are two different designs for an interference reducing antenna (actually designed to reduce jamming), for international shortwave radios. They are designed for inside use and simple construction by people in USSR and China etc. for people to receive VOA broadcasts over state sponsored jammming.

one of them is.
Magic Anti-Jamming antenna - IW5EDI Simone - Ham-Radio

There is another one out there, I just cant find it.

This seems to be a fairly good loop arrangement.

https://www.randombio.com/loopantenna.html

You basically have all kinds of options to help out your reception.
In addition to hunting down noise in your house and fixing it.

Good luck
Let is know what happens

Joel
 

nanZor

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Hi Bob - maybe this will help ...

In my excitement to test the 23 foot reel-up, the first thing I did was hook it up backwards. That is, I clamped on the clip that serves as a mounting clip with no connections inside it, and reeled it out the wrong way where the clip actually has metallic fingers inside. Swapped the clips around the right way, and bingo.

Hey, it happens to the best of us. :)

For this type of ultra small radio, we don't over-analyze the antenna. The major objective is to just get it away from noise and close to being outside.

The reel-up can be made into any number of makeshift shapes for this application. Up and over something, made into a circle or square around a window, not even fully reeled out either. Temporary positioning can be done quickly with blue painters-tape so you don't mar any surfaces.

Throw it simply on the floor reeled out? Sure - it *might* be enough to provide a good signal-to-noise although directionality is not the major concern. Experiment. Reel it away from your operating position to somewhere else in the house.

Interestingly enough, simply thrown on the floor clipped to the radio may be *enough* to allow for even vhf airband and fm reception. Again, predicting directionality, impedance and so forth is obviously not the primary thought - just getting enough signal away from your indoor noise sources is.

This is classic old-timey stuff. Run the wire down along your baseboards etc. Too noisy? Change it.

More advanced uses might be to carry along just a small 3 foot jumper of wire, and inductively / capacitively couple it to an existing structure for kicks. Ie, wrap a bunch of turns around the *collapsed* whip, and with the small pigtail left, just place it next to something metallic. Maybe use the blue-tape method. At the ballpark and wonder if inductively coupling to a safety railing might work? Try it. You'd get thrown out if you stretched out the 23 foot reel. :)

For more AM BCB stuff, perhaps you'd like to try one of the small BCB loops that inductively couple to small radios like this - like the TERK or Grundig AN200 where you simply place the radio near the loop and tweak and turn it and have fun that way. That's a pretty potent portable combo at the picnic table.

It's a palm-sized portable radio that wants to be outside, but with indoor noise, it calls for experimentation, rather than ideal antenna engineering.

Hmmm.... how about clipping a jumper to the center conductor of your discone, and wrapping a few turns of the jumper around the collapsed antenna? Yes, you probably could make a direct connection to the whip with the jumper, but I'd recommend trying the "wrap a bunch of turns around the whip" idea first.

Super directionality, impedance matching and so forth are not the major concern. Just experiment to get the best signal to noise with this type of radio if one can't get outside.

The neat thing about the CCrane Skywaves without an external antenna jack is that is provides a necessary break for those of us who live behind computer modeling screens and wonder "lets clip this around a shopping cart handle and see what happens." As long as we don't over-analyze it, it can be a load of fun.
 
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ka3jjz

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One thing to be careful of here - watch out for any static discharges. Don't touch the whip with a static zap - it will likely render the radio deaf. It's very likely that there is one or more amps at or near the antenna base.

Mike
 

Boombox

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Hi All,

Thanks for help with this.

Will have to dig out my (very) old books on antenna theory and try to get into again.
Interesting subject, as it always seems to combine "theory" and a bit of black magic.

Appreciate the help, very much.

Regarding running a simple wire around the 4 walls at the ceiling of my room:

Is there anything likely to be gained by doing it a few times (multiple loops) ?

And, my previous question re how a simple long wire can be used for vhf and stuff >30 MHz ?
Any thoughts and wisdom on this ?

Thanks,
Bob

Multiple loops may or may not help. Try just running a wire around the ceiling and see how that works.

Any outside antenna -- especially in areas where there is lightning, or any area of the US during winter -- can produce static discharges that can zap a radio's RF amps. Some radios have internal protection. I do not know if CCranes have it or not. So try an indoor wire, on an outside facing wall. See if that helps.
 

nanZor

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Re the static zap: Makes sense not to zap the antenna, especially during winter conditions.

I zapped my CCrane SSB to the point where I just needed to power-cycle the radio to get audio back.

What astounds me is that radios using the SiLabs chips basically have a direct connection to the chips own on-board lna, rather than any intervening front end amp. Well at least as far as I can tell from the Silabs spec sheets and circuit block diagrams.

https://www.silabs.com/products/audio-and-radio/multi-band-radios

Considering that these chips are basically the lower power AA-driven versions of the vehicle mobile equivalents, I'm amazed that chips don't just blow up from static in either application.

Although as I've experienced with some other manufacturers, just having a SiLabs chip on board does not automatically mean a manufacturer is making the best use of it. :)
 

w2xq

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Bob, you are overthinking trying to put an antenna on the portable radio. If the whip isn't collecting enough HF signals, attach the reel antenna or equivalent length of hookup wire. You don't even need a clip; shorten the whip and just wrap a couple turns around it. No antenna theory books, no formulas, or anything you are worrying about. Relax.
 

Boombox

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Re the static zap: Makes sense not to zap the antenna, especially during winter conditions.

I zapped my CCrane SSB to the point where I just needed to power-cycle the radio to get audio back.

What astounds me is that radios using the SiLabs chips basically have a direct connection to the chips own on-board lna, rather than any intervening front end amp. Well at least as far as I can tell from the Silabs spec sheets and circuit block diagrams.

https://www.silabs.com/products/audio-and-radio/multi-band-radios

Considering that these chips are basically the lower power AA-driven versions of the vehicle mobile equivalents, I'm amazed that chips don't just blow up from static in either application.

Although as I've experienced with some other manufacturers, just having a SiLabs chip on board does not automatically mean a manufacturer is making the best use of it. :)

You're apparently just going by the SiLabs chip application data -- the actual radio used may or may not have diode protection at the antenna. That would be something that would best be determined by looking at the PCB of the radio in question, or a schematic of the radio.

In my case, I know the Sangean PR-D5 (which in models after 2012 uses a SiLabs chip) has internal diode protection, something I discovered by looking at a schematic.
 
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