I have slowly been modifying a Heng Long KV-1 tank for long range FPV. It has been an expensive endeavor buying and trying different parts. When it comes to ground based FPV some of what works good in the air does not necessarily work good on the ground. I have tried 1.2GHz and 2.4GHz video transmitters of different milliwatts. What seems to work best for me has been a 900MHz - 500mW video system. It has better reception going around trees and objects. Increasing the milliwatt output of the video transmitter did not yield any better results. I have added 2 infrared LED clusters for night vision. All other LEDs and speaker on tank have been disabled. At night this tank can be heard from the gears but not seen. I have been able to go 670 ft. from base so far. After return trip the battery is exhausted. The weight of this tank in 13.75 lbs. An 8dBi flat patch antenna is on order for hopefully better video quality at longer range. This is still a work in progress. Here are a list of parts that have been added. I hope this thread helps people who are interested in tank based FPV.

a) TK20E receiver board
b) Futaba FUTK4200 4YF 2.4GHz transmitter & R2004GF receiver
c) 900MHz 500mW transmitter with 5dBi omni antenna
d) Oracle Diversity Controller with 2 x 5dBi omni antenna receivers
e) 2 very bright IR LEDs for night vision
f) 7.2v 5000mAh battery
g) Taigen (Asiatam) metal hull with bearings
h) Green laser
i) Modified airsoft gun for use with TK20E board
j) DPCAV Tiny-Mic
k) PZ0420 camera with 4mm low light lens

sweet !!! may look into lipo power say 10,000 mah 7.4v with cut off . will give you more run time and a bit more power . and heck if it can fit try two parallel so the voltage stays the same but double the mah .

Thank you for the information. I did not know they had 10,000 mAh batteries. What do you mean by cut off?

lipo cut off to protect the lipo as you cant run them below 3.2v per cell .
and yes the large cap batteries were intended for large edf jets and boats .

All radio is line of site, 2.4 way bad 27 much better. Lower frequency is better.
Darryl

My first choice after researching radios was 72MHz. The only ones I found for ground use were on eBay and were expensive. I do plan to go that route when I can find a good deal. My use of the 2.4GHz was for the TK20E board because that was recommended by their website and it was cheap. Thanks for the heads up Darryl.

Radio frequencies for FPV
The 27 Mhz Band – Illegal to use for radio controlled aircraft

The 35 Mhz Band

It was the most popular and commonly used band in the FPV sector. This band has very good range properties over 1 mile range with standard equipment. It is being overtaken now with UHF systems becoming available on UK legal bands with none of the 35Mhz pitfalls

The downside of this frequency is the ability for another user to be on the same frequency by mistake and shoot your FPV platform down. This is why at meetings everyone’s channels are logged down and channels are assigned to users so two channels can not be used at the same time.

To identify your channel on known crystal frequencies :

Channel 55 34.950 Channel 67 35.070 Channel 79 35.190
Channel 56 34.960 Channel 68 35.080 Channel 80 35.200
Channel 57 34.970 Channel 69 35.090 Channel 81 35.210
Channel 58 34.980 Channel 70 35.100 Channel 82 35.220
Channel 59 34.990 Channel 71 35.110 Channel 83 35.230
Channel 60 35.000 Channel 72 35.120 Channel 84 35.240
Channel 61 35.010 Channel 73 35.130 Channel 85 35.250
Channel 62 35.020 Channel 74 35.140 Channel 86 35.260
Channel 63 35.030 Channel 75 35.150 Channel 87 35.270
Channel 64 35.040 Channel 76 35.160 Channel 88 35.280
Channel 65 35.050 Channel 77 35.170 Channel 89 35.290
Channel 66 35.060 Channel 78 35.180 Channel 90 35.300

To identify the channel number of an untagged crystal:

If your crystals have the frequency stated but not channel how can you define which channels it on ?

Well that depends on what the crystals marked up with, either 34. something or 35. something.

If its marked 34.___ then you take 40 from the numbers after the decimal place, so for instance if its marked 34.950 then take 40 off the 95. This gives you 55, so its on channel 55. If its marked 34.990 then take 40 off the 99 and you get channel 59.

If the crystals are marked 35.___ then you need to add 60 to the numbers after the decimal. So crystals marked 35.180 would be 18 + 60 = 78, so that would be channel 78. Crystals marked with 35.240 would be 24 + 60 = channel 84

All 35 mhz radio control equipment must carry an approval sticker or an official CE marking. Equipment bearing either of these markings shows that the equipment has been tested and approved for use in the UK.
If your 35 MHz equipment carries neither marking, it may not be suitable or fit the criteria required for safe use in the UK.

The 40 Mhz Band

The 40 Mhz band is for land based RC only, no airborne use allowed

The 72 Mhz Band

72 Mhz is not a legal frequency for the use of any model control in the UK and should never be considered

The 2.4 Ghz Band

2.4Ghz has gained lots in its popularity over the years, its a viable choice of band for FPV control, has decent range and means you can fly amongst other 2.4 users with no problems. The 2.4Ghz systems use FHSS or Frequency Hopping Spectrum Spread technology. What it basically means is that instead of being tethered to the one channel on the band, the transmitters output hops between several channels back and forth. The signal from each transmitter is encoded and has its own signature. This is so many users can hop across the same channels without conflicting with each other. The only thing is as time has past a lot of users have reported brownout problems with some of these systems and rebinding takes to long as the plane falls out the sky. This is normally Spektrum DSM2 systems that were behind the times with technology. Thankfully Spektrum have now released DSMx radio`s that are a lot better now. Futaba`s FASST systems never had this problem.

If you are using an old 35Mhz radio and would like to upgrade it to 2.4Ghz this is easily done. There are now 2.4Ghz upgrade kits available from companies such as FRSKY that manufacture these units that also can incorporate telemetry connection with the plane so you can monitor key values such as battery condition as you fly.

The other problem with 2.4Ghz radio control is you cant use it with 2.4Ghz video gear. It is not because of the ill informed opinions that 2.4 video devices can down 2.4ghz planes, its simply because the 2.4Ghz control signal wrecks the 2.4Ghz video signal as it hops about the band. In which case the use of 5.8Ghz video solves all this in one easy fix. 5.8ghz being a much cleaner band tends to have a lot less interference problems associated with 2.4Ghz video as well.

UHF Band

The 433 Mhz UHF Band is a popular choice abroad. Its used in many FHSS (Frequency Hopping Spread Spectrum) systems for very long range of many km. One manufacturer has recorded full control in excess of 25km away. Claims go up as far as 70km possible.

Again 433 Mhz band even frequency hopping technology is still illegal in the UK.

In the UK 459Mhz is the allocated band for UHF airborne control systems. Until recently there were no such commecial systems available to us, but ImmersionRC have now made firmware available for UK users which enables EZUHF to use the 459Mhz band and with UK legal 100mw output. This system is one of the best available. Many FPV users now use UHF exclusively because of the clear band and the huge range even the UK legal units offer.

There are no UHF radios to buy off the shelf though. To have your system as a UHF system means checking its compatibility with your current radio, then connecting the stand alone UHF unit to it. This is normally just the power wires for the UHF system and a PPM signal for the UHF system to broadcast. So a little research and DIY is required sometimes. Futaba radios though are normally catered for as there trainer socket can be used to simply plug into to meet the above criteria. Some UHF systems are sold with the optional Futaba plug enabling the unit to be plug and play out the box.

If you are a little more hands on, the OpenLRS system from FLYTRON is an open source UHF system that is able to use the 459Mhz band as well. This is a more involved setup, you need to be familiar with Arduino programming, or at least know how to connect and flash the transmitter and receiver to program the units through Arduino 0022 or above. Once flashed though it is a simple case of plug and play. The great feature of this system is that when you program it through the easy to use software you can choose how many channels it hops over, exactly which channels if you so wish and change the signals unique signature to what ever you want. It is still in its infancy with 459Mhz testing being done daily, but results so far exceed predicted hopes.

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make sure you check you local laws regarding radio use and fpv use . as each state and also contry for that matter . hope some of this info helps .

Thanks for that information rcphreak.

Here are my new upgrades so far. By adding a new antenna cable to the 900MHz video transmitter instead of the cable I cut and soldered in the video quality improved a lot at longer range. I added a small fan to help keep down the heat generated by the video transmitter. An 8 dBi patch antenna has also helped on the video quality at longer range. The Taigen metal hull with bearings have added more traveling distance to the battery life by taking away the friction of the plastic wheels on plastic suspension arms that came with the stock bottom hull. The plastic arms were also starting to wear grooves in them with the added weight. As the tank is rather slow I am concentrating on the best video quality I can get as there are trees to somewhat block my line of sight.

A hard pill to swallow. About 500 ft. away somewhere in the dark in a field the screw that holds on one of the back sprockets came off along with half of the sprocket. Not sure how far it traveled before it threw off the track. It is like trying to find a needle in a haystack. No luck so far. Not that it is a big deal but I live in Texas and have to buy another sprocket from Germany. Liquid Thread Lock you are now a friend of mine.

im not trying to bring up bad memories but about how much do you have in this bad ass tank .

About $1,419.00 in parts the tank is currently equipped with and another $998.00 in parts that have been tried out and taken off. I keep my expenses on a spreadsheet because I have bought parts from so many different suppliers if I break or lose something I can repurchase it without to much searching. My friend says that after you spend $1,000.00 on an rc tank it starts being an investment. On a lighter note, after 2 days of searching I found the lost sprocket. It seems the tank can travel about 150 ft. partially up a hill on half a back sprocket before throwing the track. Unfortunately I already ordered 2 new sprockets before I found the lost one. Make that $1,028.00 in unused parts now.

well i never look at it as an investment because of the love for the hobby as unlike investments you will never recover the cost of it more like a huge loss . but thats why itell people dont go and throw huge ammounts of cash thinking its going to be worth more if resold . im the same way i thew 500+ at my micro desert truck and if i were to try and sell it it wouldnt bring over a buck fifty at the most . but it was the love of building and the hobby oh and the devil lol that made me do it

I will try to make a video when I get the chance. Right now I have a few windows opened up trying to figure what to modify next. The devil has one hand on the mouse and the other on my wallet. I will have to wait to see what happens.

lol wating for the vid .just picked up an ignite rc justice dealer air soft . from a good will it works great but range is poor it may have a loose wire ( maby that is why it made it there ) but to my suprise you for sure dont want to be hit in the face the air soft is pretty strong .