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Old January 19th 04, 08:30 AM
Pete KE9OA
 
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It should be good..............I am shooting for a +40dBm IP3 on the loop
amplifier. About that 6790, the IP3 on that unit is rated at +30dBm, which
isn't bad, but they do have a wide open front end. Still, I haven't had any
overload problems with mine. It is my favorite receiver, but it so is
BIGGGGGGGGGGGGGGG. Maybe, when I buy a house, I will build a nice deep night
table to keep it on. When you open up the 6790, you see that the
construction is very good. All of the RF modules are enclosed in a die-cast
"egg crate construction" style of assembly. The 45MHz I.F. filter is at
least 8 poles, so the 2nd mixer is protected quite well from out of bandpass
stations. I got mine from Ken G. down in St Louis. He is a great person to
deal with.

Pete

"Eric F. Richards" wrote in message
...
"phil " wrote:

hi Eric:

Oh, I don't argue *that*, I just argue that it wasn't resonant.


if you knew that then why use this antenna for LW?


Sigh... round and round we go... because it was very effective for my
needs, specifically picking up NDBs east of the site. Which it did
very well.

Not that it matters, really, my WR-G303i reports its signal strength
as 30 mV 120 miles away on a 400 foot wire broadside to the antenna.
Flamethrower, indeed.


30mV at what frequency? can you fault the R8B and R75 for overloading?


...what are you, totally thick or what? The MW station that was
causing the problems.

Dunno. I don't keep up with the local doings of the broadcasters
much. I assume they are in the old standard TV UHF band; 47 CFR 369
says that from 470 to 890 MHz, field strength on Table Mountain must
be less than 30 mV/m.


that PAR LPF should severely attenuate UHF. spectral analysis of that

wire
is needed. low frequencies or potent RF energy can cause PIN diodes to
rectify.


The PAR LPF has no relevence to the federal regulations regarding
Table Mountain. What's your point? HDTV broadcasters at Lookout
Mountain are griping about the regs. My point, in case you missed it,
again, is that the flamethrower is in violation of the regs in 47 CFR
369.

No radio is perfect; the '7030 wouldn't hold up out there... To me
the question would be whether or not the '340 would.


the 7030 uses an SD5400 first mixer and has 40 dB of attenuation on

tap...
add a $50 homebrew LW BPF: your RX340 will overload first. either way an
R75 hooked to a LW loop will hear more NDBs.


Of course. The R75 solves all. Can't imagine that if you use your LW
loop with another radio, that it'll outperform that R75, can you?
Come on, this is really simple. Take whatever crutches you add to
your R75, apply them to nearly ANY other radio on the market, and
it'll leave your R75 in the dust. (Notably, your dream radio, the
Racal 6790, would be left in the dust as well. What's your affinity
to radios with crappy front-ends?)

Eric, you remind me of Captain Ahab, fighting that whale of an antenna,
Moby Dick. man versus nature, a classic... but the SOB already bit off

your
leg. shake the obsession... build a LW loop.


Actually I'll probably purchase what Pete comes up with, since his
loop probably will have a low NF and resistance to overload. Just a
guess. We'll see.

regards,
phil


So, what's the deal with the R75 schematic on Yahoo? I've been trying
to retrieve it for a week and the server acts dead. Is Yahoo that lax
in running their servers?

--
Eric F. Richards,
"The most likely way for the world to be destroyed, most
experts agree, is by accident. That's where we come in;
we're computer professionals. We cause accidents."
- Nathaniel S. Borenstein