Cobra 148GTL adding FM?

[cb4ever104]

Another option for the 148GTL is a DDS VFO kit!

To be honest you've saved me some grief , as I was going to try and fit mine into my 148 GTL as well I fitted one of Nick's "pics" into mine to make it 80ch . That's about all I've done to it . As you say €60 is just way too much for FM .

Cheers

[PeterA]

Another option for the 148GTL is a DDS VFO kit!

To be honest you've saved me some grief , as I was going to try and fit mine into my 148 GTL as well I fitted one of Nick's "pics" into mine to make it 80ch . That's about all I've done to it . As you say €60 is just way too much for FM .

Cheers

You can save the FM board and use it in something else instead...

Apparently the ddsvfo is a popular conversion for the 148GTL's over the pond...

[cb4ever104]

I think that spectrum module does work in the 148 GTL . The 148 , and the Madison , both have the additional 7.3450 crystal with the 455khz IF for AM , so I don't see why it wouldn't work . As I say . I've never fitted one in the 148 before , so maybe someone else can confirm .

[163TM847]

Spectrum FM 455 does work perfectly fine in a 148GTL [that has a 455IF], I have fitted many of them, BUT you will need to add a 10n cap across pins 2 and 7 of the 741 op amp.

[cb4ever104]

Hi Nick !

Many thanks for confirming that . I think the Spectrum guy got his radios mixed up . Also , thanks for the additional info on the 10n cap .

Sammy

[PeterA]

Spectrum FM 455 does work perfectly fine in a 148GTL [that has a 455IF], I have fitted many of them, BUT you will need to add a 10n cap across pins 2 and 7 of the 741 op amp.

Thanks for confirming it will actually work Nick, replied to your PM...

[Spider280]

I am glad I found this thread, but I was looking to do the same to add FM to the 148 GTL. I have the Spectrum FM455 board already and it has fitting instructions from him and included for PC-409 Grant, PC-411 Madison, PC-412 and PC-497 2000. Are these not going to work ?

I was also looking to add FM in the mode selector . Wondering if anyone has made it further. Especially heads or tails of a way to sort out the mode switch ?
I bought a 5 position ewrt32060s before looking at the connections and went of basic schematic switch layout and thought it could replace the ewrt32001s and have enough for FM switching by adding another waffer. Bo, I was wrong ! I don't know if those can be manipulated like the ss 3900 switch or if they just make a dual waffer version of that special ewrt32001s and I can give this mess a go !

[cb4ever104]

I am glad I found this thread, but I was looking to do the same to add FM to the 148 GTL. I have the Spectrum FM455 board already and it has fitting instructions from him and included for PC-409 Grant, PC-411 Madison, PC-412 and PC-497 2000. Are these not going to work ?

I was also looking to add FM in the mode selector . Wondering if anyone has made it further. Especially heads or tails of a way to sort out the mode switch ?

I was looking at this today . I have one of these spectrum boards and I was planning on sticking it in my Uniden Madison . BTW . The board will work in any 455 IF radio . To wire it on to the mode switch might be doable . I'll need to get the old pencil and paper out and see what needs to be done . The radio needs to be on "AM" for the FM RX part to work at least , so it might just need one more pole . I'll post back if I advance with it .

[cb4ever104]

In order to do this I think you might need a 4 position 4 pole switch . On "FM" you'll need to continue to switch in the 2 poles that are normally used on "AM" . On top of , you'll need 2 more new poles for the switching in of the new FM board . I'm not going to bother with all that hassle . I'm just going to use one of the front DPDT switches .

[electronicsmachine]

Spectrum FM 455 does work perfectly fine in a 148GTL [that has a 455IF], I have fitted many of them, BUT you will need to add a 10n cap across pins 2 and 7 of the 741 op amp.

I'm also interested, I have a Cobra 148GTL, but does the described FM card work perfectly...?

[Queball]

Check out the new Microchipz boards on Facebook or YouTube.

[cb4ever104]

Check out the new Microchipz boards on Facebook or YouTube.

Don't know if Graham does FM modules ? I bought a couple of his channel expansion pcbs which work great . He does a few VFO and beep ones too . I'll need to check for the FM ones .

[electronicsmachine]

Check out the new Microchipz boards on Facebook or YouTube.

Could you send me a link where I can look in detail...? Thanks

I'm interested because I have a Cobra 148GTL with AM/SSB

[cb4ever104]

I'm interested because I have a Cobra 148GTL with AM/SSB

I've got 2 148 GTLs , but no need for FM . Do a search on Facebook for "Microchipz"

I don't see any FM modules listed .

Capture.JPG

You can get one from Spectrum Communications (Google search it)

[163TM847]

Spectrum FM 455 does work perfectly fine in a 148GTL [that has a 455IF], I have fitted many of them, BUT you will need to add a 10n cap across pins 2 and 7 of the 741 op amp.

I'm also interested, I have a Cobra 148GTL, but does the described FM card work perfectly...?

He doesn’t do FM boards as far as I know, I have PLL boards for a wide range of PLL, The MB8719 board I have does -40 +40, U.K. Band, -5 and +10

They work with all mb8719 crystals with correct settings

15.480 (Mk1 148/30), 15.4825 (McKinley/Stalker), 15.4525 (Grant), 11.325, 11.1125

The 148GTL doesn’t always work on Low band, So 11.325 has to be swapped for an 11.1125