Lee,
I think it is impossible for anyone to predict what is going to happen when
using an indoor antenna.
I don't expect the Jupiter to work better than the Kenwood in combating
those specific problems, but the Jupiter is a fine radio.
You have three problems you're fighting:
1) Very weak "wanted signal" compared to when using an outdoor antenna
2) The garbage being picked up by the antenna inside the house from consumer
products
3) Common Mode Current (CMC) from the antenna radiating into its own coax
line, which is what is making the transceiver go crazy.
There is no silver bullet for #1. By far and away the best thing I have
ever used indoors is a magnetic loop antenna. I have even used one out of
the basement of a hotel and still worked all over Europe with it (BTW - I'm
in Europe, so that was not DX). If you can, run a nearly invisible wire out
into the yard to a tree. You can use thin copper enamel wire. Then remove
it during the day. This will outperform anything you do indoors.
The magnetic loop will also help a little with #2. For one thing you can
rotate it, and sometimes that can help to reduce the level of disturbance
from the consumer products, thus dropping your noise level a few S-Units.
For #3 you definitely should buy or even better, build a good quality RF
Choke and insert it in the coax line directly at the transceiver. Most
people couldn't be bothered with taking the time to learn about good RF
Chokes, and thus think any old thing they buy is going to be good. Indeed,
any old thing will help but in tough cases, you need a good choke, not just
any old choke.
TWO KINDS of RF CHOKES: There is the Maxwell (W2DU) and the Guanella. MOST
commercial chokes are Maxwell and most people use this kind. This is the
"ferrite beads over coax" type of choke. It often will suffice but in tough
cases, the Guanella is a lot better - with a caveat. The W2DU is more
broad-banded; the Guanella is more frequency dependent but much better over
a limited frequency range. As a result, the Guanella will work much better
than the W2DU for several bands, but its suppression ability drops off above
and below these bands - however it still works as well as the W2DU outside
of those bands. SOUNDS COMPLICATED - BUT'S ITS NOT. (I can help you if you
like.)
For buying or building a W2DU, I would go to THE WIREMAN, model 8231 ($30)
or the kit version of it, 8331 ($20).
The model T4 or T4G from The Radio Works is just as good, but costs twice as
much and is big and bulky.
I haven't tried the low power version of the Radio Works choke so I won't
comment on it.
There aren't many commercial Guanella chokes available and the ones that
are, cost a lot of money.
These are "simple Simon" to build. Simply wind a piece of coax around a
toroid core and solder a PL-259 on each end.
The questions of course are always "which core" and "how many turns of
coax".
Here too a simple solution exists: Steve, G3TXQ has an excellent web page
with a lovely color (colour) chart showing which toroids and how many turns
of coax, frequency dependent.
See: http://www.karinya.net/g3txq/chokes/
IMO, STEVE'S PAGE IS ONE OF THE MOST VALUABLE PAGES ON THE INTERNET FOR US
HAMS! TNX STEVE!
Here is a picture showing how easy it is to home-brew:
http://www.dj0ip.de/cmc-test/the-components/the-chokes/
Look at the 3rd choke from the top, entitled "C3".
>From the larger picture in the clickable gallery, you will see that I
cross-wound this choke.
However that is not necessary. You can simply wind the coax in one
direction, all the way around the toroid. The only advantage of
cross-winding is that the two ends of the coax exit the toroid on opposite
sides.
I think this one cost me about $10 and it is SUPERIOR to the W2DU type
chokes.
If you want to buy a Guanella choke:
http://www.balundesigns.com/servlet/the-32/balun-designs-baluns-1-cln-1/Deta
il
($65)
UNFORTUNATELY I cannot guarantee that any of these will make a significant
difference to the RX noise - there's a good chance they will help, but no
guarantees.
But they should fix the problem with the transmitter going crazy above 40w.
Good luck, Lee!
73 - Rick, DJ0IP
(Nr. Frankfurt am Main)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Lee
Sent: Thursday, April 24, 2014 1:28 AM
To: tentec@contesting.com
Subject: [TenTec] New Jupiter on its Way _ A Few Questions
Just bought a lightly used blue screen Jupiter. I operate with an indoor
dipole at up to 40 watts. With my Kenwood, anything higher than 40W made the
transceiver go crazy. I have been using a 'floating' ground, because I'm on
a 2nd story condo and a good rf ground is well nigh impossible. Will the
situation be much worse with the Jupiter, you think?
Also, do you think the TT 707 Mic is a good match with this rig? Any other
less costly mics you would recommend?
This will be my first TT rig in my short ham career. I live in an ultra high
qrn environment, and the Kenwood was just grating to listen to. All the NB,
NR, and dsp was useless against the constant S9 onslaught. Do you think the
Jupiter would be any different?
Lee (NY6P)
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