[Hallicrafters] Dummy antenna for S40 alignment

[George]

Hi Bill,
That's a good assessment, but if you dont have the proper balance between 
the tx and rx alignment, your up the creek. I only have one antenna and 
tuner. For your way to perform its magic you would need two antennas, or be 
strictly an SWL. It would be most noticeable tuning up a transceiver, but 
no different with separate sets. The exception would be the 
combination  has an rx antenna trimmer to compensate. Without the correct z 
at the antenna/radiator on both, you would have to re-tune the tuner at 
each tx/rx changeover. The reciprocity would get lost in the mismatch 
between the two. I only mention this having learned it the hard way. Theres 
no free lunch.
Good luck, George KB2Z


At 09:26 PM 12/10/04 -0500, you wrote:

>Exactly right, and that is why in all my station setups, I have used 450 ohm
>balanced line and a tuner.  This is the only way I know, that my receiver is
>seeing the impedance it wants to see and I am getting maximum signal
>transfer.  How do I know this?  Because the transmitter is tuned to the same
>frequency which is typically at or equal to 1:1 via the tuner.  Therefore, I
>also have a low SWR for the receiver as well.
>
>I tried this little experiment, I pulled my SX-111 off line and connected
>the rear antenna connector to my MFJ-259B with a short piece of coax.  I
>then fed the MFJ signal into the receiver right in the middle of the 40
>meter band.  Using the front panel trimmer on the SX-111, I was able to get
>a nice 1:1 SWR between the MFJ unit and the receiver.  Turning the main
>tuning knob on the receiver from band edge to band edge, saw the SWR slowly
>creep up to way over 10:1 at the band edges with attendant signal loss.
>
>Hence, a good SWR is as important for your receiver as it is for your
>transmitter.
>
>K2WH
>
>-----Original Message-----
>From: hallicrafters-bounces at mailman.qth.net
>[mailto:hallicrafters-bounces at mailman.qth.net] On Behalf Of Al Parker
>Sent: Friday, December 10, 2004 8:52 PM
>To: Craig Roberts; Edward B Richards; hallicrafters
>Subject: Re: [Hallicrafters] Dummy antenna for S40 alignment
>
>hi guys,
>     The main thing you wanta do is set up the rcvr for what impedance you
>plan to feed into it.  If the S-40 has no antenna trimmer, then you can't
>do any adjusting other than your alignment, e.g. SP-600.  If it does
>you've got some leeway. (don't stop hr)
>     A resonant antenna is resonant on only a very narrow band of freqs.,
>whether it has a balanced, open wire feedline, or what. So, elsewhere, the
>impedance is gonna be off, sometimes way off.
>     What you really wanta do is use an antenna tuner for your receiver if
>you're "band cruising" no matter what antenna you use.  You've either
>gotta tune the antenna system to the rcvr or the rcvr to the ant. sys.
>     I've done it, and demonstrated it to others, with SP-600's.  Any wire
>is gonna be a very high, or very low impedance in many places across the
>SW bands.  You can hear something then, but if you use a tuner and adjust
>it to feed the rcvr in the imp. range it expects, just like "we know" we
>hafta do with a transmitter, you'll hr more.  tuner - that's how you get
>the best transfer of energy, rcvg or xmtg.
>     that's my story & I'm stickin to it.
>73,
>Al the grouch
>W8UT
>
>----- Original Message -----
>From: "Craig Roberts" <crgrbrts at verizon.net>
>To: "Edward B Richards" <zuu6k at juno.com>; "hallicrafters"
><hallicrafters at mailman.qth.net>
>Sent: Friday, December 10, 2004 5:19 PM
>Subject: Re: [Hallicrafters] Dummy antenna for S40 alignment
>
> >
> > I was actually toying with the idea of building an old style open feeder
> > line doublet, per Army instructions, for my Hammarlund SP-600 (which has
> > a 100 ohm input impedance) and seeing if it would make any discernable
> > difference.  Does anyone feed their antique receiver with an antique
> > resonant antenna?  If so, how's it work?
> >
> > 73,
> >
> > Craig
> > W3CRR
>
>
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