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Ideas for AM, NB FM Demod and CW filter board

 

FM is used on 29 Mhz!

Raj


At 05-06-18, you wrote:
Hello

Questions to ask:
Is the AM still used at amateur radio level
Is the FM used in the HAM band, except that the uBitx attacks a 144 or 430mhz transverter?

73

2018-06-05 12:44 GMT+02:00 <tutdavid@...>:
Hi,Â

Yes I think this would be a great improvement to implement also AM/FM to the uBITX.Â

Does anyone have some ideas ?

Thanks !

F1BFU - Fr - 79
 

Yes that is true but we must not forget that Bitx and uBitx are affordable for a beginner amateur radio and that adding a lot of additional features will confuse more than one if the price was a lot most important.
What makes Bitx interesting is the price that allows a beginner to start and a seasoned enthusiast to experiment with many things. We are still in the QRP traffic domain.
Or we must add these features in the form of additional cards that can be purchased or manufactured later.
I think the most desirable goal would be to make a modular package that everyone can change as they see fit.

That's just my opinion
73 QRO

2018-06-05 13:03 GMT+02:00 Radu <radu.loga@...>:

@Gilles,

Lets not forget that in some countries HF equipment is quite expensive and therefore many of the new radio enthusiasts are starting in CB 27Mhz AM/FM.
In my opinion this modes are also quite useful.
Also on amateur radio level in 10 meter band in the summer when the propagation is open many nice QSOs can be made in FM around 29600Mhz.
So in these case why not to have AM/FM


Tim Gorman
 

For AM you would have to derate the power output from the ubitx to
about 2 watts on 80m. 2 watts on 80m would translate to about 250mw on
10m. Is that enough output for what you want?

Even narrow-band FM on the ham bands are incompatible with the 12hz SSB
filter in the ubitx. That affects both receive and transmit. And FM
power output would have to be derated just like AM.

It would be easier to design an am/fm rig from the ground up, perhaps
using the Radiuno.

tim ab0wr


On Tue, 05 Jun 2018 03:44:09 -0700
@dr.David wrote:

Hi, 

Yes I think this would be a great improvement to implement also AM/FM
to the uBITX. 

Does anyone have some ideas ?

Thanks !

Arv Evans
 

And....the modified design would no longer be a BITX.
There are other low power designs out there in kit or homebrewed form that would be much
easier to modify for FM and/or AM. 

http://www.sp5ddj.pl/taurusdziennik.htm

http://www.glcharvat.com/Dr._Gregory_L._Charvat_Projects/6_%26_10m_SSB_CW

It would seem more productive to work toward an LF mod for the BITX and uBITX
designs.  LF might be more of a challenge due to antenna requirements but should be
easier to do the circuit modifications that are required.

Arv K7HKL
_._


On Tue, Jun 5, 2018 at 11:14 AM Tim Gorman <tgorman2@...> wrote:
For AM you would have to derate the power output from the ubitx to
about 2 watts on 80m. 2 watts on 80m would translate to about 250mw on
10m. Is that enough output for what you want?

Even narrow-band FM on the ham bands are incompatible with the 12hz SSB
filter in the ubitx. That affects both receive and transmit. And FM
power output would have to be derated just like AM.

It would be easier to design an am/fm rig from the ground up, perhaps
using the Radiuno.

tim ab0wr


On Tue, 05 Jun 2018 03:44:09 -0700
tutdavid@... wrote:

> Hi, 
>
> Yes I think this would be a great improvement to implement also AM/FM
> to the uBITX. 
>
> Does anyone have some ideas ?
>
> Thanks !




g8tdu
 

I have in fact created a FaceBook group to investigate the possibility of adding AM/FM to the uBITX and the older BITX. This group has attracted 120 members in less than 24 hours.!

I have had a few chats with Ashhar on this and he suggested using the IF frequency of 45Mhz. This limited the choice of IC's which would work at 45Mhz AM, the TDA1220 will work at this IF frequency. Kyocera make some nice 12.5Khz 6 pole filters which should work nicely with this IC.

In addition we also want to add CTCSS to the board for repeater use. Most of my VHF/UHF and above equipment is done via transverters, and i wanted FM especially for repeater use.

The new group dedicated to just this can be found here.... https://www.facebook.com/groups/2517941545160596/

g8tdu
 

It would still be a uBITX but with an add on board

g8tdu
 

I have also searched for IC's to add AM/FM and narrowed it down to the same TDA1220 IC you have. Ashhar suggested working from the 45Mhz IF frequency and this is one of the very few that will work with AM at 45Mhz

jim
 

Thot about trying this for an AM detector....

On Friday, January 3, 2020, 5:28:42 AM UTC, g8tdu <jomac_uk@...> wrote:


I have also searched for IC's to add AM/FM and narrowed it down to the same TDA1220 IC you have. Ashhar suggested working from the 45Mhz IF frequency and this is one of the very few that will work with AM at 45Mhz

Jens / DH1AKY
 

Ralph, ku4pt wrote:

  the other is to drive some VHF/UHF converters from the Ukrain that are selling for less than $ 100.  
Same as me, but I've not built my V4 until now. So I use a Multus Proficio SDR for driving the transverters. Works as expected, used that setup during Marconi VHF contest, well done.

The Proficio is an excellent QRP rig from 160m to 10m. On outdoor use I would prefer the uBitx.

73s, Jens/DH1AKY