CB servicing on a shoestring budget (UK) - RX on cheap Chinese FM signal generator 

I covered tx on a budget last year!

My first signal generator was a huge schlumbeger FS30 & FSM500 solid state synthesised I recall paying £1K for it.....bearing in mind I'm from a professional business radio backround, that was about the cheapest I could find. Sold it on in the 90's to a radio amateur

Yes that's fine. Email me. rshireby@yahoo.co.uk

sine wave only. Richard

I didn't know there was a TX mode as it's just a signal generator. They do another that does TX. MR Chippie has one of those smartphones (I have a rotary dial house phone). There is some translate software program you can put on smartphones so that when you hold it's camera to foreign writing, it instantly translates it onto the screen in real time. When we bought this signal generator the aliexpress advert had basic instructions in english on the advert as it said there was no instruction book. If I were you, I'd find info in Chinese on it & translate it. I'm sure you'll find what you need to know that way, Richard, G0OJF

Yes. It needs to be a sine wave for radio. The generator also has to be able to produce a modulated tone on the signal. This one is FM only which is why I featured it. Many cheap generators are AM only. Obviously the generator has to produce the frequencies you need. No point buying a 10Mhz generator of you want to tune radios at 27Mhz. Richard, G0OJF, UK

@@ukfmcbradioservicingTango21 copy that. Thank you.

Sorry, this was a 'one off' demonstration of how I used this cheap signal generator. You will need to research a copy of the instrictions or the signal generator for your answers. I would expect V17.9 on the display to mean the firmare version to be "Version 17.9". Richard, G0OJF, UK

Sorry, I've no idea. Richard

It depends what country you are in for a start. I only deal with repairs of business 2-way radio, but also am happy to service UK legal CB radios as well for the trade. The best new CB we have serviced & tested this year was the Thunderpole T3000. Amplifiers are illegal in every country I am aware of. Seeing it is an illegal market, they all seem to be pretty poor from what I've seen before chopping them up. Mobile aerials, the SIrio performer 5000 was the best mobile aerial we've tested to date....base station we just use 18' 1/2 end fed aerials of no particular brand & they all work 35 miles in our 'good' direction using UK 4W FM cb radios. I just demonstrated the cheapest SWR meter I could find from CRT & it worked OK on that video demonstration. As a radio engineer, most of our business customers are on VHF high band or UHF systems, so I have to have different meters depending on what I'm doing. I'm not a big brand person. Many expensive products I've owned over the years turned out to be c**p, and on the other hand, cheapo power tools from ALdi & Lidl have worked a treat! Richard, G0OJF

@@ukfmcbradioservicingTango21location Belgium

For a start, there are three 220uF electrolytic capacitors on the main board: they all need replacing. Now these sets are 36+ years old they are knackerd....even on a brand new unused set. I recall they are 16v rated, so replace them with the next voltage up...something like 25 or 35v for improved reliability. These capacitors smooth the various voltages used within the radio. Everytime I have a radio in with the Uniden board, I always change all three even if they aren't 'yet' showing as faulty. Don't forget to replace them with the polarity the right way round! Richard

UK CB radio servicing Hi Richard I have got my uniden uniace fully working now sort of on eBay I purchased a donor rig that was absolutely destroyed but still functional serial numbers were only 350 apart so I transplanted the board from the broken beaten up CB into my also broken but brand-new in box version and now have one perfectly functional radio that is in great condition, my only problem is the signal meter is not working the polarity is correct, the bulb lights , but the dial doesn’t move is there any chance of a wire could of fallen off inside from soldering?

You can check the meter with your multimeter for continuity & if the radio's meter appears ok it is possible for a wire to have come off.However, I would expect the meter itself to be duff as the internal wires are hair thin. Bear in mind you need to ensure those 220uf capacitors are changed or you will have a non working set pretty fast.

No, It's preset.

yes you can

Thank you for replying sir.

Yes...

The model you mentioined isn't a UK approved CB radio so I have no specific advice. Generally though.....it sounds like when you draw beyond about 1A of current the radio malfunctions. First you need to check the power supply voltage is still what it should be when in transmit of higher power. If that's OK, the radio has an internal fault. Richard, G0OJF, UK

@@ukfmcbradioservicingTango21 Ok , thanks for info !

I've never seen one under £400! Very well done

I've never heard of one. Without me researching it sounds like a computer based thing. Richard

@@ukfmcbradioservicingTango21 It's a £50 spectrum analyser which is phenomenal which also has a built-in signal generator with various modes of modulation. A very similar product to a nano VNA. I've used mine to align / repair a few radios and it does the job well. The things are amazing!

Sorry. but as the ,main business here is in church pipe organ restoration, we are booked up until at least April 2020 so no videos are possible....unless it's about pipe organs! Richard (UK)

@@ukfmcbradioservicingTango21 and here I thought I'm the only bloke who dabbles in Gedackt, Vox Humana and product detectors at the same time...😇

@@mooiwiele Ah well, I have three parallel careers each of 40 years...Church Organ Builder, Church Organist, Electronics engineer specialising in 2-way radio. Richard (UK)

Without even looking up the frequency coverage, bear in mind this is FM only it is rare for amateur radio to be FM lower than 29Mhz. There are plenty of cheap AM signal generators around...it's FM that's hard to find, hence this video. Note that UK CB is FM. Richard (UK)

AM generators are cheaply available. This is FM only.

I'd not heard of it so I looked. As a licensed radio amateur it would cost me $39 for a non-commercial slimmed down version. Next snag....no room for computer on bench. Considering I paid £20 for one of the Marconi SINAD meters & £45 for another it seems cheaper & obviously better to buy a secondhand real SINAD meter that one cost someone £800+. Have you noticed the main test sets here are Marconi 2951 from the 80's? We also have a Farnell test set of similar vintage & a Schlumberger 4040. Why don't we have a Marconi 2955 or similar? The answer is Latency. I really don't have the time for ...adjust ...wait...adjust..wait etc. I want INSTANT meter readings. That's why you see the BRAND NEW this year CRT oscilloscopes on the bench too. A bit like these new CB radios where you press the PTT & then wait 1/2 second for the CPU to go into TX! Thanks for bringing this to my attention though. Bear in mind you still need a signal generator with a meaningful attenuator to provide the signal for tuning the radio with. Richard, G0OJF

@@ukfmcbradioservicingTango21 Awesome thanks for that reply I had not noticed it was licensed software thought it was free, oh well. Yeah latency is a pain I like things instant too. You have some great test equipment there by the way and I love your videos 73 for now de 2E0LIG

Karl, No. I must do so & let you all know. Richard

UK CB radio servicing you are the only guy having this on youtube hope you do a review on it, i ordered one so i can align vhf uhf repeater front ends to specific freqs.

No, it's FM only. Richard, G0OJF, UK

Presumably shows the internal firmware version. Richard

I wonder what v0.1 was like?

This channel covers UK legal CB radios. The DX2547 isn't a UK legal CB radio so I know nothing. Richard (UK)

Youre saying this would properly work on a AM CB radio as I have many of them that could use a receive alignment. Did you just use a BNC to PL259 cable and go right to antenna jack on radio and go through alignment procedure on on Ch 19? Will it cover channel 20 as well can you input your own Mhz???

Nicholas, this signal generator is FM only so is NOT suitable for AM or SSB alignment. Richard (UK)

On Aliexpress.com there are three 'adjustments' top right directly under the very top advertising banner. There is 'ships to' and you set that to your counry, there is currency (mine is set to BP) and then there is Language. Between those three you should be able to set everything up & it'll remember next time you use it. Payment is by debit/credit card, alipay (like paypal, but there version) & Paypal too. I've been buying off there for a good 5 years. Richard

@@ukfmcbradioservicingTango21 Thanks Richard :)

Sorry, I can rarely comment on test equipment videos like this as these kind of items are usually sold on after the videos are uploaded. Our Mr Chippie has one of those smart phones (I don't do mobile phones). Mr C has some translation software on his phone that allows you to point the phone camera at foreign writing & it instantly translates onto the phone screen. When we get stuck over lack of Chinese instructions in English, he goes onto the original sales page (such as AliExpress) & is usually able to read the Chinese full instructions. Perhaps that could work for you. Richard

​@@ukfmcbradioservicingTango21 Thanks for the reply. This device is really interesting. My unit has no model number whatsoever on the case and does not come with any manuals but works well for what it is. The seller item description contains nothing useful either. On my unit (firmware version 20, newer than yours) the modulation frequency can be changed to "/"K (actual slash, not a typo). I think this is a bug. The attenuation only goes as far as -70dBm like what you mentioned. The LCD only displays "dB", probably due to lack of characters. They might as well remove the R and show "dBm" in full.

@@mdanh2002 That second line is CTCSS, You can set it to modulate CTCSS tones with the up down buttons, if its on zero its doing nothing, these are useful and cheap little generators while they work, mine only lasted a couple of months, I was very careful with it never transmitted in to it etc, just used it to align CB radios, it started losing signal really badly, getting weaker and weaker until nothing comes out of it now, you would be better getting a more expensive sig gen and a dbm switch box, to get an fm signal generator that will level to 0.1 micro volt over 20mhz is very expensive even second hand, these are cheap junk really I wouldnt recommend them to anyone.

​@@knoxieman Thanks a lot for the info! Now I know it refers to CTCSS. You are right these units are built down to cost with absolutely no quality control whatsoever. No output protection as well so don't connect the wrong thing to it. My device also has some other weird bugs. After changing the frequency a few times, the display will be garbled with strange characters, e.g. "R278IG" (with alphabets) - to recover you must reboot. With regards to the output RF power level, I am experiencing the same behavior on my unit. When I first got it, I was able to analyze the output and see the RF peaks using FFT on my HP 54615B 500MHz oscilloscope. But after a few months I am no longer able to tell the peaks from the noises in the FFT view. The output can still be detected with the TinySA spectrum analyzer. I think the output power of the unit has decreased like what you said (the oscilloscope FFT is less sensitive than the TinySA). The device is still useful for aligning radios. I hope it won't die totally any time soon ...

@@mdanh2002 really the best option for accuracy is to go for a quality second hand lab set, these units are very poor, great idea but needs work, the boards inside this thing are held in with hot glue, if you can't trust your test equipment there is no point in using it, you would be better leaving the radio as it was, I'm on a budget so can't afford to pay silly money for old gear with no calibration certs that might not work, I'm looking at a kmoon Sig Gen and a digital step attenuator, most of those cheap Sig gens don't drop below 1 mv which is too much signal for fm receivers, with an attenuator you can drop it down and work out the dbm signal level, if the kmoon doesn't modulate a 1 khz tone ( I think 600hz is max internally) you can inject one via bnc, that's the option I'm looking at, I'm interested to try the digital step attenuators, 30 quid to to 30db . This unit is going in the bin now sadly, Richard did the right thing selling it on.

What kind of numpty transmits power into such an item. On a serious note the ARRL handbook always has 'sniffer' type attenuator designs that can be made cheaply.

i was connecting it to the RX filters on a cavity unit, connected the TX by mistake and the radio sent it's ident at the same time, school boy error, learn to switch off first.. i have got an RF sampler as well hooked up to the scope and counter as well.. oh well easy come easy go..

Best using an analyser with a tracking generator with no transmitter in sight. Richard

Unfortunately the Superstar 360 is not showing on my list of UK legal cb radios, so on this occasion I am unable to help you, Richard

No, it is solely for FM Richard

email me & I'll email it back to you. rshireby@yahoo.co.uk

Only if it generates the frequency you want & that you can attenuate Richard, G0OJF

Not at present...it'll be a good couple of years before we sell any duplicate serviced samples. Some of the 1981 sets like the York 861/rotel 220/ Harrier CB have really stood the test of time & are still worth buying second hand. Richard

Thanks for the info and the speedy reply

no, it's fm only.

What is a decent cheap one for AM Cb radio band

Near Ancaster in Lincolnshire to answer your question, but service is only provided for UK legal radio equipment. The (zodiac) Osaka is not a UK legal radio & looking at Zodiac's website it seems a long discontinued model as I can't find anything about it. Richard

I started 4 different videos & three look to have long term snags whilst parts come from the far east. Good news is I have a Team 8000 80ch base station on the bench & part one (repair & tx) is nearly in the can. Rx will not take long, so with any luck the 'on the air' could well get recorded tomorrow afternoon (sunday). Glad to see you look forward to my bulls**t free input! Richard

@@ukfmcbradioservicingTango21 I like to see how all the different radios perform on test. I have a rotel rvc240 myself which I use static mobile sometimes and have had contacts over 20 miles away from where I live. Mr chippy and zx2 must be getting bored as they've had no road tests for a while 😁

Well we do ham radio things too most weekends & were range testing 4 Metre (70mhz) equipment last weekend. Richard

Your CRT 2000 should still be under warranty. What's the snag with it? By the way, I sit on UK channel 31 when out & about. Some Grantham breakers are in range from here too...I'm near Ancaster in the middle of nowhere. Richard

Thanks for the reply. I got it from from a chap so don't think it will be . It's not powering on. So thinking it's blown power . Hope you can help.

Be aware that there is no service manual (yet?) for this model so anything not obvious can't be done. Email me please rshireby@yahoo.co.uk

No. In countries where there is AM CB, much cheaper & simpler signal generators can be used. Richard, G0OJF, UK

that would relate to 50uV & is indeed specified for some CB radios, probably to make them look more sensitive than they are. The correct standard is 100uV for S9 (-67dbm). Note, this applies to UK legal CB radios. Amateur radio has different settings which we are not involved with & business radios don't have meters. Richard (UK)

@@ukfmcbradioservicingTango21 I just realised the video is on CB and any signal testing I've watched demonstrated is on amateur radio. Learned something new. Good test unit considering most options are in the $1000's Cheers.

@@ukfmcbradioservicingTango21 can anyone give me a bit of advice please, I have purchased a signal generator which covers 1-60mhz. It also has a frequency counter built in but it says max20v input on the counter. Does this mean I can only use devices that run below the 20v. Ie cb would be fine to plug into the counter due to it running on13.8v. I know probably sound a daft question. I haven't got a clue and any advice would be gratefully received. Thanks 73s Mike. P. S.. I have readed the manual nothing listed...

@@smithySalford Max volts is nothing to do with how the product is powered, but the RF voltage from a transmitter that may be applied before the frequency counter is damaged. 20V works out at just under 1W of RF power, however I would not dare go more than half of that. You normally use a 20dB attenuator 'sniffer' and connect your transmitter to that & the sniffer to the frequency counter. www.electronics- notes.com/articles/basic_concepts/decibel/dbm-milliwatts-volts-conversion-chart-table.php is worth looking at. I recently bought a 20dB sniffer via ebay from Italy for about £40 as I couldn't be bothered to do the research to build one. rshireby@yahoo.co.uk Richard

@@ukfmcbradioservicingTango21 thanx Richard. I have purchased all the servicing on a shoestring gadgets of the videos. I just fancied one of them other generators for the bench I'm making up. Thanx for the information&videos and I will read up on the link you posted..

Not on UK FM CB it doesn't....that would equate to 50uV. S9 = 100uV on UK CB which in turn is -67dBm. Richard, G0OJF, UK

Think this can piece of equipment can be used on AM CB? Mostly 27mhz.

@@N64player1996 No, it's FM only. AM signal generators can be bought very cheaply secondhand; I bought one via Ebay for £10 in working order for entertainment radio alignment. Richard, G0OJF, UK

@@ukfmcbradioservicingTango21 could you provide a name of one so I could look for one.

Not everyone can buy cameras just like that. The camera in use on this video was around £1K in the early 2000's, if it broke, I'd be back to b&w videcon cameras. I work for the Church of England & money is tight. Richard