Search results

If you have the resistive equipment, give it a try I suppose. But everywhere on the internet, everybody is using propane torch or butane to do these big soldering jobs.

Several tons of ferrite beads?? is this an RFI problem? Probably the best thing to do is borrow an oscilloscope, and use it to measure directly on the battery as your big audio amp is running. Observe any audio riding on the DC. Then after that, do the same measurement on the DC connector...

You wouldnt see any benefit from CW unless you narrow your receive bandwidth using filters intended for this narrow mode. Same goes for PSK31. Wont see benefit from the channel filter standard on 11m SSB rigs. But there are other modes available that you can reap the benefit, while using a...

In USA.. Regulations can exist at the federal level, if it involves interstate commerce. Otherwise, it must be regulated at the state level. However, with a practical consideration it makes sense to regulate radio at national level since signals cross state boundaries. But even though, its...

Integrity. thats it! All hams should "realize in their mind" the rule 97.113(a)(5) (a) No amateur station shall transmit: (5) Communications, on a regular basis, which could reasonably be furnished alternatively through other radio services. Dont ignore the rule or brush it off, its...

If this amp has good input return-loss and proper gain vs. current draw to operate properly at lower frequencies, I think not many hams would use this amp on ham bands. The reason is that biasing on these amps are unregulated, meaning that on modulation peaks, the bias current reduces...

You are a mobile unit, or base? You must be near an FM broadcast station. If so, find out some information about it. If you are a base-station at home, then thats a real problem for you. But if you are mobile, i could guess its only a problem if you drive near the transmitter station.

This describes the various methods for dealing with gain drift aka thermal runaway. www.qsl.net/va3iul/Bias/Bias_Circuits_for_RF_Devices.pdf

If you do need to replace a burnt 1969, there is a drop in. for example from ST microelectronics: 2ST1480FP seems to be slightly better than 2sc1969 and is a drop in. But if you want more power, you would be more happy with a small external power amplifier.

Ground absorbing RF power is a concept worthy of thought. Probably the best example of RF power on ground is with an antenna that doesnt have a counterpoise, or is inadequate. In that case there would be RF power on the coax shield, and the shield is radiating. So if there were harmonic power...

Any part of antenna system: antenna, transmission line, or filters and whatnot.. if they are not 50 ohms then they will reflect power back to the source (the transmitter). I dont know how there could ever be an exception to this rule. If a low-pass filter is absorbing harmonic power instead...

Filters are just capacitors and inductors. They will only absorb due to loss in the components. This loss is very low. Such as at the operating frequency of filter the loss is as low as half dB. But when operating at a higher harmonic frequency, the filter will reflect most of that power...

considering how many off the shelf FRS/GMRS combo radios are for sale that do five watts. I doubt anybody would notice a higher gain antenna on a half watts FRS radio. Or even the five watt models either. The FCC enforcement logs for GMRS are almost zilch. And FRS enforcement is nonexistant.

two meters if fine if you have an open repeater which covers both stations who wish to communicate to each other. The same would apply to UHF. However, if there are not any suitable repeaters, then simplex would be the option. The problem with simplex on VHF between ground stations, where one...

For normal operation, you would want your low-pass filter directly connected to your transmitter. You want to see your power to antenna without any harmonics. However, for testing your setup its useful to try your watt-meter between transmitter and LPF to test how much power the filter is...

The problem of class-C amp is that of pills shutting down with low RF drive on input. Because with class-C its RF only which turns on the transistors. With enough RF drive, the transformers (and capacitor) on input and output make up a tank circuit which has inertia that stores energy for the...

You must ask yourself, do I really need a low-pass filter? Tube amplifiers have a Pi-L output network, which inherently reduces harmonic output to antenna. You should never need a low pass filter with any decent tube amp. Solid state amps do need output filtering, for base-station use...

drive for a 2879 has always been 10w PEP max. Or 5 to 6watts dead key if you want some reasonable forward swing. But as you drive more pills, you have slightly larger splitter loss. So it might be reasonable to drive a 12 pill with 10% more per pill than you would an 8pill. But anyone...

sure is big difference between tarheel and hi-q. The hi-q has 10dB less loss than the tarheel.