Diversity receive w/o dedicated receive antenna

[K7TV]

I totally agree with Jim. Diversity receive is the only way I use the second
rx, and I never invested one cent in extra antennas for the second receiver.
For use with my horizontally polarized main antenna I just connect the
second rx to my existing vertical, which works fine even on bands that it is
not designed for. At Field Day I put up a BuddiPole vertical with no coil
and no attempt whatsoever to tune to any band, with a single wire
counterpoise of random length. If I didn't have the vertical at home, or the
BuddiPole for the field, I would just use two pieces of wire and suspend
whichever way is convenient. However, assuming the antennas are not far from
each other, it is important that they have opposite polarizations.

 

To have the second receiver and not use it for diversity is a tragedy. After
you set the rf gain on the subreceiver to get a decent balance between the
two receivers, you will find that the second receiver often allows you to
hear a station in the second rx that is temporarily unreadable in the main
receiver due to qsb. Also, in crowded band conditions the different stations
within the receiver passband will arrive with varying polarizations, and you
can hear them spatially separated like orchestra instruments on a stereo
"sound stage". This is helpful both for ssb and cw. Sometimes it can even
help with multiple cw signals on the exact same frequency.

 

73,

Erik K7TV

 

>Your second antenna  does NOT need to be resonant to receive, either by
itself or with another in diversity mode. My receive antenna is seasonal so
I have employed antennas for other bands for receive when it is not up.
While a non resonant will not present as strong a signal, it also will not
present as strong a noise. The S/N ratio is unchanged but the human ear
seems to hear better when the noise is reduced. I typically use an antenna
for the next band (even harmonic).

 

73,

Jim W5QM

 

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[Sverre Holm (LA3ZA)]

This is an interesting idea. But how is this, I have set up my K3 with the main and sub for use as independent receivers in e.g. a DX pile-up. Don't I then need to open the K3 and reconfigure/rewire it for use as a diversity receiver?

[Jon Kåre Hellan]

On 07/03/2012 06:08 PM, Erik Basilier wrote:

> To have the second receiver and not use it for diversity is a tragedy.

Probably true. But I very rarely have enough isolation between my
antennas. So if I try diversity, the front end protection relays start
buzzing when I transmit. The consensus seems to be that you shouldn't
rely on the relays.

The main antenna is simply disconnected while transmitting. Why isn't
the sub-rx antenna? You're absolutely right, as long as I can't use
diversity, dual watch would help me just as much as having a sub-rx does.

Jon LA4RT

After

> you set the rf gain on the subreceiver to get a decent balance between the
> two receivers, you will find that the second receiver often allows you to
> hear a station in the second rx that is temporarily unreadable in the main
> receiver due to qsb. Also, in crowded band conditions the different stations
> within the receiver passband will arrive with varying polarizations, and you
> can hear them spatially separated like orchestra instruments on a stereo
> "sound stage". This is helpful both for ssb and cw. Sometimes it can even
> help with multiple cw signals on the exact same frequency.
>
>
>
> 73,
>
> Erik K7TV
>
>
>
>> Your second antenna  does NOT need to be resonant to receive, either by
> itself or with another in diversity mode. My receive antenna is seasonal so
> I have employed antennas for other bands for receive when it is not up.
> While a non resonant will not present as strong a signal, it also will not
> present as strong a noise. The S/N ratio is unchanged but the human ear
> seems to hear better when the noise is reduced. I typically use an antenna
> for the next band (even harmonic).
>
>
>
> 73,
>
> Jim W5QM
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>
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> Please help support this email list: http://www.qsl.net/donate.html
>

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[Don Wilhelm-4]

Sverre,

No internal reconfiguration should be necessary to turn on Diversity
receive.  Ideally your sub and main roofing filters should be matched
for diversity receive.  I would think the filter selection should be
more permanent and would not be subject to reconfiguration.

73,
Don W3FPR

On 7/4/2012 4:01 AM, Sverre Holm (LA3ZA) wrote:
> This is an interesting idea. But how is this, I have set up my K3 with the
> main and sub for use as independent receivers in e.g. a DX pile-up. Don't I
> then need to open the K3 and reconfigure/rewire it for use as a diversity
> receiver?
>
>

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[Richard Ferch]

In a word, no. The internal rewiring only controls where the subRX gets
its auxiliary antenna input from (BNC RX-only port or ANT2 on the KAT3).
Either one will work in diversity receive, provided you connect your
second antenna to the correct connector. For DX pileups, you would
normally use the subRX's primary antenna input, i.e. the same antenna as
your main RX. You switch between the primary input (for DXing) and the
secondary input (for diversity) by HOLDing the RX ANT button.

73,
Rich VE3KI


LA3ZA wrote:

> This is an interesting idea. But how is this, I have set up my K3 with the
> main and sub for use as independent receivers in e.g. a DX pile-up. Don't I
> then need to open the K3 and reconfigure/rewire it for use as a diversity
> receiver?

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