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Unitra Klaudia rms 801 Radio: Tuning Issues, VHF Range, Capacitors, BF195 vs BF215 Transistors

rocketman19 8694 12
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  • #1 16670852
    rocketman19
    Level 10  
    Hello :) I dug up my parents' old wedding gift at home, that is, as in the topic of radyjko Unitra. He is 100% running (everything works) and he plays beautifully and he is already old :) . Well, due to the fact that it works on the old VHF, I wanted to tune it, so I covered the capacitors as it was in this post:

    https://www.elektroda.pl/rtvforum/topic1811090.html

    and, as always, there must be some stairs :P

    1.Radio receives on the new VHF but I have a literally marginal range of regulation, as I look at the stations it is about 5Mhz.

    2. and I have some different elements used than in the diagrams. I mean the transistors and coils in the head. There are BF195 everywhere in the diagrams, and I have BF215 (I do not know if this is a problem), and as for the coils, they are different (adjustable) than in the photo from the post above




    I tried to adjust something with the coil and trimmer, but only managed to get a slight shift of the range by about 3Mhz up or down. Reception is only in the lower VHF range. I managed to catch RMF`FM (92.9) radio Maryja, radio family and some other stations in my area (Wrocław)


    Would some good soul help with advice and experience in such treatments?

    greetings :)
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  • #2 16670902
    Radiokiller
    Level 30  
    Hello
    You chose a buddy "recipe", which did not know how it ended.
    I propose to write to the author of the topic at PW, whether he was successful, or should you choose a different path.
    What did you measure this 5 MHz?
    Greetings.
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  • #3 16671287
    rocketman19
    Level 10  
    Before starting the action, of course, I did more research than just this one post, and in each recipe there was the same scheme for replacing and removing capacitors capacitors.

    After the radio stations.
  • #4 16671501
    Olek II
    Moderator  
    Set the scale to about 88 MHz, you set the frequency with the L305 core, then around 108 MHz, with the C315 trimmer (next to the L305). Repeat this procedure several times. Sensitivity on 88 MHz L302, on 108 MHz C306, also repeat a few times and it has to be, do not unwind the coil, stretch it a little.
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  • #5 16671556
    Radiokiller
    Level 30  
    There will be time for tuning. I think that the author's scale is too "narrow" and the whole VHF band does not fit there.
    I propose to reduce some capacitance parallel to the heterodyne coil. I had a similar problem but the opposite and I had to increase the capacity. A frequency meter would be nice, even one from an old car radio - 10 minutes of work and how useful.
  • #6 16671602
    rocketman19
    Level 10  
    Well, there will be a problem with stretching the coil. In this post, what I gave in the photo is an ordinary coiled wire and for me this coil looks like L305? (the one from the regulation) so I would have to desolder it and screw the new one.

    Added after 1 [minutes]:

    Olek II wrote:
    Set the scale to about 88 MHz, you set the frequency with the L305 core, then around 108 MHz, with the C315 trimmer (next to the L305). Repeat this procedure several times. Sensitivity on 88 MHz L302, on 108 MHz C306, also repeat a few times and it has to be, do not unwind the coil, stretch it a little.


    That's what the problem is with. I can't catch any further frequency.
  • #7 16671620
    Radiokiller
    Level 30  
    Apparently you have a coil with a core. Just a different head design.
    Combining with unwinding coils is the last resort - I know what I am writing. Wait for the other ideas to run out.

    Try treatment with # 5
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  • #8 16671660
    rocketman19
    Level 10  
    Exactly. It has an adjustable core and it does not change anything whether it is in the coil or there is no change in reception.

    Added after 2 [minutes]:

    Old car radios will be found :) I even have some stumbling blocks around the electro maneli. If you have any idea how one could help, no problem.
  • #9 16671776
    gumisie
    Level 43  
    Hello.
    You tried by. this description?
    Greetings.
    Attachments:
    • przestrojenieklaudiarms801.pdf (82.8 KB) You must be logged in to download this attachment.
  • #11 16674623
    rocketman19
    Level 10  
    Thank you very much for all your help. Unfortunately, the topic is suspended for a week because I am going on vacation. When I come back I will continue the topic.

    greetings :)
  • #13 16694672
    doktorek
    Level 19  
    Hello..
    Try it out
    Replace C301 (120p) with 68p, C302 (82p) with 47p, C303 (47p) with 27p, C310 (56p) with 39p, C318 (2p2) with 1p. Remove C305 (27p), short C317 (75p). Unwind 4 turns from the top of the L305 and move the tap 2 turns down.

    greetings..
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Topic summary

✨ The discussion revolves around tuning issues with the Unitra Klaudia rms 801 radio, specifically regarding its VHF range and the replacement of capacitors and transistors. The user reports a limited tuning range of approximately 5 MHz after modifying the capacitors as suggested in a referenced post. Various responses suggest methods for adjusting the radio, including tuning the L305 core and using trimmers C315, C306, and L302 for sensitivity adjustments. Some participants recommend replacing specific capacitors (C301, C302, C303, C310, C318) with lower values and removing others to improve reception. The use of different transistors (BF195 vs. BF215) and coil designs is also discussed, with suggestions to avoid unwinding coils unless absolutely necessary. The user plans to revisit the issue after a vacation.

FAQ

TL;DR: To retune a Unitra Klaudia RMS 801 to the 88–108 MHz FM band, align the low end at 88 MHz with L305 and the high end at 108 MHz with C315; “Set the scale to about 88 MHz.” [Elektroda, Olek II, post #16671501]

Why it matters: This FAQ helps DIYers fix narrow tuning, align VHF endpoints, and choose capacitor/transistor tweaks without guesswork.

Quick Facts

How do I fix a Unitra Klaudia that only tunes about 5 MHz on FM?

Your tuning scale is too narrow. Reduce effective oscillator capacitance and realign endpoints. Start at 88 MHz with L305, then set 108 MHz with C315. If the span stays ~5 MHz, lower parallel capacitance at the heterodyne coil, then repeat alignment. [Elektroda, Radiokiller, post #16671556]

Which adjustments set the low and high ends of the FM band?

Set the low end (≈88 MHz) by turning the L305 core. Set the high end (≈108 MHz) with the C315 trimmer beside L305. Recheck and iterate for best tracking. [Elektroda, Olek II, post #16671501]

What parts control sensitivity at the band edges?

Peak sensitivity near 88 MHz with L302, and near 108 MHz with C306. Alternate between these and the endpoint alignment for balanced gain across the band. [Elektroda, Olek II, post #16671501]

Is it normal to find BF215 instead of BF195 in the VHF head?

Yes, some heads were built with different transistors and coil forms. Proceed with alignment; part labeling differences do not prevent successful retuning. [Elektroda, rocketman19, post #16670852]

What capacitor changes have worked for full 88–108 MHz coverage?

Test this set: C301 120p→68p, C302 82p→47p, C303 47p→27p, C310 56p→39p, C318 2p2→1p; remove C305 27p; short C317 75p. Then align 88/108 MHz. [Elektroda, doktorek, post #16694672]

Should I unwind the oscillator coil to expand coverage?

Treat coil rewinding as a last resort. Try capacitance reduction and proper alignment first. “Combining with unwinding coils is the last resort.” [Elektroda, Radiokiller, post #16671620]

How can I measure the local oscillator without lab gear?

Use an old car radio or simple frequency display as a counter. It takes about 10 minutes to rig and gives quick heterodyne checks. [Elektroda, Radiokiller, post #16671556]

What if turning the coil core does nothing to reception?

If the core changes nothing, suspect wrong capacitance values or a different head design. Verify the trimmer and cap swaps first, then repeat alignment. [Elektroda, rocketman19, post #16671660]

Give me a quick 3‑step alignment for 88–108 MHz.

  1. Set dial to ≈88 MHz and peak the station with L305.
  2. Set dial to ≈108 MHz and peak with C315.
  3. Optimize sensitivity: 88 MHz with L302, 108 MHz with C306; iterate steps. [Elektroda, Olek II, post #16671501]

What’s a heterodyne coil and why adjust its capacitance?

The heterodyne coil is the oscillator tank in the FM head. Its inductance and parallel capacitance set tuning span. Reducing parallel capacitance widens the band so the full scale fits 88–108 MHz. [Elektroda, Radiokiller, post #16671556]

Any proven inductor tweaks when caps alone don’t reach 108 MHz?

If alignment and cap changes still miss the top, unwind about 4 turns from L305 and move the tap 2 turns down, then realign. Use this only after cap fixes. [Elektroda, doktorek, post #16694672]

Where can I read a walkthrough for this exact Unitra head?

See the shared guide thread for practical retuning tips and photos specific to similar heads. It complements the alignment steps here. [Elektroda, Radiokiller, post #16671865]

My receiver only gets lower VHF stations like 92.9 MHz—what does that imply?

Your oscillator tracks the lower band, so the high‑end capacitance is too large. Reduce it and repeat the 88/108 MHz alignment to span the full band. [Elektroda, rocketman19, post #16670852]

Any edge cases that can cause persistent misalignment?

Mismatched head designs with adjustable cores can behave differently. If the core type differs from guides, prioritize cap changes before mechanical coil work. [Elektroda, Radiokiller, post #16671620]

What’s a trimmer capacitor in this context?

A trimmer is a small adjustable capacitor used to set the high‑frequency endpoint. In this radio, C315 trims the 108 MHz alignment point. [Elektroda, Olek II, post #16671501]

Can I pause the project and resume later without losing progress?

Yes. Document current cap values and core positions before pauses. On return, repeat the 88/108 MHz alignment loop for consistent results. [Elektroda, rocketman19, post #16674623]
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