[NLRS] Deafness on 6M

[Jon Platt]

Here is my 2 cents worth:


> Puzzles:
> 1) why do I get channel 2 at 50.75, when it should be at 59.xxx MHz?
> partial answer - because I can also hear it on the HF rig at 9 MHz FM -
> solid, but not showing much of an S-level.
> Now, why on earth do I have it at 9MHz?

RF everywhere.   You are so close to strong RF that even your bed springs
are a mixer.  Things that you don't expect to be mixers are mixers.


> 2) Is the reason I'm deaf because of local stations overloading me?

That would be my guess.   The front end of a Ten-Tec transverter is not well
know for its selectivity.


> 3) The Ten-Tec has only a 7 db or so NF - while other transverters have a
1
> db NF.  Is this a big deal on 6M?

You don't have a NF issue, but more of a dynamic range issue.   And yes, a 7
dB NF may be somewhat subpar for 6m .... I would think that something closer
to 3 dB or a little less would be more optimum for that band.   On the other
hand, adding such gain will only make you problem worse (back to dynamic
range again).

> Solutions?

I would consider adding the ICE helical filter cavity.   I believe that they
are around $100 or so .... I use one on 2m that gets rid of a lot of crud.
With the helical filter in-line, at least you know that you are dealing with
only in band issues.   With all the crud that is going on, who knows where
your problem signal(s) are originating as they could be (at least partially)
originating in your wide band receiver.

After this, you may want to consider upgrading your 6m station to a high
dynamic range system.   An example of this would be the DEM 6m transverter
in combination with a good HF transceiver.   Maybe someone has such a 6m
station that they can loan to you to see if it helps get rid of the crude
before you invest ... as I am 25 miles away from Ch 2 and using a low
antenna I'm just running a little FT100D with no problem .... my problem is
radar "clicks" on 1296, especially when looking SSE.

Last, consider the use of high Q notch filters to get rid of specific mixer
products that are causing a problem.

A vertically polarized antenna can provide 10's of dB of help, but it will
be tougher to work long haul locals who are all horizontally polarized.

73, Jon
W0ZQ



> Do I need a cavity on 6M?
> Tuned stub for 59MHz?
>
> 73's - bryan kb0obt
>
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