BCD396XT/BCD996XT: Bring your 3/996XT into the 21st century :)

[Mike_G_D]

CFWKA450KGFA-R0 was the original 50G filter in the modification and it contains six ceramic elements. The CFUCG450F contains only four ceramic elements and that is why it is smaller. It will have inferior attenuation outside the passband. Is a CFUCG450F better than the stock filter, CFWKA450KEFA? I'm not so sure it is. Better to use a CFWKA450KFFA available at Mouser.

I agree - you don't want to go with fewer elements for performance reasons as well as the obvious pcb landing footprint!

For me, when I get around to it, I think I will still go for the tighter G filter as my only affected unit is an analog only BCT15 and I only use it for NFM signals and occasional air AM. It will make it FAR AND AWAY more useful for me as I have a lot of local CDF traffic that uses closely spaced channels which, with the stock filter, are nearly impossible to deal with (hear two or three adjacent channels simultaneously!). If I can get some other things under control first I will surely be performing this mod in the future!

But for others, who may be listening to a a lot of P25 stuff and maybe not so much NFM analog, the F filter 6 element equivalent, CFWKA450KFFA, might indeed be the better choice.

Interesting to note, though, that the original stock filter as well as the F version have a 3dB quoted ripple in the passband as opposed to the 2.0dB quoted ripple in the passband of the G version. Not really a major issue for analog FM and maybe even C4FM P25 but could be problematic for more intolerant CQPSK signals; this may be why many are seeing some major improvement in some P25 systems when using the G version (a reason besides simply tighter bandwidth).

-Mike

 

[KD4UXQ]

CFWKA450KGFA-R0 was the original 50G filter in the modification and it contains six ceramic elements. The CFUCG450F contains only four ceramic elements and that is why it is smaller. It will have inferior attenuation outside the passband. Is a CFUCG450F better than the stock filter, CFWKA450KEFA? I'm not so sure it is. Better to use a CFWKA450KFFA available at Mouser.

Good info. Thanks for the link on Mouser.

Being that the G filter is not available on Mouser and seems to not be anywhere else, I'm going to order the F filters CFWKA450KFFA from mouser at $7.77 each and try them. As far as replacing them, what has your experience been with how difficult it is to lift them off the PCB? I'll have to use a sharp pointed pencil iron and use light pressure to lift it off.

 

[kruser]

Good info. Thanks for the link on Mouser.

Being that the G filter is not available on Mouser and seems to not be anywhere else, I'm going to order the F filters CFWKA450KFFA from mouser at $7.77 each and try them. As far as replacing them, what has your experience been with how difficult it is to lift them off the PCB? I'll have to use a sharp pointed pencil iron and use light pressure to lift it off.

It's not bad at all. I only had issues on the first radio I did. I was not heating the grounded side enough due to the amount of copper under those two leads. I ended up pulling one of the leads out of the original filter when I thought it had released from the board.

I changed my tip for a beefier tip for the other 7 or so I swapped out and that worked fine.
I think my iron is a 40 watt but has temp adjustments and I don't recall what temp setting I'd used.
The leads coming out of the filter appear to be fragile as I hardly had any pressure on it when I thought it had melted enough to lift it away.
The two active leads lift off very easy with low and a short amount of heat so be careful with those two if you plan on salvaging them in case they need to go back in.

I used a dental pick on some but most were tight to the board so I used a razor knife blade to get under the first edge.
I did not want to ruin the original filters just in case of unfound negatives.
The new G filters are all still in all my radios now and I have all but one of the originals in the parts bin just in case a problem does surface.

I may try some of the F filters in a couple of the radios just to see how the do side by side with the narrower G filters on some of the wide bandwidth signals still on the air around me.
Honestly though, the G filters seem fine and the only thing I found is the need for the higher squelch setting on some of the analog stuff I still monitor.

 

[KD4UXQ]

It's not bad at all. I only had issues on the first radio I did. I was not heating the grounded side enough due to the amount of copper under those two leads. I ended up pulling one of the leads out of the original filter when I thought it had released from the board.

I changed my tip for a beefier tip for the other 7 or so I swapped out and that worked fine.
I think my iron is a 40 watt but has temp adjustments and I don't recall what temp setting I'd used.
The leads coming out of the filter appear to be fragile as I hardly had any pressure on it when I thought it had melted enough to lift it away.
The two active leads lift off very easy with low and a short amount of heat so be careful with those two if you plan on salvaging them in case they need to go back in.

I used a dental pick on some but most were tight to the board so I used a razor knife blade to get under the first edge.
I did not want to ruin the original filters just in case of unfound negatives.
The new G filters are all still in all my radios now and I have all but one of the originals in the parts bin just in case a problem does surface.

I may try some of the F filters in a couple of the radios just to see how the do side by side with the narrower G filters on some of the wide bandwidth signals still on the air around me.
Honestly though, the G filters seem fine and the only thing I found is the need for the higher squelch setting on some of the analog stuff I still monitor.

Thanks much for the detail on your experience with changing these out. It looked simple enough, but of course I cannot see the size of the pads under the filter and would have had no idea the leads on the filter were so fragile. This helps a lot.

 

[Forts]

I just recently re-acquired a 396XT and would love to perform this mod... So I might as well throw my hat into the 'if anyone has an extra' pile....

Sent from my One using Tapatalk

 

[urdumb]

anyone have a source for these? I'm looking for two.

 

[mrkelso]

I still need one

 

[stmills]

I could use 1 if anyone had one

 

[pro106import]

delete

 

[AronDouglas]

Bookmarked for the upcoming 996XT I'll hopefully be getting for Christmas

 

[kd7ckq]

Anyone have a spare G filter or two?

 

[wa2sqq]

For those of you who work in the communications or consumer electronics industry, here's how you can get your G filters. I have five radios that use this type filter. I contacted Murata and requested 5 samples. Got a call from the rep who verified the sample request and employer. I had the samples (@ no charge) in 1 week. Two are already installed and working OK. Don't get greedy, just request what you need, and DO NOT try this unless you actually work for a company who might order them.

 

[kruser]

I had to revert back to the stock E filters.

I first noticed I'd lost reception of two local VHF P25 Moswin sites in my area. No lock to the control channel at all.
Replacing the G filters with the stock E filters one radio at a time restored the CC signals just fine.

It's kind of a bummer as the G filters did help on the 7/800 MHz P25 sites I monitor.

I also noticed no more reception of the distant VHF MOSWIN control channels that I could get with the E filters.

The odd thing is I received all these VHF sites just fine when I first installed the G filters but something changed with time.

So far, I've reverted back to the E filters on my 996T, XT and 396XT but not the HP1 which I don't use often.

I'm working on a way to electronically switch the G and E depending on band so I can still have both but not sure if that is feasable or not.

There is also an IF can or transformer right next to the Murata filter. I can coax a CC lock when I place a ferrous metal object into the tuning slug so I suspect the radios may work fine with the G filters with a simple alignment but Uniden has poured some type of clear fastener in the cans making adjustment impossible.

I'll replace one of the cans if I can figure them out and source them. I tried heating whatever they added in after adjustment but no luck getting the tuning slug to turn.
Most companies just add a wax so retuning can be done after components age.
It's possible software tuning could be done at that stage also but I doubt we will ever see that software or needed interface info unless it's built into a hidden menu.

edit: I should also add that I left one of the 6 pole F filters from Mouser in one 996XT. That radio also has problems locking to the control channel of the VHF sites in question but it does at least obtain a lock and then usually keeps it even after voice traffic has steered away from the CC signal. It just takes a few minutes before it obtains a CC lock. The radios with the G filters would also obtain a CC lock but they usually needed to be powered on for 30 minutes or longer.
Going back to the E filter results in an instant CC lock on all that I reverted back to the stock filter.
The Moswin system is built on mostly single site non-simulcast VHF sites and those are the ones giving me issues with the G and even F filters.
The 7 or 800 MHz sites are fine regardless of E,F or G filters.

 

[jland138]

Sorry to hear the mod didn't work out. We don't have P25 trunked VHF here, but it sounds like the VHF receiver isn't quite on frequency. If you're able to do a SINAD test, you could compare your numbers to the ones Boatanchor posted back in April. While you have it set up for SINAD, rock the frequency a few kHz on either side and verify that the drop-off on each side is nearly symmetric.

Honestly, I wouldn't turn any slug on a radio that didn't come with a complete schematic. But, maybe you have better ears, test equipment or faith in God than I do.

 

[bbtkd]

Any of the Murata CFWKA450KGFA-R0 filters still available?

 

[XTS3000]

If you have a junk Waris (HT750/1250), that radio contains the narrow filter you need for the 396XT.

This part is also available from Motorola (not sure the part #)