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KPA500 RF Power Monitor/Remote: KPA500 RF Power Monitor — Real-Time OLED Display for Elecraft KPA500

Six critical parameters, always visible, updating 10×/second on a high-contrast 256×64 OLED. No menu cycling. No squinting.

Monitors: Power Output (0–700W) · PA Voltage · PA Current · SWR · PA Temperature · Band + Operate/Standby

3×2 grid layout — large fonts sized for quick reading across the shack.

Direct RS-232 integration via MAX3232 — no amplifier modification required.

Specs: XIAO ESP32-C6 · SSD1322 256×64 OLED · 9–14.8V DC · 100mA · 10 Hz update rate · 4″ × 2″ × 4″

Bonus: Built-In WiFi for remote use — web interface mirrors the OLED with a retro green-on-black aesthetic, updated via WebSocket. Includes Power, Operate/Standby, Fan Speed, and Band controls plus OTA firmware updates. Access via kpa500.local — no app required. OLED operates independently of WiFi at all times.

Includes: Assembled & tested unit, DC power cable, RS-232 cable, quick start guide.

--$229 plus $10 shipping; Listing #1768320 - Submitted on 05/17/26 by Callsign KV5J, Modified on 05/22/26, Web Site: http://www.kv5j.com - IP: mobile-107-77-197-22.mobile.att.net; Click to Contact -- Click Here to View Picture -- Send this Ad to a Friend
SPE 1.5K V2 HF Amplifier: PRICE RESUCED: SPE 1.5K V2 Amp in excellent condition. Works perfectly and has full legal output. Final recently replaced and fully calibrated by Power Electronics in Florida. Cosmetically perfect - no scratches or dents. Wired for 220V but plug can be changed to 110v (with reduced output power). Complete with SPE carrying case and shipped in original packaging. $3600 includes shipping and insurance to continental US. Accept Venmo, Zelle or PayPal (buyer pays 3% fee for PayPal); Listing #1768088 - Submitted on 05/15/26 by Callsign K2KXK, Modified on 05/22/26 - IP: syn-075-190-074-087.res.spectrum.com; Click to Contact -- Click Here to View Picture -- Send this Ad to a Friend
Mercury IIIs AMP For Sale: 1kw solid state amp. Works as it should. Used as a back up amp. I have 2 of them and never a fault. So reliable, I am selling the back up. Paypal F&F. $2700. Cell: 785-554-5561 73, Morgan NJ8M; Listing #1768810 - Submitted on 05/22/26 by Callsign NJ8M - IP: 99.35.245.11; Click to Contact -- Click Here to View Picture -- Send this Ad to a Friend
WTB Heathkit SB-230: Any condition, any state. Working, modified, unmodified, dead or alive. If you’ve got one and want to part with it, let me know. Fair price paid based on condition/state. Photos a must if we get past the preliminaries. My info good on QRZ but please use the QTH contact system for the initial contact, I will not respond to direct emails due to scammers.; Listing #1768792 - Submitted on 05/22/26 by Callsign K3EMI - IP: pool-100-14-103-26.phlapa.fios.verizon.net; Click to Contact -- Send this Ad to a Friend
Vacuum high voltage capacitors: Hi everybody!
I will sell vacuum capacitors according to the following list and
contractual prices close to the prices of the store for each item
and even lower ~30$US each.
Payment on Pay-Pal ut5rp at te.net.ua
With questions about price, payment and
forwarding by e-mail or phone/Viber +380 67 699-17-05
25pF x 15kV 2pieces
50pF x 15kV 3piece
Thank you for reading the ad and a possible purchase for
offered price.
73's de Dmitry UT5RP since 1959; Listing #1768782 - Submitted on 05/21/26 by Callsign UT5RP - IP: 188-163-101-191.broadband.kyivstar.net; Click to Contact -- Click Here to View Picture -- Send this Ad to a Friend
Relays REV-15 75oHm 1500watts to 650mHz: Hi everybody!
Selling absolutely NEW REV-15 relays factory packed at a price of $30 per one. Number of relays (more than one or four together) weighing up to 1Kilo parcel shipping costs will be ~25$(to U.S.A.) by Nova Poshta, with insurance and tracking number. Relays absolutely new, working voltage is 24-27Volts, 75oHms, supports 1500 Watts of power until 650MHz, minimal life 12 years when working in any device. There are needed number of new relays for sale. When purchasing a quantity (more than 5 pieces), a discount is possible by agreement. Payment on Pay-Pal ut5rp at te.net.ua Discount is possible! All questions buying and payment by E-Mail or tel/Viber +38 067 699-17-05 Thanks for reading ad and for a possible purchase for offered price. See my other ads.
73's de Dmitry UT5RP; Listing #1768781 - Submitted on 05/21/26 by Callsign UT5RP - IP: 188-163-101-191.broadband.kyivstar.net; Click to Contact -- Click Here to View Picture -- Send this Ad to a Friend
WTD AMERITRON AL572B AMP PARTS: Looking for parts for this amplifier.
Please respond to my email address only, Thanks; Listing #1768691 - Submitted on 05/21/26 by Callsign WA0ELW - IP: 115.sub-174-229-177.myvzw.com; Click to Contact -- Send this Ad to a Friend
Tokyo hy-power: Tokyo hy-power hl 1.5kfx for sale $2500; Listing #1768690 - Submitted on 05/21/26 by Callsign KN6RS - IP: syn-047-006-191-179.res.spectrum.com; Click to Contact -- Click Here to View Picture -- Send this Ad to a Friend
RF-POWER ( RF2K-S ) Amplifier: I am selling an RF-Power amplifier (rf2k-s) brand new, unused. I bought it and I have never used it, it is brand new, very new. Currently ordering it online is taking time and it is around 6350.00 USD. I have it brand new, unused, and I am selling it for 5500 shipped. Please no scammers, the equipment is new, never been used.; Listing #1768645 - Submitted on 05/20/26 by Callsign KB4EC - IP: c-75-74-160-57.hsd1.fl.comcast.net; Click to Contact -- Click Here to View Picture -- Send this Ad to a Friend
TOKYO HY-POWER HL-45B 160-6m Amplifier: Perfect condition boxed as new original accessories, and paperwork
Great for the Yaesu FT-817/818, Icom IC-705 or any QRP radio
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$375 plus shipping; Listing #1768398 - Submitted on 05/18/26 by Callsign W8UAB, Modified on 05/20/26, Web Site: https://swap.qth.com/search-results.php?keywords=W8UAB&fieldtosearch=Call - IP: 104-169-198-75.bng02.nrwl.oh.frontiernet.net; Click to Contact -- Click Here to View Picture -- Send this Ad to a Friend