27 MHz vs. 75 MHz

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Basher67
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27 MHz vs. 75 MHz

Post by Basher67 »

I've been going through the piles of old radios and receivers I have laying around and came up with a nice Airtronics XL2P transmitter that is 27 MHz. After looking through all my receivers, I realized that I have over 40 in the 72 and 75 MHz variety and no 27 MHz. Is this just an anomaly that occurs in my hobby room or was 27 MHz less popular? I seem to remember all my radios bitd being 75MHz, but sometimes my memory ain't so accurate. I remember that the cheap toy grade rc's were sometimes available in 27 and 75 MHz frequencies instead of different channels on the same frequency. These days, discussing radio frequency seems to be a dead language, but the old radios still have their place now and then within the vintage rc world I think.

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Re: 27 MHz vs. 75 MHz

Post by Incredible_Serious »

From a non-US point of view, here in Convict Central we used mainly 29MHz and 27MHz for cars, with 40MHz also available. 72MHz / 75MHz were forbidden, as one of those frequencies (not sure which one exactly) was used by emergency services.

I think 27MHz was available in most of the world's markets, which unfortunately meant a lot of toys were on 27 as well.

Not sure if too many other places utilised 29MHz, other than us.

Of course, there were 30 channels each available for 72MHz and 75MHz, as opposed to only 6 channels for 27MHz.... I would say that was a major factor, in a place like the US, with so many enthusiasts.

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Re: 27 MHz vs. 75 MHz

Post by jwscab »

Yeah the FCC or it's equivalent in each country split up the rf spectrum and allocated it to specific purposes. 75 Mhz was popular in the US as well as 27Mhz. 72 is also used but it's for aircraft only. I think 27 may have been available for surface or air? It's a bit fuzzy. There are charts you can Google that show you how the spectrum is split up.

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Re: 27 MHz vs. 75 MHz

Post by GoMachV »

27 was worldwide air and ground. USA only got 6, but I thought there were 12 total?
72 started as air and surface (a few upper channels switched to air only when 75 came around)
75 was most popular in the USA
50 and 53mhz was a ham band and if you had a license it was a great way to avoid problems at the track
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Re: 27 MHz vs. 75 MHz

Post by Incredible_Serious »

GoMachV wrote: Mon Feb 05, 2018 10:04 pm 50 and 53mhz was a ham band and if you had a license it was a great way to avoid problems at the track
I hear they were only for Kyoshos, because they drove like pigs......
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Re: 27 MHz vs. 75 MHz

Post by makoman1860 »

Basher67 wrote: Mon Feb 05, 2018 9:05 pm I've been going through the piles of old radios and receivers I have laying around and came up with a nice Airtronics XL2P transmitter that is 27 MHz. After looking through all my receivers, I realized that I have over 40 in the 72 and 75 MHz variety and no 27 MHz. Is this just an anomaly that occurs in my hobby room or was 27 MHz less popular? I seem to remember all my radios bitd being 75MHz, but sometimes my memory ain't so accurate. I remember that the cheap toy grade rc's were sometimes available in 27 and 75 MHz frequencies instead of different channels on the same frequency. These days, discussing radio frequency seems to be a dead language, but the old radios still have their place now and then within the vintage rc world I think.
What ya got for 72mhz receivers???? :mrgreen: :mrgreen:

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Re: 27 MHz vs. 75 MHz

Post by GoMachV »

Incredible_Serious wrote: Mon Feb 05, 2018 10:08 pm
GoMachV wrote: Mon Feb 05, 2018 10:04 pm 50 and 53mhz was a ham band and if you had a license it was a great way to avoid problems at the track
I hear they were only for Kyoshos, because they drove like pigs......
:lol:
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Re: 27 MHz vs. 75 MHz

Post by Basher67 »

I pulled these two off the top of the first box. found a 27 mhz one while I was looking too. :lol: I may have underestimated how many I have. :lol: Why a 72 mhz? Aren't they comatible with all the 75 mhz stuff?
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Re: 27 MHz vs. 75 MHz

Post by GoMachV »

No 72 and 75 aren’t compatible
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Re: 27 MHz vs. 75 MHz

Post by Incredible_Serious »

Basher67 wrote: Mon Feb 05, 2018 11:19 pm I pulled these two off the top of the first box. found a 27 mhz one while I was looking too. :lol: I may have underestimated how many I have. :lol: Why a 72 mhz? Aren't they comatible with all the 75 mhz stuff?
Love these pics.... I find them very familiar.... this was last week for me.
Receivers.JPG
Can never have too much junk.... unfortunately... :oops:

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Re: 27 MHz vs. 75 MHz

Post by RC10th »

27 as far as I remember was pretty much compatable across the whole range, didn't matter what brand as long as the frequency was the same.

75 was when things went to narrow band and cross branding usually didn't work. Futaba -Futaba or JR -JR was fine but Futaba - JR was a no go.

Then there was 27 and 75 FM which had far less interference then the AM counterparts and 75 PCM was the best you could get
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Re: 27 MHz vs. 75 MHz

Post by RC10th »

Ooooo, I spy a JR135 FM receiver in your stash and a synthesized JR but too bad they're 40mhz, those synthesized jobbies and modules were the ants pants back in the day.

I found this in my stash of stuff for some reason. It shows the twelve 27mhz AM crystals that Jeff was talking about, there were 6 typically but you could get halves. The 29 is foreign to me, it's like speaking Chinese.
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Re: 27 MHz vs. 75 MHz

Post by makoman1860 »

Basher67 wrote: Mon Feb 05, 2018 11:19 pm I pulled these two off the top of the first box. found a 27 mhz one while I was looking too. :lol: I may have underestimated how many I have. :lol: Why a 72 mhz? Aren't they comatible with all the 75 mhz stuff?
You ever want to part ways with any 72 stuff, you let me know :mrgreen:

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Re: 27 MHz vs. 75 MHz

Post by Incredible_Serious »

RC10th wrote: Tue Feb 06, 2018 8:21 am Ooooo, I spy a JR135 FM receiver in your stash and a synthesized JR but too bad they're 40mhz, those synthesized jobbies and modules were the ants pants back in the day.
Yeah, I have two or three of those sitting around, in 27 and 40MHz, with transmitters to match. Nice gear, very high tech for my twiddling thumbs :roll: . Have you seen the synthesised Losi version?

RC10th wrote: Tue Feb 06, 2018 8:21 am I found this in my stash of stuff for some reason. It shows the twelve 27mhz AM crystals that Jeff was talking about, there were 6 typically but you could get halves. The 29 is foreign to me, it's like speaking Chinese.
Not sure I'd follow the 29MHz frequency numbers.... they're pretty badly listed on that - 16 / 26 / 36 all being the same is a bit of a giveaway! This list also has one of the weird things I've seen, with the highest 27MHz crystal being marked as 27.245, when I've been using 27.255 as a 'default' frequency for years.

Alex
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Re: 27 MHz vs. 75 MHz

Post by RC10th »

Conspiracy :shock: does that mean there are actually..... 13?

:lol:

Maybe they just wanted to confuse people with the 16/26/36 thing
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