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lower the better ...10 Meters . That might be true if you ignore the ambient noise floor. But it is also true that at the lower frequencies, the more QRM you have (and it is getting worse). The old GE noise blanker used to take care of a fair amount of this, but today's transceivers (FM, that is) p...

g8tzl2004 wrote:Is the Larson MNO50 also a 5/8 on 2m? ie it is a loaded 1/4 wave and not a full length 1/4 wave?

I am not sure. I have always run two antennas, one dual band for 2/70, one for 6 meters. Currently 10+ years on the current setup. I never tried to load the NMO50 on 2 meters.

John
AA4TX

I am not sure what kind of terrain you are dealing with (it does matter a lot), but here in the flat-lands of Southwest Florida, I find that 6 meters performs the best in both vehicle to vehicle and fixed station to vehicle propagation. My wife and I are both amateurs, and have 6m, 2m, and 70cm FM a...

This is a common problem with older BPR-40s, or those that have been exposed to a lot of heat. The BPR-40 has two ceramic filters, one for wide band and one for narrow band. There is a cushion (Part Number 75012112001) that is placed on top of the two filters (they are side by side). When this cushi...

Joined in 2007. Still in holding pen. Could someone let me out of my cage?

Thanks!

John

I have just received a large number of MT1000 99 channel VHF units to repurpose (Commercial to Ham). I have set up the first unit (this is my first experience with the MT1000, but have a fair amount with other Motorola radios). I see now that there is no "clone" feature in the RSS to copy ...

Not a bad idea. I am in no rush, but the board stares at me every time I go to do some other work on the bench. It would be a trivial job if I could get the parts!

"Other than from the Motorola parts department?" Yes, perhaps I am optimistic, but at their prices, I was hoping to find someone who might be willing to let it go for a bit less. Looking at the spec sheets for both, I know I can fit the commercial version with some pin bending and a few co...

Could you let me know where I could buy one? None of my suppliers seem to have any idea.
John
AA4TX

Thank you for the information. Does anyone have any ideas on procuring a replacement for this device, or a work around?

John
AA4TX

Just opened the VHF Spectra - it has a TDA7255 - also a 15 pin. Is it possible that the UHF has a TDA7255 mislabled as a TDA7256? This seems very strange. Anyone with experience with the audio section here?

John
AA4TX

Yes, I saw that before I posted. It seems as though there are / were two version of this chip. A 15 pin version and an 11 pin version. The spectra uses the 15 pin version. All I can find now is the 11 pin. I was hoping that there might be some old stock hanging around out there. It looks as though w...

Does anyone know of a source for the TDA7256, the audio amplifier in the Spectra? I was given a VHF and a UHF mid power set, but the audio amplifier in the UHF unit is dead. Shows signs of obvious heat damage, as does the speaker wire that was associated with it. Looks as though a pinch in the wire ...

I was just wondering if anyone else has seen this problem. I maintain several systems that use BPR40s. I have lately had quite a few come back with the problem that the noise squelch stays open on narrowband frequencies (green busy light all the time). The squelch is fine on channels that are progra...