Thank you for answering Val. I was more concerned about possible signal quality issues. Nonlinearity etc. Regarding the things you mentioned I think they are acceptable to me. The plate voltage is in
I have a common cathode, tetrode amplifier with mechanical tuning memories. The way it is usually used is to tune it for the middle of the band (or in the middle of a half of a band if the band is pr
Thank you all for interesting replies. Indeed the amplifier is operated remotely or if I'm sitting next to it I still don't touch the tuning and I operate it the same as if I was remote. So the comme
I have not thought about that. Although I use a trx that applies adaptive predistortion so most likely something else would fail (likely my antenna switch) before the signal deteriorated it is a very
This explains why we (owners of this amp -it is very popular in Poland , Russia and some other countries) can get away with tuning it for let's say 3.7MHz and use it on entire 80m (which ends at 3.8M
Hi, I've recently been testing cheap Chinese vhf amplifiers to boost few tens of mW of power to a couple of watts. Each came with a warning (on a sticker, or piece of paper attached) that says "do no
Thanks Bob. Well, all but one amp are toast. The first one I powered up was the one with the RF3809 chip. I had a (well tested at high frequencies) 20dB 200w attenuator at the output followed by 30dB
I'm playing with Lime SDR. A somewhat similar device to Pluto. After I spent a couple of months using my HF SDR (Hermes Light 2) that is connected to my "big" HF amp. I wanted to have a similar exper
Thanks. $215 is not a bad price (although at the lowest drive level of 100mW I'd still need a preamp - one of these "20dB 0 to 5GHz" boards). If it was just that I probably would've ordered it by now
So I procured two more Chinese vhf amplifiers (and ordered transistors and a chip to fix the previous ones). Amongst them is one that claims 15W of heat dissipationand up to 5W of RF power with 7.2V
Hi, As I had recently chosen to give uhf a go I decided to assemble an ldmos amp kit I bought many years ago. It sat in my drawer for 5 years I found this useful website http://g4fev.atspace.com/mrf1
I've been trying to simulate the 930MHz circuit from the datasheet as a starting basis and I had to increase the trimmer by 5pf - otherwise numbers don't work.. Then it seems to work? Can someone tel
Thank you for the reply. I'll do that. It was pulling 2.3A at 24V. _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/a
I have a certain suspicion... I found one more person who described their experiences (it wad also, "put it together , got 70W, no tuning etc However , that person drew a schematic of their amp and t
Thanks Steve. I'm not sure how a watt meter is more useful than a vna in this instance. If the vna is showing me a good match the watt meter will agree. If the watt meter shows no power going in, it
Very interesting , and "VBsemi"? I never heard about this company. This datasheet reads like a different device. I saw this datasheet by co pany called "Renesas" https://pdf.dzsc.com/88888/2007121994
Well.. I thought I found the problem. One was a stupid mistake of not putting in a thick jumper in the drain supply of the second transistor in the pair. I noticed the output of the second transistor
Success at last! It turns out the trimmer I used was assymetric and the other one was overheating(I only saw that on IR video). Being located right next to gates it was messing with the symmetry. Aft
I've recently got my hands on some ancient mobile phone base station amplifiers which I've managed to retune to 435Mhz +- 5MHz but I need some help with choosing the voltage to run them at. Does anyo
Thanks for the reply Ron. I've retuned it for our 70cm... The original frequency was claimed by the seller to be 450MHz. But it was actually 460MHz. 430 to 440MHz is the European 70cm band. That's wh