Search found 11 matches

by AmRadiant
Fri May 12, 2006 8:48 am
Forum: AM transmitters
Topic: Portable MW antenna?
Replies: 7
Views: 31100

MFJ 945E 1.6-60MHz 300W antenna tuner can work in the upper region of MW (1593 and up)?

Do you import Autek antenna analyzer?

Thanks!
by AmRadiant
Fri May 12, 2006 8:41 am
Forum: AM transmitters
Topic: Portable MW antenna?
Replies: 7
Views: 31100

many thanks for suggests, I've see some interesting objects, too :)
by AmRadiant
Thu May 11, 2006 8:32 am
Forum: AM transmitters
Topic: Portable MW antenna?
Replies: 7
Views: 31100

maybe I've defeated the law... but my tx 0.8W whit a dummy load in very open space make about 100-120 meters.

Coaxial cable was only 2 meters.
by AmRadiant
Tue May 09, 2006 11:06 am
Forum: AM transmitters
Topic: Portable MW antenna?
Replies: 7
Views: 31100

Portable MW antenna?

Hello all, it can be a silly question, but I'll try... What do you think about "portable" antenna for MW? Of course with a tiny fraction of power irradiated (with a tx about 500 mW- 1W out) and 200-300 meters (at best) of rx radius... With a car, is better a (very) short vertical antenna (...
by AmRadiant
Thu Mar 09, 2006 10:06 am
Forum: Schematics - help and ideas
Topic: AM broadcast amplifier
Replies: 7
Views: 34892

This is what I'm talking about. Now you're in trouble and want to move more into non-linear region to prevent overheating? Yes, you can do that, but modulation quality suffers. This is why my approach is better. Eh eh, ok... you are true of course. I think that for now this is the way (I think that...
by AmRadiant
Tue Mar 07, 2006 12:10 pm
Forum: Schematics - help and ideas
Topic: AM broadcast amplifier
Replies: 7
Views: 34892

With AM you need 4x the carrier power in modulation peaks, which means you will get 30W/4, which is 7W carrier at best. Lots of trouble for a result that will likely dissapoint you. Oh yes, now I've understand what do you mean :o (transistor total failure!) what do you think about AB class? It's mo...
by AmRadiant
Mon Feb 13, 2006 6:03 pm
Forum: Schematics - help and ideas
Topic: AM broadcast amplifier
Replies: 7
Views: 34892

I've make some test with a 2SC2078 with a very ugly and simple mine schema (680 ohm 1W resistor plus 1 KOhm trimmer in series from base to collector, an "rf" choke positive Vcc-collector, 10nF capacitor from cold side of choke and earth, in/out capacitors and a BIG fan)... with 70 mW in I'...
by AmRadiant
Thu Feb 09, 2006 5:34 pm
Forum: Schematics - help and ideas
Topic: AM broadcast amplifier
Replies: 7
Views: 34892

(CUT) Its just a bad way to go about it. Its much better to modulate the output stage directly. Yes, you are true. But sometimes linear amplifier can be useful, for example with small PART 15 transmitters (100 mW max output) that works good and stable (pll or quartz controlled). I think that a pair...
by AmRadiant
Thu Feb 09, 2006 10:56 am
Forum: Schematics - help and ideas
Topic: AM broadcast amplifier
Replies: 7
Views: 34892

AM broadcast amplifier

Can you point me in the right direction? I need a (simple) schema for a not so big power linear amplifier for AM Broadcast... for example... 100mW in 2-5-10 W out. A class A would be very nice also, maybe with cb final transistor (2SC1969, 2SC2078, or BD135, BD329, ecc..). I've tried only one work f...
by AmRadiant
Thu Feb 09, 2006 10:16 am
Forum: Schematics - help and ideas
Topic: fm amplifiers
Replies: 2
Views: 19775

Re: fm amplifiers

Hi I am trying to locate plans for a low power !/2 to 1 watt fm. Also I have a dumb question. Would a 5 watt am amplifier work on fm? Thanks For any possible help Ken 5 watt am amplifier? where is? :o Do you mean AM Broadcast (530-1620 khz) or CB? I search AM broadcast amplifier projects from long ...
by AmRadiant
Thu Feb 02, 2006 10:42 am
Forum: AM transmitters
Topic: Home Brew ISOTRON
Replies: 13
Views: 131600

Re: New ISOTRON

I have now completed a new Isotron for the lower part of the MW band on a 160mm PVC waste-pipe. SNIP VERY INTERESTING! Can you point me in the right direction about frequency vs. lenght reduction loss (from capacitive hat to capacitive hat) vs. efficiency? My frequency is 1602 khz but I haven't muc...