Old all band graymark radio
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Regenerative receivers were not replaced because of faulty,Įrratic behavior, such as I read in today's descriptions of them, or else they would not have Receivers and regenerative-superhets, at least on the HF bands. Oscillator as a separate circuit from the actual Mixing circuit long after pentagrid convertersĪs economic times got better, hams were better able to get into the technological strides of theĭay, with it's buffered RF stages, multi-element converter tubes, AGC, Single Signal Crystalįiltering, "Silent Cans", and all the niceties that eventually eclipsed the old regenerative This is one reason why many hams kept the Local React to the dynamics of the receiver input. The potential existed for the variable Local Oscillator to Tuning, only a few hundred KHZ from the receive frequency, much care had to be taken in it'sĬonstruction, for stability's sake. Sensitivity and selectivity at those frequencies! Since the Local Oscillator provided the It is very hard to beat a regen detector for Put to practical use the best of both circuits. This was a true superhet design incorporating a tunable first detector, generating a fixed outputĪt a very low frequency, about 100 KHZ or so, followed by a regenerative detector. Such innovation was the "Super-Gainer" receiver. Many hams to build versions of more expensive commercial devices on a Depression budget. Frank Jones came out with an "every man's" type handbook which enabled One way of upgrading the old TRF withoutīlowing the budget was to just make the converter stage and follow it with the TRF, using it asĪ variable IF tuner. Were meant to make a dollar go as far as it could. Spawned many design innovations, some of which were strokes of genius. Otherwise it might have meant the bread line. A three dollar tube could equal a week's foodĪllowance. Out of reach for the average ham of 1936. It was a financially difficult time as well, and many of these more advanced designs were just TRF type receivers were grudgingly being given upįor the more sophisticated superhets, both in the amateur and in the Broadcast industry. This type of receiver represents a period of technological crossroads, a time when old schemesĪnd philosophies were giving way to new ones.
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Most of your money will be spent on niceties like vernier dials orĪuthentic antique parts as you choose to incorporate them. Price: Since parts are not really that critical or numerous, the cost of construction These radios so far, and each one averaged two afternoons of construction time. Coils are few, easy to make, and permanent. Selectivity) thereby presenting the detector with an amplified signal.Ĭonstruction: This receiver is no more difficult to build than any two or three tube Sensitivity: The front-end provides some conversion gain ( as well as increased
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Band changing is just a matter of switching a crystal, not a coil. Tuning: The tuning rate is constant for all bands because the detector tuning range The detector is allowed to operate under a more constant load Generation, keeping varying antenna reactance from affecting the tuning and loading Stability: The detector is isolated from the antenna, greatly reducing signal With the resultant higher Q tuned circuits there is Selectivity: The detector is allowed to operate on a low frequency, where these There are many advantages to this scheme: 1 (.bmp) can best be described as an RF converter followed by a tunable On a bed-side table, plug in and GO! And, I wanted it to be as simple as the regens, But for 20 meters, I wanted something that I could throw Once bolted down and grounded and adjusted, That my two stage regenerative rigs would be especially sensitive with small antennas.īut at frequencies much higher than 40 meters, they were cranky things to tote around,Īnd required a stable operating environment. That being: my only antenna just might be a clip lead to a window screen. I missed being able to keep up with the ham activities, and I wantedĪn inexpensive yet sensitive receiver which could operate under hotel room conditions. This project was the result of living on the road as a National Trainer for a large It than your standard two or three tube 'gennie. " Blooper Nostalgia" articles again? Well. Old receiver which may surprise you in performance. Have you been wanting to make something the other chaps on the net don't have?įeel like re-inventing the wheel? Here is a rather "novel" version of a traditional Looking for something new to do with those old tubes collecting dust in the junk box?
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Contents View Photos View Circuit What is it? A Little Background Construction Notes Winding the IF Transformers Circuit Description Circuit Layout Set-Up and Operation Added Comments Helps and Resources Summary Comments