Still raining here with wind and I don't feel like crawling up and down
a ladder to put it in the attic, nothing is waterproof right now so I'm
fiddling with it in the basement. I get good groundwave but because of
the chicken wire in the walls, plumbing, wiring and etc. nulls are useless.
Spending a few $ on wireless cards for the computers and using the
bedroom media computer as firewall/router with the cable modem stuck
inside the case got rid of most of my domestic birdies. 2 Gigabit hubs
will be on Ebay soon...
I teat the "textbook" like a recipe book, gives a starting point but
often needs some adjusting. Just for grins I did hook the preamp to the
4 turn coil. The resonant freq, with 1V at the varactor junction, about
520pF, Is about 530KHz instead of just above 540. Signal strength with
biasing the same was about 6Db down going by the S-Meter on a strong
station with attenuation set the same. Might just use it that way since
the lower input EMF is less likely to cause intermod problems and the
preamp has plenty of gain to spare.
Less interaction probably because of the Bazillion Ohm input impedance
vs. the 50 Ohm feedline impedance usually used. At 9V it still tops out
at about 1650KHz.
Still waiting on back ordered parts to finish the mods to my receiver,
hopefully I'll have them before next winter...
On 4/10/2011 14:48, Russ Edmunds wrote:
If the "textbook" number of turns on a given size frame is x, and you use a two turn link/pickup
coil ( which is the usual number ) you will now have "x + 2", and may need to reduce the number of
turns needed in order to reduce the "L". That will be pretty obvious as the loop won't tune the
whole band. If x = 10, then using a link/pickup coil, you will likely need 8.
One of mine is amplified with a dual-balanced FET amp ( 2N4416's IIRC ), and it
is directly coupled. When I used it unamplified, I added a two-turn link coil,
and had to reduce the main/tank coil accordingly. I never tried using a link
coil with an amplifier.
Russ Edmunds
15 mi NNW of Philadelphia
Grid FN20id
<[email protected]>
FM: Yamaha T-80& Onkyo T-450RDS w/ APS9B @15'; Grundig G8
AM: Modified Sony ICF 2010's barefoot
--- On Sun, 4/10/11, Tim Hills<[email protected]> wrote:
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