[Kenwood] TS-480 extended transmit?

Thu Dec 3 17:08:35 EST 2009

On 3 Dec 2009 at 10:06, Alex Eban wrote:
> The old marine band is at 500kHz, I know, I've been there.

Yes. So have I.
> The power amplifiers of Kenwood are not designed to operate under
> approximately 2 MHz by choice of core materials of the transformers.

Fine. But I was not talking about any power output. 5 watts, or less, would 
be ample. We have amplifiers. :-)
> Their inductance is too low to operate efficiently at lower
> frequencies.

Again, we don't care about "efficiency" down there. We feel that since the 
receivers work just fine down there, the transmitters should be able to 
output something useable down there too.
> Coupling and filter capacitors are also calculated for
> 2MHz operation also.

Yes, thank you, we are aware of that. Nonetheless...
> If I remember good, there are also band limiting
> filters in the `480.

Well, if the 480 is anything like the 940, those aren't really all that difficult 
to deal with.
> as far as I know, no Kenwood wad made to work
> under the BC band frequencies (530-1610 kHz)-receive only, no transmit
> there.

Both the 850 and the 940 have been proven to work just fine down there, 
although one must remove or modify a certain coupling inductance from 
the receiver input section to get the sensitivity back up to where it is on 
the higher bands.
In fact, the 480 has a jumper inside it for this specific purpose.
It appears that Kenwood purposely makes the receiver sensitivity at the 
BC band and lower at least 20 db below that above the BC band because 
they were concerned about receiver overload from strong local BC 
stations.
Thanks very much for the information and advice. Much appreciated.
vy 73,
Ken Gordon W7EKB