Old VS Newer SW Radio's

[SCPD]

OK, I have a realistic DX-342 single conversion SW radio with analog, just picked it up on CL today.

Also have a Grundig Satellit 500 and YB 500 Both dual conversion with digital readouts.

Now how come I am picking up A LOT more stations on the Realistic than the 2 grundigs, is single conversion more sensitive?

I am just using the built in whips on all radio's and same location.

and all are running off of batteries, all batteries are new.

it's funny tho, with my sanyo rp-8880 single conversion SW radio picked up everything but when I bought my Grundig satellit, 1991, i noticed a difference...

any thoughts?

 

[majoco]

Are you sure that all the stations you are hearing are in the right places on the dial?

Single conversion radios suffer from what officially is called 'image interference' and usually called 'double spotting' - double conversion receivers don't have this defect.

What happens is that you will hear the same sation twice, one may be weaker then the other, at twice the IF frequency apart. Most radios of that 'quality' have an IF frequency of around 455kHz, so you will hear the image about 910kHz away. A better radio will have a tuned RF amplifier stage which will reduce the image, but double conversion is the best.

Double conversion radio have another first IF above the highest frequency, previously about 45MHz but later radio's are up in the 70MHz area. Thus the 'image' is so far away as to be untunable. Then there is a fixed frquency oscillator to transfer the high frequency IF to the lower one.

 

[K9WG]

Probably has more to do with the front end amplification and filtering.

 

[kb2vxa]

The Realistic DX line is notorious for IF images.

 

[SCPD]

Believe it or not I was listening to my DX-342 and my YB500, tuning the DX to stations then tuning them on the YB and I do not hear images on the DX.

The little DX seems like a nice radio.

The batteries last long, I've been using it since I bought it non stop and I've had a eton s350 and that thing had images all over, not on the DX-342.

So now I use the DX in conjunction with my yB500.

it is sensitive radio.