开云体育

Hello Ron,

A couple things here. The "1" in the last of the model number is 433 MHz not 443 MHz. I believe that with the shift method, or hex edit, will only let you go down in frequency, not up.

You also don't say what frequencies you are trying to use.

Mick - W7CAT

Howdy,

If the radio has the proper range just hold down o the shift key while typing in the frequency but let off the shift key when typing the middle decimal. The press shift again when you type in the reminder of the frequency after the decimal then hit TAB and your frequency should display correctly. If it will not accept those frequencies, it will tell you.

Hope this helps

73

DE KD5FMU

-- Fred "Freddie Mac" McGuire - KD5FMU Henryetta, OK

"If the radio has the proper range . . ."

Then there is no need to do anything but program it as you normally would. What he is trying to do is program some radios that are NOT in the proper range. And again, I don't think the shift method will work to bring the frequency higher.

Mick - W7CAT

They probably won't go. 440 is going to be pushing the upper limit, most likely.

For what it is worth, the frequency ranges for the GP300 (and P110) radios are as follows:
VHF
136-155MHz
146-174MHz
UHF
403-433MHz
438-470MHz
465-496Mhz
490-520Mhz

Using shift during frequency entering in RSS will allow for almost any entry, but radio specific VCO will only give you some leeway outside its own range, but not too much to operate well into the adjacent lower or higher ranges, specially for UHF models.

I've not done this in probably 25 years, so memory is a bit foggy, but don't recall the trick being effective only to go down in frequency, but rather also up. And what I do remember clearly is that it is very important that first of all you need to enter ALL frequency (7) digits (even if they are trailing zeros), and secondly it is also vital to remember to momentarily let go of the shift button when entering the period (.) into the frequency, otherwise in either case the RSS will reject the entry and revert to displaying the previous frequency.

Also probably worth mentioning is that since the VCO voltage also controls the adjustment/tracking of the RX stages, its important for that to work right, as depending on the target frequency you may still have a decent VCO lock but the receiver sensitivity might not be very usable.

Mainly as a test and mostly for the fun of it in the mid-late 90s was able to convert a 490-520 unit down to the 438-470 range by replacing parts taken from a carcass radio which consisted of over half a dozen low value (pF) tiny 0406 SMD chip caps mainly from the receiver stages and VCO, and possibly at a couple of other spots, plus having to swap the transmit power module, and then use the shift entry to program it. But in the end had somewhat limited success, as the radio basically worked but there where still some deficiencies and it would also not work properly for the whole intended new lower range. Maybe there where a few other caps that I missed, and in the end this non trivial procedure was barely worth the effort, but it proved that a range conversion was possible.

Hope that helps some.