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Tuning of the SWA 3501 or SWA 2000 antenna amplifier

copper 7617 13
This content has been translated flag-pl » flag-en View the original version here.
  • #1
    copper
    Level 11  
    Hello,
    I have a bit of a problem with DVB-T television reception.
    I have a broadband antenna on the first floor, on the balcony.
    In front of you a south block, to the left, east a block very close, to the right, west two large trees, reaching the third floor.
    I can't mount the antenna on the roof.
    Although I am about 25km from the transmitter. The cost signal without an amplifier is negligible. The AX-1000 directional antenna with balun doesn't work at all.
    However, the broadband antenna with the SWA 3501 amplifier worked and only such ...



    I give the signals that I currently receive, broken down into frequencies:
    602MHz Signal 100kW (Czech Republic) Signal quality 100 / Signal 91 varies 95/90 93/87 98/90
    698MHz 63kW signal (Polsat, TVN, TV Plus and others) 100/98 100/96
    634MHZ Signal 100kW TVP1 TVP2 overdrive signal 0/100 2/100 and in a moment it will click 100/100
    746MHz (TTV, TV Focus, Freeze Frame) The weakest signal 50kW 35/80 19/90 30/91 35/93 - weak sometimes disappears.
    I also catch 682MHz Mux L2 from Ornontowice 35/65 49/67 53/67

    For this purpose I used the tuned SWA 3501 / 4T, I will present what I changed in it.
    Resistor R2 from 210 ohms to 390 ohms (in the SWA 2000 version it is 300 ohms) and the power input for UHF from 390 ohms to 330 ohms (in the SWA 2000 version it is 470 ohms) which gives a change of the UHF supply voltage from 12V to about 7, 46V (I have 7.79V)

    I enclose the characteristics of SWA 2000, SWA 3501 and photos of amplifiers.
    Tuning of the SWA 3501 or SWA 2000 antenna amplifier Tuning of the SWA 3501 or SWA 2000 antenna amplifier Tuning of the SWA 3501 or SWA 2000 antenna amplifier
    Has any of my colleagues modified such amplifiers and could I say something about how to regulate the gain on particular frequencies? I want to raise the signal at 746MHz by about 2 dB and lower it to 634MHz by 4dB. Any ideas are welcome.
  • Helpful post
    #2
    irekr
    Moderator
    How far do you live from this chimney?
    http://old.radiopolska.pl/wykaz/pokaz_lokalizacja.php?pid=526

    Can you provide a more accurate location? At least 50 BTSs with LTE in the 800 MHz band are currently operating in Gliwice (more are coming every month). The use of amplifiers is the worst method of "tuning" antenna installations.

    Added after 10 [hours] 18 [minutes]:

    Thanks for the location info at PW.

    So we talk about Bytom and around the Provincial Hospital and the Church of the Exaltation of the Cross. On both of these objects are BTS-t with LTE in the 800 band, i.e. the use of any broadband amplifiers at the antenna is pointless. In home conditions, I see no chance for a simple amplification of channel 55 without overloading the receiver with LTE BTS signal.
    Theoretically, this is possible with the help of a good (and expensive!) LTE filter and with the use of tuned distribution amplifiers from the WWK series from Telmor. But all these solutions are expensive and the end result is unknown.

    The amplifiers from the SWA series are known for their special incompatibility with other signals. In principle, they are only suitable for use on a desert island. Not without reason, some of them (and May) were banned from selling.
    This "tuning" that you describe gives little. You will not eliminate the basic disadvantage of these devices, which are the wrong reinforcing elements. They were quite good in analogue times, but not today.

    I would, however, experiment with passive antennas. I know that the installation conditions are not good and basically you can only rely on distributed signals. However, remember that MUX3 are also transmitters in Zabrze and Bytkowo, it is not surprising that the signal is very strong and causes clipping. Additionally, there are problems with the MUX1 reception, where you have LTE BTSs in the "beret" range as well as a high channel and interfering signal from Skrzyczne (SFN, the same channel). Contrary to appearances, in Bytom the signal from Skrzyczne is quite strong, with Costs off you can receive Skrzyczne on almost every antenna.
    The use of traps for channel 41 and LTE filter may help, but there is no certainty. It will be difficult without experiments and great self-denial.
  • #3
    copper
    Level 11  
    Thank you for your answer.
    I've heard that the recall is just about SWA 2000.

    Regarding the K55 746MHz channel, I think they should not broadcast this MUX on this frequency. There are so many free channels from 474 to 602 that could be strengthened accordingly. Opole broadcasting, for example, this MUX on 674MHz.

    I am currently working with this SWA 3501 / 4T without interference at 746MHz, 698MHz, 602MHz and yesterday I even caught Ornontowice L2 682MHz, but at 634MHz I must probably launch a second antenna on LNA101. I don't download anything on the balancer itself. (634MHz Quality 0, Signal 19)

    Tell me are LNA 177, LNA 169 and ANT148 better than SWA?
    I don't have ANT148 25dB gain scheme, but it's probably the one below. Description of reinforcements on the housing.

    Tuning of the SWA 3501 or SWA 2000 antenna amplifier
  • Helpful post
    #4
    irekr
    Moderator
    It's basically the same design and the same elements. The problem is the BFR series transistors used. Just look at the intermodulation parameters - around 60 dB. There should be at least 80 dB. Good amplifiers are antitall amplifiers, on high current Gasfets, they have a completely different structure from what we have in stores. But such an amplifier does not cost $ 5 for a box of 10,000 in a Chinese barn.

    There is another one; more important problem: within 500 meters of you are several transmitters with a total power of over 1 kW on channels slightly above 61go. Any amplifier - even the one that is suitable for DVB-T - can't stand it. There are filters cutting out this range, but the better the filter, the more it costs. In principle, only those priced above PLN 100 can be used. On the Electrode you will find watts and interference from LTE.

    But this is just the beginning. You have MUX1 on channel 55. From the end of March, the process of migration to DVB-T2 and launching the so-called II digital devidend - that is, the purpose of the internet for frequencies above 694 MHz. This will mean turning off the transmitters on channels from 49go up, but also new Internet services will appear on this band ... It means that it will be worse. We will start this process soon, despite various protests.

    What can you do in your situation? First of all, using a passive antenna, I would look for a place where you have the weakest possible signal from LTE. In urban conditions this is real, sometimes you need to move the meter a meter or two sideways or up / down. Even for balcony and window installations it is possible. You will probably find something. Then there are filters and band and resonant amplifiers, e.g. from TELMOR. It may not be cheap but it gives results.
    If you receive Czech and MUX-L stations from Ormontowice, it means that the signals arrive with a sufficient level. The problem is only to level them.
  • #5
    copper
    Level 11  
    Thanks to your factual message, I described the problem of 746MHz frequency interference to Emitel. I suggested free frequencies from 498MHz to 602MHz. I know that this is not a simple transfer of the transmission channel, but at least they know the problem, because if I have a problem with the reception of K55, hundreds of Kowalski and Nowaks in a similar location do not have programs at all or have overdriven "sifting ether" amplifiers. If you want to join my petition, write to them too.
  • #6
    copper
    Level 11  
    In addition, I wanted to ask how to secure the Euro socket on the television against current surges from the antenna amplifier.

    I want to supply 12V power from the Euro socket on the television to the amplifier in the antenna through the antenna socket. For what? To cut off the antenna power supply together with switching off the television. There is a capacitor in the antenna socket, I'm not mistaken 1nF, to cut off the voltage from the TV head, it is known, but how to secure 12V in the euro plug from which I will lead 12V to the antenna plug? Zener diode?
  • #7
    irekr
    Moderator
    Almost all receivers and decoders have something like antenna power. It is sometimes marked differently, but the function is the same.
    This 12V in SCART is basically for signaling purposes and can provide at most a few mA.
    I don't think the receiver gives voltage.
  • #8
    copper
    Level 11  
    Tuning of the SWA 3501 or SWA 2000 antenna amplifier

    Blaupunkt 60cm / 23.6 "LED TV 720p - I haven't found the antenna anywhere in the power menu, unfortunately. Maybe someone will help you find or know some trick.
  • #9
    LeDy
    Level 43  
    Most TVs do not have antenna power which is logical due to possible short circuits. Besides, this is not the role of TV. The antenna is to be powered by the power supply to it.
    I find the idea with power supply unreasonable. To prevent voltage from entering the head, it is necessary to interfere with the head and add elements.
  • #10
    irekr
    Moderator
    I have receivers from three companies at home, Panasonic, Toshiba and Philips, I have several Samsung receivers in the company, they all have the power to power the antenna amplifier (and in all of them I checked if the power supply is turned off).
    The fact that sometimes this option is quite well hidden. I don't have Blaupunkt and I haven't had it in my hands lately.
  • #11
    copper
    Level 11  
    LeDy wrote:
    Most TVs do not have antenna power which is logical due to possible short circuits. Besides, this is not the role of TV. The antenna is to be powered by the power supply to it.
    I find the idea with power supply unreasonable. To prevent voltage from entering the head, it is necessary to interfere with the head and add elements.


    An antenna plug with a built-in power cut-off will be connected to the head. I will not touch anything in the TV head. I want to draw power from the euro so that I don't have an additional power supply connected to the power supply all the time when I can use the power supply from the euro socket. The problem is only to protect the euro socket against any surges from the antenna amplifier.
  • #12
    LeDy
    Level 43  
    If there is a lightning surge, it will not protect anything. Give (what is in the picture) or that the diode does not go back in series. Tuning of the SWA 3501 or SWA 2000 antenna amplifier
  • #13
    copper
    Level 11  
    I installed the SWA-7 amplifier and I must say that it works better, but at 746MHz it is still susceptible to interference. I have heard that it can be requested to UKE that the operator interfering with the 800MHz TV, repair the damage by installing LTE filters on the disturbed user. Anyone know anything about this?
  • #14
    Fotodetektor

    Level 30  
    copper wrote:
    I have heard that it can be requested to UKE that the operator interfering with the 800MHz TV, repair the damage by installing LTE filters on the disturbed user. Anyone know anything about this?

    You can report to UKE. They will come by car and take measurements. Later they will write to the operator and verify. This process will last and last ..........

    In a moment there will be another change and the 700 telecommunications band will be released. It will be a commotion. Channels 55 and 58 will disappear for me. They will go down. It will be a hug !!!