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Texas Star Linears on the amateur bands?
- Thread starter TonyV225
- Start date
Another favorite of mine..."Throw that ALC cable away...no doggone ALC ever did nuthing for me and my radio. Nothing has caught fire here, you don't need it."
Lot of wives tales and misinformation out there and almost as many dirty signals.
The amps everyone is talking about are for 10-11-12 mtrs.If you use them on am on 11 mtrs you might be splattering on 10 mtrs.That is if you have the modulation high.Swing kit,super mod kit.I will keep my 572b amp.73s de JW
well just because i had nothing better to do, i had my TS-500 re-worked by someone who use to be on this forum. They put in regulated biasing and a little bit of additional fitering. With that said as you went down in the bands so did the ouput power. Without the switchable filtering the amps efficiency went down accordingly, it was relatively clean when driven with no more than 10 watts on an o- scope. That said total investment was $183 dollars... but it was still a Texa Star amplifier.
B
BOOTY MONSTER
Guest
ive got a 500 v . 16-17 watts gives me about 500 watts modulated and the variable on the radio is set to make the 500v deadkey 125 watts . i get great comments on how clean my TX sounds and i havnt had any bleed over compliants so by CB standards im pretty clean i think .
but by ham standards im probally a pig in its mud hole, hehehe . but i understand yall have much higher requirements for the equipment yall run . kinda like Ford vs. Bently . lol . i also understand all equipment is at the mercy of its operator to run it properly , or not .
but by ham standards im probally a pig in its mud hole, hehehe . but i understand yall have much higher requirements for the equipment yall run . kinda like Ford vs. Bently . lol . i also understand all equipment is at the mercy of its operator to run it properly , or not .
another option would be to use a tunable "within the band" single band antenna like a loop. it can't send out harmonics if the antenna isn't resonate "able to spew them out". the antenna then becomes a filter itself. an antenna tuner is a filter too. so build an antenna for each band you want to talk on and have at it. stop using trap multi-band antennas.
I wish it was that simple but it is not and you are completely wrong on that account. If that was really the case then an antenna would "filter out" the harmonics from a dirty amp and it simply will not do that. The harmonics will still be radiated but at a slightly lower efficiency than the fundamental frequency. It it was true that would never be a case of TVI caused by harmonics since a CB antenna is tuned to 27 MHz and not 54 or 81 MHz.
On edit: I forgot to add that although a tuned loop antenna is generally a high Q antenna meaning it has a very narrow bandwidth it can still radiate harmonics. In the case of an antenna tuner acting as a filter, I will agree with that however it does not hold true in all cases. An antenna tuner can attenuate harmonics considerably but there are also times when it makes pretty much no difference depending on the complex load at the other end of it and the settings of the capacitors as well as the type of tuner configuration with the SPC (series parallel capacitor) being the best at rejecting harmonics. The tuner should also have a very good earth ground for best rejection of harmonics.,
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you just confirmed what i stated. you said "slightly lower efficiency" well that slightly lower is more than your making out to be. as the radiator isn't going to want to radiate it fully. and it has been agreed earlier in this tread, that if the amp is ran within it operated tolerance. 12 to 13.8 volts and not over driven. then a texas star amp with 2sc2879's will produce side products somewhere in the -30db and lower within a tolerable range "says the datasheets" for that particular device. so it's already within tolerance. now back that up with a tuned magnetic loop. it's narrow band will effectively reduce that farther. it acts as a filter, not effectively radiating the harmonics fully. and yes a filter needn't erase the side product fully. just to a tolerable level. that's just what the tuned magnetic loop does. and that filter; it lets some of the harmonics go out in the air too. at a slight lower efficiency. but within tolerance.
The datasheet if for a single ended amp with optimal load impedance for the drive level and vcc,
imd -24db @ 100w, about the poorest 12v device out there at its rated output,
imd caused by none linear response of the device generates sidebands & adjacent channel interference,
These guys are talking about harmonics which can be attenuated with a simple bandpass filter not imd which can't,
The pushpull topology of the texas star should cancel even order harmonics but not odd order harmonics.
imd -24db @ 100w, about the poorest 12v device out there at its rated output,
imd caused by none linear response of the device generates sidebands & adjacent channel interference,
These guys are talking about harmonics which can be attenuated with a simple bandpass filter not imd which can't,
The pushpull topology of the texas star should cancel even order harmonics but not odd order harmonics.
I;m confused, .......just what then, is a partially radiated harmonic?
just to be clear,........... are you saying that a non resonant (or even a resonant) antenna does not radiate ALL the RF power inputted to it?
no, I'm not talking about any loss in the coax due to "heat" generation, I'm strictly referring to the antenna AFTER the feedpoint.
I've tried to use a Texas Star 500 & 667 on 40m & 80m but no chance. Filters & combiners are all wrong.
I've a friend who rebuilds them to work well on the lower HF bands but without heavy bandpass filtering. He relies on a tuned mobile antenna to act as an harmonic filter.
I've a friend who rebuilds them to work well on the lower HF bands but without heavy bandpass filtering. He relies on a tuned mobile antenna to act as an harmonic filter.
Nope. Not in the slightest.
At least someone gets it.
Relying on a tuned mobile antenna for harmonic suppression does not mean it works as it should.
I ran a commercial FM broadcast transmitter into a sharply tuned single channel four bay antenna. The transmitter met spec for harmonic suppression however it still required an optional external TVI filter to reduce harmonics due to the presence of TV channel 10 in the same area. WHY? The highly tuned sharp response of the antenna did not filter out harmonics to any degree that's why. This antenna was so sharply tuned that a little ice on it would drive the SWR up quite high. The transmitter was a tube type BTW. A tuned antenna is simply NOT an effective harmonic filter that can or should be relied on. There is NO substitute for a lumped constant harmonic trap.
Probably why I had to add a Dentron manual antenna 'tuner' (T-coupler) after the amplifier so my engine would cease to cease when transmitting
Probably why I had to add a Dentron manual antenna 'tuner' (T-coupler) after the amplifier so my engine would cease to cease when transmitting
Indeed probably why. In some cases an antenna tuner will offer very little in the way of harmonic suppression however there are certain tuning situations where harmonics can be greatly reduced, not as much as with a low pass filter , but 10,20 or even 30 dB or more is common. By contrast my Barker & Williamson LPF has a minimum of 72 dB suppression.