Rick, is there any truth to the old RF Technician's tale that it takes more
than a Volt of RF to overload a PTO on a Corsair II? Does the 560 / 561
play nice on the low bands in Europe at night or do you need a 546 / A / B /
C... with the pre-selector?
73 & DX,
Gary - AB9M
-----Original Message-----
From: Rick - DJ0IP / NJ0IP
Sent: Thursday, October 02, 2014 1:48 PM
To: 'Discussion of Ten-Tec Equipment'
Subject: Re: [TenTec] Modern version of the Tec Tec Corsair - please Ten
Tec!
Wade,
I quit wearing the cape; no more phone booths here.
They went away years ago.
People who have never operated in Europe simply have no perception about how
much worse condx are here on the low bands.
It has gotten better since the broadcast stations on 40m moved up and out of
our band, and they widened the band from 100 to 200 kHz.
The problem most radios have here at night is with Intermodulation
Distortion.
We have a nice name for it in German. We call it "Wave Salad".
It is basically an S5 to S9+30 noise level across the entire band, depending
on which radio you have.
The problem is front-end overload.
The better the BDR3 is on the receiver, the lower this noise level will be.
Keep in mind that these are noises which are not really there.
They are basically phantom signals caused by the front-end of the receivers
overloading.
In general (with extremely rare exceptions), radios with upward conversion
have about 20dB worse BDR3 than radios with downward conversion.
To understand the magnitude of the problem, each dB improvement in BDR3 will
reduce the IMD by about 3dB.
So if I improve the RX front end by 20dB, it reduces the IMD by 60 dB, which
means it pretty much disappears, except for a few exceptions.
There are a couple of things you can do.
First and foremost, use an attenuator.
10dB of attenuation will reduce IMD by 30dB.
Of course if the station you wish to work is a weak DX in the Pacific and he
is only S1 or S2, switching in 10dB or more attenuation drops him into the
noise (the normal noise).
Better is a good preselector. These typically have 6dB insertion loss but
drop IMD by 30 or 40dB.
This is the route I went prior to the Orion.
The Orion was the first radio I ever operated in Europe that did not need a
pre-selector.
I never experienced intermod on it except when operating with a 3 element
yagi on 40m and pointing the antenna N-NE.
In that case I could hear a few phantoms at about S2 or so.
In the meantime there are several radios that are this good.
The K3, several of the Flex radios, the Eagle, the TS-990, and of course the
Hilberling are all good radios needing no pre-selector.
Nearly 15 years ago I made some recordings of a Jupiter with and without the
pre-selector and sent it to Ten-Tec.
After reviewing them, Jack commented that he had always heard condx were
worse here in Europe, but never knew they were of that magnitude. As a
result, he immediately added provision for a pre-selector to the Omni VII
design, which was still on the drawing board.
The Argonaut V was pretty much a disaster here.
The author of the QRP section of a local magazine described its receiver as
pretty much useless on 40m.
Sales here were pathetic.
Yet in the states it is a fine radio.
The Paragon with its upward conversion will have a blanket of noise (wave
salad) across the 40m band, when used with a good antenna.
The good news is, if you live in the states, you will never experience this.
73 - Rick, DJ0IP
(Nr. Frankfurt am Main)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Wade Staggs
Sent: Thursday, October 02, 2014 7:49 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Modern version of the Tec Tec Corsair - please Ten
Tec!
*Hello Rick,*
* Over the last several years, I have found real
respect for your Facts and Opinion. Could you please expand and explain. I
know that in Europe, you have a whole different bunch of problems from
Broadcast Stations but, can you explain just what feature... IF, Selectivity
or other, where the Paragon falls short? Would a Band Pass filter help? I
call 4 to 7 HF Nets a week on 80/75 Meters. With the RF Gain backed off ((
like we ran our Corsair )) and the 1.8 KHZ Filter selected, even with Loads
of QRM, we can still hear stations that others miss. Even to the point that
other NCS stations always ask me to relay weak signals into the Net. When
they know I am on frequency that is. Of course they are running mostly
KenYaeCom Rigs. My antenna is nothing special. 126 feet of Flat Top Dipole
with Windows ( 450 ohm ) Line into the tuner. A real Cloud Burner (( NVIS ))
at about 30 feet high. While I have your attention Rick, Thanks for
answering my many questions that we would have ask, if others had not ask
first. Do you wear a Solid Blue Shirt with a Big Yellow S on the front?? Do
you get your Cape caught in Car Doors? Well. I believe that you do. Do they
still have Phone Booths for the quick wardrobe changes in Germany? *
* Thanks Rick 73 from
Wade/KJ4WS*
On Thu, Oct 2, 2014 at 11:34 AM, Rick - DJ0IP / NJ0IP <Rick@dj0ip.de> wrote:
Come to Europe Wade, you'll learn the difference (in favor of the
Corsairs).
Upward conversion struggles here.
73 - Rick, DJ0IP
(Nr. Frankfurt am Main)
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of Wade
Staggs
Sent: Thursday, October 02, 2014 6:15 PM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Modern version of the Tec Tec Corsair - please
Ten Tec!
*Good Morning,*
* While the Corsair and Corsair II are fine
radio's. If you really want to split hairs, my Paragon ( 585 ) has
everything they have, plus very accurate ( no drift at all ) frequency
control. Don't believe me? Just find someone who owns one and sit
down in front of the rig. Now engage the 20 Db. pad and turn the RF
Gain back just a little bit. ( this is on the low bands ) It just
seems like a different world. And while I am posting. Why did the
Paragon and Paragon II have relatively short production runs? I know
about the Dreaded ... PLL Out of Lock ... problem with the 585 but
once fixed, they are such Great Radio's.
Mine was acquired while broken but a thorough re-work of the Major and
Minor Loop Boards has turned it into a real Keeper. Almost 6 years now
with no failures or issues of any kind. Although about 6 months back
we did replace all capacitors in the PA enclosure. So, in summary, has
anyone used a Paragon ( 585 ) lately ? ? ? And who wants to trade
their broken one for something else? All input about the Paragons
receiver appreciated.........
The Transmitter is Awesome also.*
*
73 from Wade/KJ4WS*
On Thu, Oct 2, 2014 at 6:42 AM, Rick - DJ0IP / NJ0IP <Rick@dj0ip.de>
wrote:
> As nice as its audio was, the KWM-2 would not be very good with
> today's crowded bands.
> The famous "Collins mechanical filter" was not really very good by
> today's standards.
> A 4-pole crystal filter on 455 kHz is as good or better and of
> course you can buy 6 or 8 pole filters now.
> And the DSP filters on lower frequencies are even better, sharper,
> and have steeper skirts.
>
> As long as we're dreaming, I wish I had 1960's band conditions again!
>
> All things considered, it's hard to beat the Corsair with its
> combination of good audio and good crystal filters.
> Newer radios have better filters but worse audio.
>
> For my money, the best compromise is the Eagle.
>
> 73 - Rick, DJ0IP
> (Nr. Frankfurt am Main)
>
>
> -----Original Message-----
> From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of
> Martin Sole
> (HS0ZED)
> Sent: Thursday, October 02, 2014 11:37 AM
> To: Discussion of Ten-Tec Equipment
> Subject: Re: [TenTec] Modern version of the Tec Tec Corsair - please
> Ten Tec!
>
> I've long liked the analogue radio sound. So far my all time fave,
> just for the audio, is a KWM2 with that big 6x4 speaker, something
> about that warm sound seems magical. Next up from my current radios
> would be my Omni V. Not sure how that might differ from the Corsair
> but whilst generally pleasant it's not in the KWM2 league. Then the
> Orion 565 and Elecraft K3, bit of a mixed bag these two as they are
> both very variable but I've not yet been able to recreate the
> analogue sound. I might need to experiment with amplifiers right at
> the point the signal becomes analogue. A god analogue audio amp with
> LTP input and complementary pair output in discrete silicon feeding
> a big speaker,
might sound very different.
>
> The TS940 had good audio too but for me about the same as the Omni V
>
> Martin, HS0ZED
>
>
> On 02/10/2014 12:03, Barry N1EU wrote:
> > On Wed, Oct 1, 2014 at 5:12 PM, John Farler
> > <k4avx1@windstream.net>
> wrote:
> >
> >> I have a Corsair II with the DDS VFO, which works nicely. I
> >> think it's a single conversion though.
> >
> > Normally it converts to 9MHz, then to 6.3MHz, and then back to
> > 9MHz, unless you bypass the 6.3MHz PBT i.f. which can be done
> > fairly easily but you lose PBT and narrow filters and don't gain much.
> >
> > I agree on the CAT comment. I always dreamed of adding a CAT port
> > to the DDS cpu firmware.
> >
> > 73, Barry N1EU
> > _______________________________________________
> > TenTec mailing list
> > TenTec@contesting.com
> > http://lists.contesting.com/mailman/listinfo/tentec
> >
>
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