Why no UHF on walkman radios?

Factual Questions
1

I’ve been looking for a walkman-type radio that can get UHF. All the ones I’ve seen have AM, FM and VHF only. Why is it so hard to make a walkman that has UHF. I realize FM comes between Channels 6 and 7 in reality, but is there something cost prohibative against putting UHF on a walkman?

I’ve seen little TV’s at Walgrees for $19.99 and online I did find walkman type radios with UHF for almost $100.00. Which seems excessive especially since in two years they won’t work anyway when we switch to digital TV.

So what is the reason they don’t put the UHF band on walkmans?

2

It costs more money. You are asking for a major increase in the frequency coverage of the radio. In general, the higher the frequency, the more expensive it is to design and build a receiver. The UHF band is large enough that it would be tricky to design an analog tuning control that would be easy to use and stable.

3

Television audio is the FM band - or a part of it actually. It may be that particular part of the spectrum is only covered by some typically non-standard chip that costs .06 instead of .01

4

It’s because you’d need four or five seperate receivers instead of one.

Look at the chart (scroll down) here:

Channel 2 starts at 54MHz. Channel 13 is at 211.25 MHz. In between there are all the VHF channels and the FM broadcast band (88-108 MHz). That spread could be accomplished with one receiver.

Then go to UHF. Channel 14 - at 471.25Mhz! Quite a jump, huh? In between Channel 13 and 14 is over 250MHz of space, occupied by commercial two-way, government users, amateurs, and military.

Now jump up to Channel 69 (and no jokes about that channel, please…). 801.25MHz!

For you to cover that space with a small handheld radio, you’d need probably four seperate receiver units. One to cover 54-205MHz, one for 470-512MHz, one for 513-650MHz, and one for 650-802MHz. These numbers may not be exact, but I’m going by my previous two-way radio experience to estimate those figures.

TVs have the space for large receiver units while small units don’t have that luxury.

Clear as mud?

5

IANARadio designer, but I don’t believe the width of the electromagnetic spectrum covered translates directly into a physical size of the unit. Look at shortwaves with multiple bands. The frequencies are synthesized nowadays – were you expecting a giant variable capacitor?

6

It doesn’t have to be large. See the ICOM IC-R5 for an example of a modern wideband receiver.

http://www.icomamerica.com/products/receivers/r5/

It isn’t going to be cheap.

7

Well, in our two-way business, we had the following:

VHF radio - 136-174 MHz.

UHF radio: 440-470MHz, 470-490 MHz, or 490-512 MHz.

On the other hand, we had service monitors in the bay that would cover from 100 kHz to 1.5 GHz.

But the radios usually cost between 400-600 dollars while each service monitor cost $10,000 - $15,000.

Circuits can be designed to do just about anything you want - depending on how much you want to pay.